Results for "constant"

Filters

Flashcards

Constantine the Great
Updated 5d ago
flashcards Flashcards (10)
biology 2.1Unit 2.1: Mitosis and Meiosis Introduction By the end of this section, you should be able to: Define a chromosome. Define DNA as the genetic material. Define genes. Describe the structure of chromosomes. Describe the components of DNA. Define mitosis and describe its stages. Define meiosis and describe its stages. Relate the events of meiosis to the formation of sex cells. Compare mitosis and meiosis. Chromosomes, Genes, and DNA Almost all the cells of your body—except for mature red blood cells—contain a nucleus, which acts as the control center of the cell. The nucleus holds all the information needed to make a new cell and, ultimately, a new individual. Inside the nucleus are chromosomes, thread-like structures that store genetic information passed from parents to offspring. Chromosomes are made up of DNA (deoxyribonucleic acid), a molecule that carries the instructions needed to make all the proteins in your body. Many of these proteins are enzymes, which control the production of other chemicals and affect everything about how your body functions. Each species has a specific number of chromosomes: Humans have 46 chromosomes (23 pairs). Tomatoes have 24 chromosomes (12 pairs). Elephants have 56 chromosomes (28 pairs). Half of your chromosomes come from your mother, and the other half from your father. These chromosomes are arranged in homologous pairs, meaning they contain matching sets of genes. A karyotype is a special photograph that arranges chromosomes into their pairs. In humans, 22 pairs of chromosomes are called autosomes, which control most body functions. The 23rd pair is the sex chromosomes, which determine whether you are male or female: Females have two X chromosomes (XX). Males have one X and one Y chromosome (XY). DNA Structure DNA is a long, twisted molecule shaped like a double helix (a spiraled ladder). Each strand of DNA is made up of smaller molecules called nucleotides, which consist of: A phosphate group A sugar (deoxyribose) A nitrogen base The four nitrogen bases in DNA are: Adenine (A) → Always pairs with Thymine (T) Cytosine (C) → Always pairs with Guanine (G) Genes are small segments of DNA that carry instructions for making proteins. The sequence of these bases acts like a biological code, directing the cell to create specific proteins. In 1953, James Watson and Francis Crick, using data from Rosalind Franklin’s X-ray photographs, discovered the double-helix structure of DNA. Their discovery led to a huge increase in genetic research, including the Human Genome Project, which mapped all human genes. Mitosis (Cell Division for Growth and Repair) All body cells (somatic cells) divide using mitosis, a type of cell division that creates two identical daughter cells. Mitosis is essential for: Growth (producing new cells). Tissue repair (replacing damaged or old cells). Asexual reproduction (producing offspring with identical DNA). Stages of Mitosis Interphase The cell prepares for division by copying its DNA. Chromosomes are not visible under a microscope. Prophase Chromosomes condense and become visible. The nuclear membrane breaks down. Metaphase Chromosomes line up in the center of the cell. Spindle fibers attach to each chromosome. Anaphase The spindle fibers pull the sister chromatids apart to opposite ends of the cell. Telophase A new nuclear membrane forms around each set of chromosomes. The cell is almost ready to split. Cytokinesis The cytoplasm divides, forming two identical daughter cells. Mitosis is constantly occurring in areas like your skin and bone marrow, where new cells are needed regularly. Meiosis (Cell Division for Reproduction) Unlike mitosis, meiosis occurs only in the reproductive organs (testes in males, ovaries in females) and produces gametes (sperm and egg cells). Gametes have half the number of chromosomes (haploid, n=23) so that when fertilization occurs, the new cell has the correct chromosome number (diploid, 2n=46). Stages of Meiosis Meiosis consists of two rounds of cell division, resulting in four non-identical cells. Meiosis I: Prophase I – Chromosomes pair up and exchange genetic material (crossing over). Metaphase I – Chromosome pairs line up in the center of the cell. Anaphase I – Chromosome pairs separate and move to opposite ends of the cell. Telophase I & Cytokinesis – The cell splits into two haploid daughter cells. Meiosis II (similar to mitosis): 5. Prophase II – Chromosomes condense again. 6. Metaphase II – Chromosomes line up in the center. 7. Anaphase II – Sister chromatids separate and move to opposite sides. 8. Telophase II & Cytokinesis – Four unique haploid gametes are formed. Each gamete is genetically different due to crossing over and random chromosome distribution. Mitosis vs. Meiosis: Key Differences Importance of Mitosis and Meiosis Mitosis ensures that cells grow, repair damage, and replace old cells. Meiosis allows genetic diversity, which is essential for evolution and survival. Summary Chromosomes carry genetic information in the form of DNA. Genes are sections of DNA that code for proteins. Mitosis produces two identical daughter cells for growth and repair. Meiosis creates four non-identical sex cells for reproduction. Mitosis ensures genetic stability, while meiosis introduces genetic diversity
Updated 7d ago
flashcards Flashcards (6)
IPA constants
Updated 7d ago
flashcards Flashcards (56)
Know the relationship between molecular weight and rate of diffusion The rate of diffusion is inversely proportional to the molecular weight Small weight-fast diffusion; heavy weight-slow diffusion Identify RBC’s in various solution and determine tonicity Tonicity - the ability of an extracellular solution to make water move into or out of a cell by osmosis If a cell is placed in a hypertonic solution, there will be a net flow of water out of the cell, and the cell will lose volume (shrink). A solution will be hypertonic to a cell if its solute concentration is higher than that inside the cell, and the solutes cannot cross the membrane. If a cell is placed in a hypotonic solution, there will be a net flow of water into the cell, the cell will gain volume (bigger). If the solute concentration outside the cell is lower than inside the cell, then solutes cannot cross the membrane, then the solution is hypotonic to the cell. If a cell is placed in an isotonic solution, there will be no set flow of water into or out of the cell, and the cell’s volume will remain stable. If the solute concentration outside the cell is the same as inside the cell, and the solutes cannot cross the membrane, the solution is isotonic to the cell. Homeostatic feedback loop for respiratory rate, heart rate and temperature Respiratory Rate: Stimulus : The level of carbon dioxide (CO2) in the blood increases (often due to exercise or hypoventilation) . Receptors: Chemoreceptors in the medulla oblongata, carotid arteries, and aortic arch detect changes in blood pH and CO2 levels Control Center: The medulla oblongata processes this information Effectors: Respiratory muscles (diaphragm and intercostal) adjust breathing rate and depth Response: Increased respiratory rate removes CO2 and increases O2 intake, restoring normal pH and gas levels. Heart Rate: Stimulus : Changes in blood pressure, O2, CO2, or pH levels Receptors: Baroreceptors (detect blood pressure changes) in the carotid sinus and aortic arch; chemoreceptors monitor blood chemistry Control Center: The medulla oblongata (cardiac center) processes signals Effectors : The autonomic nervous system (ANS) adjusts heart rate through the sympathetic nervous system (increases heart rate) or parasympathetic nervous system (decreases heart rate) Response : Heart rate increases during low O2 or low blood pressure (to circulate oxygen) and decreases when homeostasis is restored. Temperature Regulation Stimulus: Changes in body temperature (hyperthermia or hypothermia) Receptors: Thermoreceptors in the skin and hypothalamus detect temperature fluctuations. Control Center: The hypothalamus processes this information and signals effectors Effectors and Responses: If too hot: Blood vessels dilate (vasodilation) to release heat, and sweat glands produce sweat for cooling If too cold: Blood vessels constrict (vasoconstriction) to retain heat, and shivering generates warmth. Steps of a generic homeostatic feedback loop Stimulus : A change in the internal or external environment that disrupts homeostasis (eg. temperature change, pH levels, blood sugar levels) Sensor (Receptor) : Specialized cells or receptors detect the change and send information to the control center. Control Center (Integrator): Often the brain or endocrine glands, this component processes the information from the sensors and determines the appropriate response to restore balance. Effector: This component carries out the response to the stimulus as dictated by the control center. Effectors can be muscles or glands that help to counteract the change. Response: The action taken by the effectors to restore homeostasis. This could involve increasing or decreasing a physiological process (e.g. sweating to cool down or shivering to warm up) Feedback: The results of the response are monitored. If homeostasis is restored, the system maintains its state; if not, the loop may repeat, continuing to adjust until balance is achieved. How to evaluate data to determine the set point, error, and disturbance Identify the set point The set point is the optimal level or range that the system aims to maintain. To determine the set point: Gather baseline data: Collect data over a period to understand the normal range for the variable in question (e.g. body temp., BP, blood glucose levels) Analyze Trends: Look for patterns in the data to identify the average or median value that represents the stable condition of the system. Consult Literature: Reference established physiological norms or previous studies to confirm the typical set point for the variable. Assess Disturbance A disturbance is any factor or event that causes a deviation from the set point. To evaluate disturbances: Identify External and Internal Factors: Analyze the data for any external influences (e.g. environmental changes, dietary habits) or internal changes (e.g. illness, stress) that might have impacted the variable. Quantity Disturbance: Measure the magnitude and duration of the disturbance. This can be done by comparing the data points during the disturbance against the established set point. Monitor Changes: Track how the system responds to disturbances over time to assess their impact on maintaining homeostasis. WBC types and normal distribution values/ abnormal values and what those values indicate (infections/diseases) (Never Let Monkeys Eat Bananas) Neutrophils (50-70%) - First responders to infections, especially bacterial. High levels indicate bacterial infections, inflammation, or stress. Low levels can indicate bone marrow disorders or severe infections. Lymphocytes (20-40%) - Include B cells and T cells, important for immunity. High levels can suggest viral infections or leukemia, while low levels might indicate immune deficiency. Monocytes (2-8%) - Help with cleaning up dead cells and fighting infections. High levels can be linked to chronic infections or autoimmune diseases. Eosinophils (1-4%) - Involved in allergic reactions and fighting parasites. Elevated levels may indicate allergies or parasitic infections. Basophils (0.5-1%) - Release histamine during allergic reactions. High levels might be see in allergic conditions or blood disorders. Normal WBC Count Total WBC Count: 4000-11000 cells per microliter of blood (varies slightly by lab) Leukocytosis (High WBC): Can indicate infection, inflammation, stress, or leukemia Leukopenia (Low WBC): Can result from bone marrow disorders, viral infections, or autoimmune diseases Neutrophils: Banded vs Segmented Neutrophils are the most abundant type of white blood cells and play a crucial role in fighting infections. They exist in different stages of maturation: Banded Neutrophils (“Bands”) - Immature Neutrophils Appearance: Have a curved, unsegmented nucleus (band-shaped) Normal Range: 0-6% of total WBC count (~0-700/uL) Clinical Significance: Increased Bands (Bandemia) -> Indicates an acute bacterial infection or severe stress (e.g. sepsis). The bone marrow releases immature neutrophils in response to infection. Low Bands -> Not clinically significant unless the total WBC count is low, which could suggest bone marrow suppression. Segmented Neutrophils (“Segs”) - Mature Neutrophils Appearance: Have a segmented nucleus with 2-5 lobes Normal Range: 50-70% of total WBC count (~2500-7000/uL) Clinical Significance: High Segs (Neutrophilia) -> Suggests bacterial infections, stress, chronic inflammation, or leukemia Low Segs (Neutropenia) ->Can be caused by viral infections, bone marrow disorders, chemotherapy, or autoimmune diseases. Discuss the stages of cell cycle/mitosis-which stages are longest/shortest The cell cycle is a series of events that cells go through to grow and divide. It consists of two main phases: Interphase (Longest Phase) – Preparation for division Mitosis (Shortest Phase) – Actual cell division Stages of the Cell Cycle Interphase (90% of the Cell Cycle – Longest Phase) Interphase is the period of cell growth and DNA replication. It has three subphases: G1 Phase (Gap 1) The cell grows, produces proteins, and prepares for DNA replication. Longest variable phase; some cells may stay here indefinitely (e.g., neurons in G0 phase). S Phase (Synthesis) DNA replication occurs, ensuring each daughter cell gets a complete genome. Takes about 6-8 hours in human cells. G2 Phase (Gap 2) The cell prepares for mitosis by producing proteins and organelles. Shorter than G1 but still significant in length. Mitosis: Prophase, Metaphase, Anaphase, Telophase Know proportional and inversely proportional relationships Direct (Proportional) Relationship When two quantities increase or decrease together at a constant rate, they are directly proportional. Inversely Proportional When one variable increases, the other decreases proportionally. Know relationship between molecular weight and rate of diffusion The rate of diffusion of a substance is inversely proportional to the square root of its molecular weight. Lighter molecules diffuse faster Heavier molecules diffuse slower due to greater mass. Know relationship between filtration rate and pressure of fluid or weight of fluid Filtration rate is directly proportional to the pressure or weight of the fluid driving the filtration process. Higher pressure → Higher filtration rate Lower pressure → Lower filtration rate Know why men and women blood values are different The differences in blood values between men and women are due to biological, hormonal, and physiological factors
Updated 8d ago
flashcards Flashcards (8)
Chapter 6: Adolescence Growth in Adolescence Puberty is a period of rapid growth and sexual maturation. These changes begin sometime l between eight and fourteen. Girls begin puberty at around ten years of age and boys begin approximately two years later. Pubertal changes take around three to four years to complete. Adolescents experience an overall physical growth spurt. The growth proceeds from the extremities toward the torso. This is referred to as distalproximal development. First the hands grow, then the arms, hand finally the torso. The overall physical growth spurt results in 10-11 inches of added height and 50 to 75 pounds of increased weight. The head begins to grow sometime after the feet have gone through their period of growth. Growth of the head is preceded by growth of the ears, nose, and lips. The difference in these patterns of growth result in adolescents appearing awkward and out-of-proportion. As the torso grows, so do the internal organs. The heart and lungs experience dramatic growth during this period. During childhood, boys and girls are quite similar in height and weight. However, gender differences become apparent during adolescence. From approximately age ten to fourteen, the average girl is taller, but not heavier, than the average boy. After that, the average boy becomes 223 both taller and heavier, although individual differences are certainly noted. As adolescents physically mature, weight differences are more noteworthy than height differences. At eighteen years of age, those that are heaviest weigh almost twice as much as the lightest, but the tallest teens are only about 10% taller than the shortest (Seifert, 2012). Both height and weight can certainly be sensitive issues for some teenagers. Most modern societies, and the teenagers in them, tend to favor relatively short women and tall men, as well as a somewhat thin body build, especially for girls and women. Yet, neither socially preferred height nor thinness is the destiny for many individuals. Being overweight, in particular, has become a common, serious problem in modern society due to the prevalence of diets high in fat and lifestyles low in activity (Tartamella et al., 2004). The educational system has, unfortunately, contributed to the problem as well by gradually restricting the number of physical education courses and classes in the past two decades. Average height and weight are also related somewhat to racial and ethnic background. In general, children of Asian background tend to be slightly shorter than children of European and North American background. The latter in turn tend to be shorter than children from African societies (Eveleth & Tanner, 1990). Body shape differs slightly as well, though the differences are not always visible until after puberty. Asian background youth tend to have arms and legs that are a bit short relative to their torsos, and African background youth tend to have relatively long arms and legs. The differences are only averages, as there are large individual differences as well. Sexual Development Typically, the growth spurt is followed by the development of sexual maturity. Sexual changes are divided into two categories: Primary sexual characteristics and secondary sexual characteristics. Primary sexual characteristics are changes in the reproductive organs. For males, this includes growth of the testes, penis, scrotum, and spermarche or first ejaculation of semen. This occurs between 11 and 15 years of age. For females, primary characteristics include growth of the uterus and menarche or the first menstrual period. The female gametes, which are stored in the ovaries, are present at birth, but are immature. Each ovary contains about 400,000 gametes, but only 500 will become mature eggs (Crooks & Baur, 2007). Beginning at puberty, one ovum ripens and is released about every 28 days during the menstrual cycle. Stress and higher percentage of body fat can bring menstruation at younger ages. Male Anatomy: Males have both internal and external genitalia that are responsible for procreation and sexual intercourse. Males produce their sperm on a cycle, and unlike the female's ovulation cycle, the male sperm production cycle is constantly producing millions of sperm daily. The main male sex organs are the penis and the testicles, the latter of which produce semen and sperm. The semen and sperm, as a result of sexual intercourse, can fertilize an ovum in the female's body; the fertilized ovum (zygote) develops into a fetus which is later born as a child. Female Anatomy: Female external genitalia is collectively known as the vulva, which includes the mons veneris, labia majora, labia minora, clitoris, vaginal opening, and urethral opening. Female internal reproductive organs consist of the vagina, uterus, fallopian tubes, and ovaries. The uterus hosts the developing fetus, produces vaginal and uterine secretions, and passes the male's sperm through to the fallopian tubes while the ovaries release the eggs. A female is born with all her eggs already produced. The vagina is attached to the uterus through the cervix, while the uterus is attached to the ovaries via the fallopian tubes. Females have a monthly reproductive cycle; at certain intervals the ovaries release an egg, which passes through the fallopian tube into the uterus. If, in this transit, it meets with sperm, the sperm might penetrate and merge with the egg, fertilizing it. If not fertilized, the egg is flushed out of the system through menstruation. Secondary sexual characteristics are visible physical changes not directly linked to reproduction but signal sexual maturity. For males this includes broader shoulders and a lower voice as the larynx grows. Hair becomes coarser and darker, and hair growth occurs in the pubic area, under the arms and on the face. For females, breast development occurs around age 10, although full development takes several years. Hips broaden, and pubic and underarm hair develops and also becomes darker and coarser. Acne: An unpleasant consequence of the hormonal changes in puberty is acne, defined as pimples on the skin due to overactive sebaceous (oil-producing) glands (Dolgin, 2011). These glands develop at a greater speed than the skin ducts that discharges the oil. Consequently, the ducts can become blocked with dead skin and acne will develop. According to the University of California at Los Angeles Medical Center (2000), approximately 85% of adolescents develop acne, and boys develop acne more than girls because of greater levels of testosterone in their systems (Dolgin, 2011). Experiencing acne can lead the adolescent to withdraw socially, especially if they are self-conscious about their skin or teased (Goodman, 2006). Effects of Pubertal Age: The age of puberty is getting younger for children throughout the world. According to Euling et al. (2008) data are sufficient to suggest a trend toward an earlier breast development onset and menarche in girls. A century ago the average age of a girl’s first period in the United States and Europe was 16, while today it is around 13. Because there is no clear marker of puberty for boys, it is harder to determine if boys are maturing earlier too. In addition to better nutrition, less positive reasons associated with early puberty for girls include increased stress, obesity, and endocrine disrupting chemicals. Cultural differences are noted with Asian-American girls, on average, developing last, while African American girls enter puberty the earliest. Hispanic girls start puberty the second earliest, while European-American girls rank third in their age of starting puberty. Although African American girls are typically the first to develop, they are less likely to experience negative consequences of early puberty when compared to European-American girls (Weir, 2016). Research has demonstrated mental health problems linked to children who begin puberty earlier than their peers. For girls, early puberty is associated with depression, substance use, eating disorders, disruptive behavior disorders, and early sexual behavior (Graber, 2013). Early maturing girls demonstrate more anxiety and less confidence in their relationships with family and friends, and they compare themselves more negatively to their peers (Weir, 2016). Problems with early puberty seem to be due to the mismatch between the child’s appearance and the way she acts and thinks. Adults especially may assume the child is more capable than she actually is, and parents might grant more freedom than the child’s age would indicate. For girls, the emphasis on physical attractiveness and sexuality is emphasized at puberty and they may lack effective coping strategies to deal with the attention they may receive. 226 Figure 6.4 Source Additionally, mental health problems are more likely to occur when the child is among the first in his or her peer group to develop. Because the preadolescent time is one of not wanting to appear different, early developing children stand out among their peer group and gravitate toward those who are older. For girls, this results in them interacting with older peers who engage in risky behaviors such as substance use and early sexual behavior (Weir, 2016). Boys also see changes in their emotional functioning at puberty. According to Mendle, Harden, Brooks-Gunn, and Graber (2010), while most boys experienced a decrease in depressive symptoms during puberty, boys who began puberty earlier and exhibited a rapid tempo, or a fast rate of change, actually increased in depressive symptoms. The effects of pubertal tempo were stronger than those of pubertal timing, suggesting that rapid pubertal change in boys may be a more important risk factor than the timing of development. In a further study to better analyze the reasons for this change, Mendle et al. (2012) found that both early maturing boys and rapidly maturing boys displayed decrements in the quality of their peer relationships as they moved into early adolescence, whereas boys with more typical timing and tempo development actually experienced improvements in peer relationships. The researchers concluded that the transition in peer relationships may be especially challenging for boys whose pubertal maturation differs significantly from those of others their age. Consequences for boys attaining early puberty were increased odds of cigarette, alcohol, or another drug use (Dudovitz, et al., 2015). Gender Role Intensification: At about the same time that puberty accentuates gender, role differences also accentuate for at least some teenagers. Some girls who excelled at math or science in elementary school, may curb their enthusiasm and displays of success at these subjects for fear of limiting their popularity or attractiveness as girls (Taylor et al/, 1995; Sadker, 2004). Some boys who were not especially interested in sports previously may begin dedicating themselves to athletics to affirm their masculinity in the eyes of others. Some boys and girls who once worked together successfully on class projects may no longer feel comfortable doing so, or alternatively may now seek to be working partners, but for social rather than academic reasons. Such changes do not affect all youngsters equally, nor affect any one youngster equally on all occasions. An individual may act like a young adult on one day, but more like a child the next. Adolescent Brain The brain undergoes dramatic changes during adolescence. Although it does not get larger, it matures by becoming more interconnected and specialized (Giedd, 2015). The myelination and 227 development of connections between neurons continues. This results in an increase in the white matter of the brain and allows the adolescent to make significant improvements in their thinking and processing skills. Different brain areas become myelinated at different times. For example, the brain’s language areas undergo myelination during the first 13 years. Completed insulation of the axons consolidates these language skills but makes it more difficult to learn a second language. With greater myelination, however, comes diminished plasticity as a myelin coating inhibits the growth of new connections (Dobbs, 2012). Even as the connections between neurons are strengthened, synaptic pruning occurs more than during childhood as the brain adapts to changes in the environment. This synaptic pruning causes the gray matter of the brain, or the cortex, to become thinner but more efficient (Dobbs, 2012). The corpus callosum, which connects the two hemispheres, continues to thicken allowing for stronger connections between brain areas. Additionally, the hippocampus becomes more strongly connected to the frontal lobes, allowing for greater integration of memory and experiences into our decision making. The limbic system, which regulates emotion and reward, is linked to the hormonal changes that occur at puberty. The limbic system is also related to novelty seeking and a shift toward interacting with peers. In contrast, the prefrontal cortex which is involved in the control of impulses, organization, planning, and making good decisions, does not fully develop until the mid-20s. According to Giedd (2015) the significant aspect of the later developing prefrontal cortex and early development of the limbic system is the “mismatch” in timing between the two. The approximately ten years that separates the development of these two brain areas can result in risky behavior, poor decision making, and weak emotional control for the adolescent. When puberty begins earlier, this mismatch extends even further. Teens often take more risks than adults and according to research it is because they weigh risks and rewards differently than adults do (Dobbs, 2012). For adolescents the brain’s sensitivity to the neurotransmitter dopamine peaks, and dopamine is involved in reward circuits, so the possible rewards outweighs the risks. Adolescents respond especially strongly to social rewards during activities, and they prefer the company of others their same age. Chein et al. (2011) found that peers sensitize brain regions associated with potential rewards. For example, adolescent drivers make risky driving decisions when with friends to impress them, and teens are much more likely to commit crimes together in comparison to adults (30 and older) who commit them alone (Steinberg et al., 2017). In addition to dopamine, the adolescent brain is affected by oxytocin which facilitates bonding and makes social connections more rewarding. With both dopamine and oxytocin engaged, it is no wonder that adolescents seek peers and excitement in their lives that could end up actually harming them. 228 Because of all the changes that occur in the adolescent brain, the chances for abnormal development can occur, including mental illness. In fact, 50% of the mental illness occurs by the age 14 and 75% occurs by age 24 (Giedd, 2015). Additionally, during this period of development the adolescent brain is especially vulnerable to damage from drug exposure. For example, repeated exposure to marijuana can affect cellular activity in the endocannabinoid system. Consequently, adolescents are more sensitive to the effects of repeated marijuana exposure (Weir, 2015). However, researchers have also focused on the highly adaptive qualities of the adolescent brain which allow the adolescent to move away from the family towards the outside world (Dobbs, 2012; Giedd, 2015). Novelty seeking and risk taking can generate positive outcomes including meeting new people and seeking out new situations. Separating from the family and moving into new relationships and different experiences are actually quite adaptive for society. Adolescent Sleep According to the National Sleep Foundation (NSF) (2016), adolescents need about 8 to 10 hours of sleep each night to function best. The most recent Sleep in America poll in 2006 indicated that adolescents between sixth and twelfth grade were not getting the recommended amount of sleep. On average adolescents only received 7 ½ hours of sleep per night on school nights with younger adolescents getting more than older ones (8.4 hours for sixth graders and only 6.9 hours for those in twelfth grade). For the older adolescents, only about one in ten (9%) get an optimal amount of sleep, and they are more likely to experience negative consequences the following day. These include feeling too tired or sleepy, being cranky or irritable, falling asleep in school, having a depressed mood, and drinking caffeinated beverages (NSF, 2016). Additionally, they are at risk for substance abuse, car crashes, poor academic performance, obesity, and a weakened immune system (Weintraub, 2016). Troxel et al. (2019) found that insufficient sleep in adolescents is a predictor of risky sexual behaviors. Reasons given for this include that those adolescents who stay out late, typically without parental supervision, are more likely to engage in a variety of risky behaviors, including risky sex, such as not using birth control or using substances before/during sex. An alternative explanation for risky sexual behavior is that the lack of sleep negatively affects impulsivity and decision-making processes. Figure 6.7 Source Why do adolescents not get adequate sleep? In addition to known environmental and social factors, including work, homework, media, technology, and socializing, the adolescent brain is also a factor. As adolescent go through puberty, their circadian rhythms change and push back their sleep time until later in the evening (Weintraub, 2016). This biological change not only keeps adolescents awake at night, it makes it difficult for them to wake up. When they are awake too early, their brains do not function optimally. Impairments are noted in attention, academic achievement, and behavior while increases in tardiness and absenteeism are also seen. 229 To support adolescents’ later sleeping schedule, the Centers for Disease Control and Prevention recommended that school not begin any earlier than 8:30 a.m. Unfortunately, over 80% of American schools begin their day earlier than 8:30 a.m. with an average start time of 8:03 a.m. (Weintraub, 2016). Psychologists and other professionals have been advocating for later school times, and they have produced research demonstrating better student outcomes for later start times. More middle and high schools have changed their start times to better reflect the sleep research. However, the logistics of changing start times and bus schedules are proving too difficult for some schools leaving many adolescent vulnerable to the negative consequences of sleep deprivation. Troxel et al. (2019) cautions that adolescents should find a middle ground between sleeping too little during the school week and too much during the weekends. Keeping consistent sleep schedules of too little sleep will result in sleep deprivation but oversleeping on weekends can affect the natural biological sleep cycle making it harder to sleep on weekdays. Adolescent Sexual Activity By about age ten or eleven, most children experience increased sexual attraction to others that affects social life, both in school and out (McClintock & Herdt, 1996). By the end of high school, more than half of boys and girls report having experienced sexual intercourse at least once, though it is hard to be certain of the proportion because of the sensitivity and privacy of the information. (Center for Disease Control, 2004; Rosenbaum, 2006). Adolescent Pregnancy: As can be seen in Figure 6.8, in 2018 females aged 15–19 years experienced a birth rate (live births) of 17.4 per 1,000 women. The birth rate for teenagers has declined by 58% since 2007 and 72% since 1991, the most recent peak (Hamilton, Joyce, Martin, & Osterman, 2019). It appears that adolescents seem to be less sexually active than in previous years, and those who are sexually active seem to be using birth control (CDC, 2016). Figure 6.8 Source Risk Factors for Adolescent Pregnancy: Miller et al. (2001) found that parent/child closeness, parental supervision, and parents' values against teen intercourse (or unprotected intercourse) decreased the risk of adolescent pregnancy. In contrast, residing in disorganized/dangerous neighborhoods, living in a lower SES family, living with a single parent, having older sexually 230 active siblings or pregnant/parenting teenage sisters, early puberty, and being a victim of sexual abuse place adolescents at an increased risk of adolescent pregnancy. Consequences of Adolescent Pregnancy: After the child is born life can be difficult for a teenage mother. Only 40% of teenagers who have children before age 18 graduate from high school. Without a high school degree her job prospects are limited, and economic independence is difficult. Teen mothers are more likely to live in poverty, and more than 75% of all unmarried teen mother receive public assistance within 5 years of the birth of their first child. Approximately, 64% of children born to an unmarried teenage high-school dropout live in poverty. Further, a child born to a teenage mother is 50% more likely to repeat a grade in school and is more likely to perform poorly on standardized tests and drop out before finishing high school (March of Dimes, 2012). Research analyzing the age that men father their first child and how far they complete their education have been summarized by the Pew Research Center (2015) and reflect the research for females. Among dads ages 22 to 44, 70% of those with less than a high school diploma say they fathered their first child before the age of 25. In comparison, less than half (45%) of fathers with some college experience became dads by that age. Additionally, becoming a young father occurs much less for those with a bachelor’s degree or higher as just 14% had their first child prior to age 25. Like men, women with more education are likely to be older when they become mothers. Eating Disorders Figure 6.9 According to the DSM-5-TR (American Psychiatric Association, 2022), eating disorders are characterized by a persistent disturbance of eating or eating-related behavior that results in the altered consumption or absorption of food and that significantly impairs physical health or psychosocial functioning. Although eating disorders can occur in children and adults, they frequently appear during the teen years or young adulthood (National Institute of Mental Health (NIMH), 2016). Eating disorders affect both genders, although rates among women are 2½ times greater than among men. Similar to women who have eating disorders, men also have a distorted sense of body image, including muscle dysmorphia, which is an extreme desire to increase one’s muscularity (Bosson et al., 2019). The prevalence of eating disorders in the United States is similar among Non-Hispanic Whites, Hispanics, African-Americans, and Asians, with the exception that anorexia nervosa is more common among Non-Hispanic Whites (Hudson et al., 2007; Wade et al., 2011). Source Risk Factors for Eating Disorders: Because of the high mortality rate, researchers are looking into the etiology of the disorder and associated risk factors. Researchers are finding that eating disorders are caused by a complex interaction of genetic, biological, behavioral, psychological, and social factors (NIMH, 2016). Eating disorders appear to run in families, and researchers are working to identify DNA variations that are linked to the increased risk of developing eating 231 disorders. Researchers from King’s College London (2019) found that the genetic basis of anorexia overlaps with both metabolic and body measurement traits. The genetic factors also influence physical activity, which may explain the high activity level of those with anorexia. Further, the genetic basis of anorexia overlaps with other psychiatric disorders. Researchers have also found differences in patterns of brain activity in women with eating disorders in comparison with healthy women. The main criteria for the most common eating disorders: Anorexia nervosa, bulimia nervosa, and binge-eating disorder are described in the DSM-5-TR (American Psychiatric Association, 2022) and listed in Table 6.1. Table 6.1 DSM-5-TR Eating Disorders Anorexia Nervosa  Restriction of energy intake leading to a significantly low body weight  Intense fear of gaining weight  Disturbance in one’s self-evaluation regarding body weight Bulimia Nervosa Binge-Eating Disorder  Recurrent episodes of binge eating  Recurrent inappropriate compensatory behaviors to prevent weight gain, including purging, laxatives, fasting or excessive exercise  Self-evaluation is unduly affected by body shape and weight  Recurrent episodes of binge eating  Marked distress regarding binge eating  The binge eating is not associated with the recurrent use of inappropriate compensatory behavior Health Consequences of Eating Disorders: For those suffering from anorexia, health consequences include an abnormally slow heart rate and low blood pressure, which increases the risk for heart failure. Additionally, there is a reduction in bone density (osteoporosis), muscle loss and weakness, severe dehydration, fainting, fatigue, and overall weakness. Anorexia nervosa has the highest mortality rate of any psychiatric disorder (Arcelus et al., 2011). Individuals with this disorder may die from complications associated with starvation, while others die of suicide. In women, suicide is much more common in those with anorexia than with most other mental disorders. The binge and purging cycle of bulimia can affect the digestives system and lead to electrolyte and chemical imbalances that can affect the heart and other major organs. Frequent vomiting can cause inflammation and possible rupture of the esophagus, as well as tooth decay and staining from stomach acids. Lastly, binge eating disorder results in similar health risks to obesity, including high blood pressure, high cholesterol levels, heart disease, Type II diabetes, and gall bladder disease (National Eating Disorders Association, 2016). 232 Figure 6.10 Source Eating Disorders Treatment: To treat eating disorders, adequate nutrition and stopping inappropriate behaviors, such as purging, are the foundations of treatment. Treatment plans are tailored to individual needs and include medical care, nutritional counseling, medications (such as antidepressants), and individual, group, and/or family psychotherapy (NIMH, 2016). For example, the Maudsley Approach has parents of adolescents with anorexia nervosa be actively involved in their child’s treatment, such as assuming responsibility for feeding the child. To eliminate binge eating and purging behaviors, cognitive behavioral therapy (CBT) assists sufferers by identifying distorted thinking patterns and changing inaccurate beliefs
Updated 9d ago
flashcards Flashcards (4)
Constantinople
Updated 11d ago
flashcards Flashcards (9)
Sports & Exercise Science Lectures History of Sport and Exercise Science, highlighting relevance of training principles today. • Historian part of speaker finds interest in history of Sport and Exercise Science. Sport and exercise science history and its evolution. • Sport Science: Systematic approach to understanding factors relating to sports performance. • Exercise Science: Systematic approach to understanding how the human body responds to physical activity. • Agriculture led to sedentary lifestyle and exercise became a way to combat it (0:03:14) • Ancient Chinese philosophers like Confucius and Hippocrates advocated for exercise as a means of maintaining health (5000 years ago) Exercise science history, including Leonardo da Vinci's anatomical sketches and early physiology experiments. • Leonardo da Vinci (1500s) made accurate anatomical sketches, discovering heart as muscle pump and nervous system hierarchy. • William Harvey (1600s) discovered blood circulation in one direction, and Boyle (1600s) found Boyle's law, which explains breathing mechanism. • Johan Bernoulli (1700s) developed mathematical models to explain muscle mechanics, using tractors to investigate muscle contractions. • James Lin discovered the origins of scourgia by inviting vitamin C-rich food, with great success. • Anton Laviesia named oxygen and recognized hydrogen as an element, and his experiments on human respiration led to a better understanding of metabolism and nutrition. Note Sport and Exercise Science sub-disciplines and their roles in sport and clinical contexts. • Sport and Exercise Science sub disciplines explore roles in sporting and clinical contexts (psychologists, biomechanics, nutritionists, strength coaches, physiologists, performance analysts) • Accredited Exercise Physiologists provide individualized exercise programs for high-risk populations (hypertension, heart disease, diabetes, musculoskeletal conditions, injuries) Exercise physiology and biomechanics in sports. • Exercise physiologist specializes in prescribing exercise for patients with chronic diseases or injuries. • Sports physiologist studies the physiological demands of sports and advises athletes on training and competition. • Biochemist analyzes technique and injury mechanisms in sports, measuring mechanical loads and risk assessments. Improving athletic performance through strength training and conditioning. • Unknown Speaker discusses biomechanics and jumping throws, using a three-mesh Castle system to measure angles, velocities, and selections of throwing motion. • Strength and conditioning coach works with athletes to improve strength, power, speed, fitness, acceleration, agility, endurance, and flexibility. • Coach designs programs to reduce injury risk, optimize recovery, and deliver rehab programs in conjunction with medical staff for injured athletes. Motor control, learning, and performance in sports. • Motor control specialists focus on learning, performing, and retaining motor skills over time. • Sport psychologists help athletes overcome barriers to optimal performance, using techniques like visualization and mindfulness. Sports dietitians' role in optimizing athletes' health, performance, and nutrition. • Sports dietitians tailor nutritional strategies for athletes to optimize health, performance, and body composition. • Dietitians recommend food first approach and supplements when necessary, and provide individualized advice and hydration stations. • Unknown Speaker discusses six specialist supplements in Sport and Exercise Science, including nutrition (12:30) • Speaker shares insights on interdisciplinary approach to high performance in surfing, with focus on strength conditioning and sport science (14:45) Functional Anatomy an understanding of how to use a correct terms to describe movement interaction, understand major bones, muscles, joints, and how they work together in human movement, and begin to develop the ability to form a movement. Analysis of exercise and supporting tasks. Despite in this lecture, if you're unfamiliar with anatomy, it might require a second viewing. Beautiful lecture is the ability to stop review. If you require any further help with the content, please reach out to your tutor. So the first thing I understand in anthropical language is that whenever we refer to position or something, we're referring to it in its position when in the anatomical position. So this is the standardized position of the body where it is always direct and facing forwards, with the palms of the side of the body, toes and palms of the hands facing forwards. Having a standard anatomical position is crucial to reference and describe the relationship of body sequence to one another when it is anatomical position. There are three COVID plans from which we can view or segment the body that is essential, frontal and reverse plastics. So the station plane, or the median plane, is the side on view of the body, meaning you see a profile of the person. The frontal plane is also called the corona plane, and there's the view we get between directly at the front or back of the body. And finally, the transverse plane, also called the horizontal plane, is the birds of view of the body. There generally can be from the ground up as well, right, if it's never nearly achieved. And the other understand that the body can be viewed in three different planes. It's relatively straightforward to understand that rotational movement also occurs in each of these three axes. So this is called an axis of rotation, and is essentially an imaginary line about which any rotational movement occurs perpendicular to that Cardinal plane of action, just like the anatomical position and Cardinal planes allow us to describe the relative positions with different body parts. So it doesn't understand axis of rotation allows us to constantly describe human movement. However, most movements of human body typically occur about two or more axes of rotation, which makes the analysis of human movement far more challenging. So you think about the 3x Y and Z plane take elbow flexion like a bicycle. When view from front and the front plane, it looks like the forearm hand is simply moving up towards the face, open, viewed side on from the sagittal plane, you see that the forearm hand also moving away from the body and then back towards the body as it goes through that arc. Movement. This way to understand all three other anatomical positions, the counter planes and the axes of rotation, to be able to accurately describe pure movement. So now we can consider best view in his plans. So in the anatomical position, the most common actually the rotation between the SAP flexion and extension. And we'll go through that few slides for now. Include flexion and extension at the wrist, elbow, shoulder, neck, trunk, hip, knee and ankle. At the ankle. It's also referred to as dorsi flexion and plantar flexion, rather than flexion extension. Multi joint actions can involve both. So kicking your foot forwards involve flexing the hip, swinging forward and extending in the knee. Some of that actually rotation. Best views in the frontal plane include adduction and abduction at the shoulder and hip, lateral flexion at the neck and trunk, as well as radial and ulna deviation at the wrist and diversion and inversion at the ankle. And this is why I move the mechanism, which can result in raw ego the arm actually in breast stroke. Swing is adduction, kicking a stop or the ring forward involved adduction of the hip. Two legs coming together are being added so that's adduction. When the arm is being taken away from the body, it is being abducted. It's been taken away. Finding the transverse plane. Some of the best view axes of rotation and movements include internal and external rotation of the shoulder and hip, and horizontal adduction and abduction for the shoulder and the forearms, pronation and supination and neck and trunk rotation. Each of these three slides are diagrams. Highlight the movements just went through. The next slide go through the names of these moves and what the actions are. Flexion and extension refer to increasing and decreasing the angle in the frontal plane. So for instance, elbow flexion is raising your forearm and hand, while extension is lowering back down. This is truthfully all flexion extension, except for the ankle, which you remember dorsiflexion and plantar flexion. So dorsiflexion refers to moving the top of the foot towards the leg, and plant deflection is away from the leg towards the ground. I find this easier to remember using your plan to flexion as the movement required to step on a plane with your toes. Adduction. And adduction refer to moving away or towards the central plane. Next is protraction and retraction. This is moving something forward or patterns. And a good example is the second level of shoulder blades. When you pull your shoulder blades back and away. This is attraction. Protraction is the opposite elevation and depression. Can be also thought of with regarding the shoulder is raising, like in a shrug, while depression is lowering back down another shoulder blade sample is upward and downward rotation, with upward rotation referring to the rotational movement around access to a point superior and downward rotation, maybe opposite. Medium and lateral rotation referred to rotating toward or away from midnight. So the arms hanging medial rotation is internal rotation of your arm, the shoulder towards midnight, and external or lateral rotation being back away from midnight. Pronation suppression has special terms for forearm movement. With a forearm rotation to have your palm facing upward in an anatomical position in front of supreme and the back of your hands facing forward into pronation. We can also use these terms of the foot, but they are known as inversion, meaning the sole of the foot faces towards mid level E version, when the solar foot rolls away from the middle. Our last two terms, especially with the circumduction, referring to the combination of flexion and attention abduction and medial lateral rotations, and often we could curtain rally, but when we move up arms or legs, it's usually not in a single plane through a multiple plane with multiple positive move and social conduction despises. Now opposition is the movement of bringing tips of your fingers and thumb together. And the reason we also have possible thumbs are very useful with lasers pick up items. Here is a diagram illustrating protraction, retraction, elevation and depression, these lines of upper rotation and downward rotation. So on this slide is a consolidated view of some special actions that only currently in places. So we've got scapular to demonstrate protraction, retraction, depression, elevation, plus upward and downward rotation. You can see that you can invert or divert the ankle. In running terms, we can talk about pronation as collapsing inwards during foot strike, which means I saw the foot faces away from midline. Next is illustrate example of plantar flexion and dorsiflexion and ankle, and define this example of protraction, retraction, elation and depression of the Mandal which is the lower jaw bone. So you would think that with each member of the move toward or away from the midline, or up versus down, all these things, or have anatomical terms to solve the time in terms of the direction of body. So anterior and posterior refer to the front and back of the body in atomic position. You also call them ventral end dorsal, and think of dorsalism, but the dorsal is the dorsal fin on the back, mostly we refer to as anterior and posterior. Superior and inferior refer to the directions towards the head or towards the feet, while medial and lateral refer to the direction towards the midline or away from midline in a sideways direction, approximately distal, our special tendencies to refer to the relative positioning of something compared to another landmark. So if something is distal, it refers to sides located away from a specific area, most often the center of body, and for instance, the hand is visible to the elbow. Proximal refers to sites located towards a specific area, so the COVID The elbow is proximal to the hand. The term distal, or is maximum or distance or proximal indicates proximity. Now last terms are superficial and deep, which require you to think in three days. So something that's superficial is close to the surface or the skin of the body, or something that's deep is away from so muscles are deep to the skin, but superficial to bone. So many of these will become important when we talk about anatomy, as certain structures can be proximal or anterior or superficial to other structures. The human anatomy is built around the scaffolding of the split system. So this slide shows you in the structure an anatom. We're not going to go through that in this lecture for this electron. Functional anatomy is more important than understand the function of the skeleton that bones make up, beyond just being the strong structure holding us together, the way the bones fit together and serve as attachment points for the ligaments, tendons and muscles, serves to allow various movements of the body that we've already discussed. The skeleton by the rib cage also protects wild organs, while the internal structure of the bone allows for the storage of minerals and production of new blood cells. We wouldn't have any of the functional movements we've discussed so far without having a skeleton to support these movements. There are 206, bones in the human body. We don't need to learn them all, but we're certainly discussing some of them in this unit. So basic understanding of the major structure of the skeleton is important, and you can use this as a reference for some of those major bones. In this particular image, the green bones represent the actual skeleton, and the non green turn the perpendicular skeleton thanks to better understand how movement can occur in the body. Is cartilage, which is a stiff but flexible connective tissue found in many applications throughout the body. So cartilage is composed of specialized cells called corona sites. They produce a large amount of extracellular matrix. So cartilage can be classified as three types. We have hyaline cartilage, which forms a smooth surface on articular joint surfaces, with Fibro cartilage that is a part of form of cartilage found at sites such as the pubic symphysis. And you've got elastin cartilage, which can be found in here. Cartilage doesn't actually contain blood vessels instead, the chondrocytes are supplied by diffusion, which is helped by the pumping action generated by the compression of articulate cartilage or flexion of the elastic charge. So because it doesn't have a blood supply, cartilage grows and repairs more slowly, which is why cartilage injuries are so slow to healing athletes and and often require arthroscopic surgery, which are inelastic but flexible bands of connective tissue that attached, attached two bones together so they enhance joint stability by maintaining the alignment of bones and limiting range of motion. Those are the two primary functions keep bone and enhancement stability. The most common injuries involve involving into sprains, which means over stretching and tearing of the fibers, and they can be quite slow to heal. So if we bring that together, we get a joints so these facilitate the movers that we discussed at the front of this lecture, per muscular structure, joined by the ones, separate by cartilage. The form joints, which used to be also called articulations. There are three types of classifications of joint. So we have fibrous joints, which are bound by dense connective tissue. And these are joints in the scale, and they really don't move much. You have a catalyst joint, which, as the name suggests, is a joint with fibrous cartilage separating two bones, such as the symphysis, pubis and the ribs. And again, they don't move very much. And then finally, we have synovial joints, which are bound by a joint capsule in containing ligaments and muscles to allow them to occur. And these are the ones with most interesting in this lecture. So not only a synovial joints most interesting for me, but also the most common type of joint. So the articulate capsule, which surrounds synovial joint forms a kind of SAC around the joint. And so there's also synovial membrane inside the articulate capsule, which secretes synovial fluid, and this lubricates the articular cartilage of the joint services, similar to enjoy car lubricating the moving parts. It also nourishes the joint structure, and it can act as a shock absorber, distributing the stress evenly across the articular surface. So all of this combines to allow for smooth fluid movement joints, and usually without needing an oil change during your lifetime, as we've already gone over, the bones with the joints are held together by ligaments. But what we haven't talked about here is the joints can also contain something else called a bursa, which we'll discuss a bit later. So even though synovial joints are major type of joint, they can also be classified with various types of synovial joints. So we have plain joints, which can be found in the joints between the vertebral articulating surfaces. We've got hinge joints such as the elbow or the knee. We have pivot joints such as the ulnar and radius. We have COVID joints in the fingers. We have several joints, which is the thumbnail and sub joint, such as the hip and joint. Okay, so this is a very useful slide for a reference for various locations where these joints can be found. As I mentioned before, we have bursa which can sometimes occur with some synovial joints. These are small sacks of fibrous tissue filled with synovial fluid, and they are found where different parts move over one another in the body, and they help reduce friction within the joint. So these mostly occur with bones, ligaments, muscles, skin or tendons, over later, and will rub together. If a person comes in flames, it can lead to an injury you might have heard for bursitis, where the bursar releases too much fluid and the joint gets very swollen, and they can make movement difficult. So burst sit around tendons, and so that's the next structure that we look at. So tendons are tough but flexible bands of tissue that attach muscle to bone and help facilitate movement. So like many fibrous structures we've already discussed, they have a limited blood supply, which makes healing and repair slow. Some common tenderness injuries, which are strains or over stretching. Can be a tenderpathy or tenderloin, which is a result of inflammation, and tenderlois, which is a chronic inflammatory condition. Lastly, we have the muscles, and as with the bones, you'll do need to understand some of the basic muscles of the body, but for the for this functional anatomy component, we'll just talk about the functions of the skeleton worker. So essentially, our muscles control our posture. They provide support for the soft tissues in the body. They allow the body to store energy to use during movement exercise. They can guard entrances and agents in the body, and they also produce heat to allow us to regulate our body temperature. When muscle is contracted, it pulls on the tendon of the muscle, which in turn is connected to the bones, bone, and then we get the movement. So the way in which that occurs in a single muscle cell fiber is made up of many myofibrils, which can make up any starters. So within the start of me there's actin and myosin filaments, and that's called an actin mycin cross bridge. And they slide past and pull each other closer together or further to control the movement. So whilst we're over the 700 muscles in the body, here's a list of some of the major muscles that we'll refer to, and you'll cover it in a different unit, but certainly will be exposed as many of these throughout the labs. So reaching the end of this lecture, we now have to use the knowledge from this lecture to answer some applied problems. So during stationary cycling, what plane or planes of movement is this exercise occurring? So what axis of rotation is movement occurring? So we will need to look at a sporting movement or an exercise and describe it in its proper anatomical terms, so not always as simple as stationary cycling. So take this diagonal Wood Chop exercise as an example. This is still quite a basic movement. If there are multiple axes of rotation occurring through multiple planes involving many joints, bones and muscles. And even in a more complex example, we can go to Goldsmith and see movement across multiple axes of rotation of all three planes. For example, the frontal plane, we can see abduction and abduction, as well as inversion and inversion. In the Sagitta plane, we can see flexion and extension in the medial lateral axis. On the transverse plane, we can see rotation around the longitudinal latches. Many real world supporting movements will be like this, involving a complex coordination of many movements across many planes. We will work through all of these in the labs. So to be able to describe all of these different actions using proper environmental terminology, I highly recommend you start the voting time to study with most of your three credit point units. You'll find that towns a week is allocated for full time state, only four hours of that is lectures and labs, which leaves the rest of your time for state. So please use that time, why is it, this particular left of today on functionality, you may have many questions about plans of movement anatomical terms. I'm trying to write them down, bring them to the lab so that we can speak to your tuners about their experiences with learning this material. Thanks for watching this lecture. Body compostion In this lecture, we will cover body composition, the different types of tissue in the human body, and how these are distributed, measured and the impact on our health. of this lecture, you'll have an understanding of the components of body composition and implications of body composition on health. So body composition is the general term that refers to the relative amounts of tissue types of the body, generally related to fat and fat free mass. It is expressed as a percentage of body fat. There are general classifications of body composition, from underweight to severely obese. Body Composition is related to general health and can also have an impact on supporting performance. The assessment of body composition can be used to monitor lifestyle interventions. There are optimal ranges for health and exercise. Professionals administer different Exercise and Nutritional strategies to influence body composition. There any correlations between risk of chronic disease and body position, including coronary heart disease, diabetes, hypertension, some cancers, hyperlipidemia is more commonly referred to as high cholesterol, but encompasses several blood lipids. Body Mass Index is one measure of obesity as a relationship between height and weight. On this low we can see the relative risk of type two diabetes starts increasing rapidly between BMI 25 to 30, which is Catia crisis, overweight, and beyond, which is obese. We can see on the right side that the same relationship holds true for many forms of cancer. Delicately, this pilot, diabetes and cancer can be thought of as lifestyle diseases, and that body composition is one factor which is correlated with the risk of these diseases. Here we can see the five different lenses through which to view body composition. So at the time level, we mostly hydrogen and oxygen, the word elements on a carbon skeleton with trace elements making it the rest. At the molecular level, we mostly water with fats, proteins and minerals making up the remainder. At the cellular level, where you predominantly cell mass, extra cellular solids, that's ECS, that ECF is extra cellular fluids and fat. And functionally, which we're most often interested is joint modify is muscle and fat, and then other substances like blood and bone. So within the functional assessment of body composition, there are a number of different models that can be used to describe body composition. As we can see, whether we're using a two, three or four component model, the common factor is fat mass. So different techniques are required for different analyzes, but most techniques can identify fat mass or a fat percentage analysis. So while fat is a common denominator between these different assessments of body composition, there are still different types of fat. So optimal fat is critical for optimal health. It is necessary for healthy cell and system function. At the minimum, it's 3% for men and 12% for women. Fat can be stored under the skin, known as subcutaneous or visceral fat, and deeper fat around the organs. It's the visceral fat that can be the dangerous for health due to its proximity to the organs. Here are a number of different ranges for recommended levels of body fat, but broadly speaking and optimum body fat percentage could be generalized to be between eight and 35% if you're unsure what these different levels of body fat look like, This slide provides a rough depiction of how body shapes change with increasing levels of body fat. For similar levels of body fat percentage, there are different fat distributions referred to as Android fat, or going away fat core locally there's the apple or pear body shape. The Android shape is more associated with health risk as the fat is stored around the organs. So humans are becoming increasingly overweight innovative. This is due to a number of reasons, but it can be summarized simply, as we are consuming more of energy. As wealth increases and high energy convenience foods become more prevalent, we're also burning less and less energy as tasks which were typically performed manually and burned like calories, and they are performed by technology machines. So this combination of more energy being consumed and less being burned has resulted in an explosion in obesity that's particularly in wealthy first world countries, and with that, an increase in preventable chronic diseases. So as many physical characteristics, there is a genetic component, and there are rare forms of obesity that are result of gene mutations which influence appetite or energy homeostasis. However, given that human genetics have changed little in the past 50 years, and obesity rates have increased significantly, the impact of genes on obesity are quite small. Instead, lifestyle choices driving the change in obesity rates, the magnitude of chronic health conditions associated with obesity are large, expensive and largely preventable, so being overweight has been demonstrated to impact cardiovascular disease, cancer, high blood pressure, hypertension and type two diabetes. Type Two Diabetes is a situation where the body becomes resistant to insulin. Type one diabetes is an unable genetic condition that usually in young people, where the body cannot produce insulin. Being overweight or obese can impact sleep as we naturally, plays a critical role in physical and mental health. However, it's not only being overweight that has health implications. Being underweight can also carry significant risks. In women, it can lead to menstrual abnormalities and associated health complications with that. In women, it can lead to osteoporosis. So that's a condition characterized by weaker bones, which makes it more susceptible to fracture. But physiologists and dietitians can calculate metabolic rate using equations to determine the basal metabolic rate, that's the minimum energy required to maintain physiological function, so it is dependent upon age, gender and body mass. Resting metabolic rate can still be calculated, and it's similar, but it's measured under different conditions. This is important because knowing the metabolic rate consists professionals to prescribe nutrition and exercise, inventions to manage body composition. So once we know roughly how much energy a person needs to function at rest, we can apply an activity factor to this BMR to determine daily energy requirements, in total, to maintain weight, and use this as a guide to monitor nutritional intake, to manage weight. So in summary, body composition is the compartmentalization of body tissues. Body fat is essential for health, but there is an optimal range and lifestyle choices impact body composition. So overweight and obesity has a range of adverse health risks, and likewise, underweight is also the health risk. Exercise professionals look at the energy requirements and we can calculate those to help us by nutrition and exercise interventions to help people with weight, composition. ANTHROPOMETRY we will build on understanding of body composition and the means available for body composition assessment. By the end of this lecture today, you will understand how to measure and interpret body composition using both field and lab based methods. So assessment methods for many physical tests, including anthropogenic can be divided into field based tests and lab based tests. Generally speaking, field tests are more simple, quicker and cheaper to administer, but can lack the accuracy and sometimes the detail of lab methods. Lab methods, on the other also, are far more accurate, of the more expensive compared to field tests have much tighter testing protocols involving more time, and they make them more challenging to administer to administer. Two groups, we'll go through some of these assessments. Now, with all testing, there are protocols to ensure there are reliability to test. So for height and weight, an example would be weighing someone with shoes off for the first time and then shoes on the next time will result in increasing weight. That's the weight of their shoes, but we could mistakenly conclude that they'd increase weight. So an easy way to avoid confusion with all their testing protocols is to have standardized testing. So with for height, we would remove shoots, we would stand straight and have the feet together. On this last point, think about the difference in height of a couple of centimeters, and the difference between your feet together and your feet wide apart. For body weight, ideally, your point is in minimal clothing, which is not always convenient or comfortable, but something that we should consider for if we're doing some athlete populations, particularly swims or water ball athletes, we're trying to get them with straight from the pool where they have weight here, because that would affect the measurement as well. Body mass index, or BMI, is a common method to non invasively assess body composition in terms of overweight and absent, using just height and weight. So it is based on the concept that individuals with lower body fat will have a lower BMI. However, that's not always accurate in the sense that a heavily muscular athlete can appear overweight or even obese, although they have a metabolically healthy tissue in terms of they have a lot of muscle mass. So here is an example of a classification table which outlines for adults, normal BMI, overweight, obesity and severe obesity would be based upon that relationship of height and weight. Though there's an illustration as discussed in BMI, it's very well researched, and there is really strong relationships between BMI and health complications, such as diabetes, hypertension, coronavisis, heart disease. So colitheasis is the formation of gallstones and hardened deposits within the fluid of the gallbladder, which is small organ under liver, Corona heart disease. So that's CHD. So this BMI chart doesn't even show obesity, which is a BMI over 30 under the risk of higher BMI through the range of normal and overweight as alluded to, BMI is a pretty useful tool for measuring antibiotic at the population level, as for most people, weight increases with percentage of body fat. However, it doesn't directly measure fat mass. Therefore at an individual level, it might not, might not necessarily be a great measure. So for example, if you lose three kilograms of muscle and gain three kilograms of fat to body mass index, let's say very muscley individuals are often considered overweight or obese, and the elderly can have non representative BMI due to age associated muscle atrophy or decreasing height. It's important to know the limitations of tests, as they will influence your interpretation and interventions. This involves another very common method to assess body fat. They are very important to measure. They are reliable and valid. However, they become slightly invasive because it provides some touching but there are a range of sites that can be used to make the testing a little bit more comfortable. It involves measuring the two layers of subcutaneous fat beneath the skin, and it can provide an estimation of some overall fatness. I talked about reliability. It can have a small error. There's small error associated with every test, but the more you practice, and if you're likely credited level one anthropometrist, you've practiced enough that your error is acceptably low. There's a number of different summation sites. You have seven sites, which provides a good overall view of the body, but sometimes it might only be three or four sites, and sometimes there's an site model as well. We'll be practicing involved in the lab. Whilst it appears a fairly straightforward practice, it is important to practice to get a feel of, first of all, to get an accurate landmark, because there are specific sites that we take a measure. Then also to get a feel of what an appropriate pinch is. So we don't get sometimes it's easy to pinch the muscle inside the sample, which gives it a bigger ring in a lower ring. And if all measures are always taken on the right side of the body, where they can, ideally, we carefully measure and mark the site with a permanent marker. I grabbed this info between the thumb, index finger, just to get a slight fold. We replace the calipers just below that pinch, hold for two seconds and then release. And we do multiple measures at the same site to get valid readings. Some of the sites that we take would be the medzilla, the abdominal, the thigh, triceps and biceps, and it's also subscapular, suprailiac, medial calf, and suppress Mala so there are several methods by the number of different sites, whether it's 34678, and each different summation has a conversion to body fat percentage. So it depends on the number of access sites you have. Some can be uncomfortable for some people. So then you have different samples that you can use to know that the formulas give you body density, but you need to use the serum equation to convert percent with a series a published researcher from the 60s, and it's not the Apple program on your phone. Here are some other methods that you can use to value to test my body fat. So based on the clients that you work with or the sporting organization, they may have a different protocol. So it's important that you're familiar with one specific requirements, and also important that you keep using the same protocol. You cannot compare a three site to a seven site. You compare the three side to three side, or a seven side to seven side. As far as assessments go, gith measurement is about as basic as it can get. However, the power and the surface of the test, it's easy to learn, it's easy to administer. It inexpensive, and the value of information and the relationships to health, it's actually a really good test. As well as the waste, there's also a full body assessment, which will involve measuring other areas. So it's really important to practice these you're entering someone else's physical zone. You're touching. It's a minimal touch, but you're still touching. So whilst trying to accurately place a tape and read small writings, it can be quite challenging, so it's really important to practice these you can also measure a mid thigh, thigh, forearm and cut. I stated earlier there was a waist to hip ratio, and given the low cost of the test, information value is incredibly high. Higher scores of waste relative to keep circumference indicates higher abdominal fat, which is an increased risk of cardiovascular disease, and that's the android or apple shape that we talked about in the previous lecture. There are optimal ranges, and there's risk related to waste to heat ratios. So this is some really important information for such a non invasive and simple test, but also laboratory tests which become more complicated and provide more detailed information. So these include the scans hydrostatic weight, air displacement and biological impedance, which we'll go through now. So a dual energy X ray, or DEXA, is a low radiation X ray scan of the entire body, which can estimate body fat and bone density. It has mass less radiation than an x ray, and it's able to identify fat and bone and it can actually provide excellent detail on fat mass and really important information on bone density. So that bone density so that bone density information is quite important for specific populations. It could also be done in conjunction with a more frequently performed field test. There's a comparison, because it's expensive for them and requires professional expertise. For example, The Sporting Club might do one test in their preseason as a really detailed assessment. At the same time, they'll do skin folds, and they'll use that skin fold comparison to Dexter skin to track their athletes with multiple skin fold assessments throughout the season. Hydrostatic weighing. This is where the subject is weighed on land, and then when they land fully submerged in water, and relies on the difference between underwater and out of water weights and the density of the body and water displacement. This is not as popular due to the non population scans, due to the inconvenience of being weighed underwater, and it requires the specialized equipment that subject must also exhale or their air and then remain underwater, which makes it a somewhat difficult process. There's also air displacement, which was used to overcome the need to submit some of the water, and also calculated based upon weight and air displacement. But again, it's less popular test because it's time consuming and expensive. And finally, we have bio electrical impedance analysis. Now, whilst you could argue that this is a field measure rather than a lab measure, it does require a specialized piece of equipment. So that's what's included here. This is where a low level current is passed through the body to estimate the body fat percentage, given that lean tissue contains more water than fat tissue, the level of resistance to the current, indicating that lean versus fatness. This is certainly much cheaper than other lab based methods that's not as reliable and only provides a general measure of body composition. It could also be influenced by hydration status and even moisture on hair and clothes. So whilst we understand we try standardize all our tests, we can see that there's more errors can be introduced into a b by a test. So in summary, body composition can be assessed by field or lab tests. The field tests are cheaper, they're quicker and but they're less accurate than lab the lab much more accurate, much more detailed, but they can be expensive. They're also prohibitive for large groups, because the time requirements for the streets protocols, BMI home weight only, and that has a great relationship to health risk. So does he have to weight ratio, girth OS detects remains the gold standard for body composition. It is a little more expensive regarding specialized equipment and harder to get body composition. Assessment for exercise and sports science professionals is a really important tool in the assessment toolbox, and this will form part of our labs where we get a lot of hands on experience, learning how to do girths and skin vaults, learning to I'm encourage you to be involved in the lab as much as possible, to practice these skills. Thank you for listening to today's lecture if you have any questions, please ask your tutors or send His names. Thanks
Updated 14d ago
flashcards Flashcards (5)
Constants
Updated 20d ago
flashcards Flashcards (15)
0.00
studied byStudied by 0 people