Results for "zygote"

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

Zygote

post vs pre zygote isolation

Let’s break this down! I’ll give you a study guide covering asexual reproduction, sexual reproduction (in humans and plants), and Mendelian genetics — then I’ll create a test for you. ⸻ Study Guide for Asexual Reproduction, Sexual Reproduction, and Mendelian Genetics ⸻ I. Asexual Reproduction • Definition: Involves a single parent, producing offspring genetically identical to the parent (clones). • Types of Asexual Reproduction: • Binary Fission: Simple cell division (e.g., bacteria). • Budding: New organism grows from a bud on the parent (e.g., yeast, hydra). • Fragmentation/Regeneration: Organism splits, and each part grows into a new organism (e.g., starfish). • Vegetative Propagation: New plants grow from parts of the parent plant (e.g., runners in strawberries). • Parthenogenesis: Offspring develop from unfertilized eggs (e.g., some lizards, insects). • Pros and Cons: • Pros: Fast, no need for a mate, energy-efficient. • Cons: No genetic variation, susceptible to environmental changes. ⸻ II. Sexual Reproduction (Humans & Plants) Humans: • Process: • Gametes (sperm and egg) produced by meiosis. • Fertilization forms a zygote (diploid cell). • Male Reproductive System: Testes, epididymis, vas deferens, prostate, urethra, penis. • Female Reproductive System: Ovaries, fallopian tubes, uterus, cervix, vagina. • Hormonal Regulation: • Male: Testosterone (sperm production, secondary characteristics). • Female: Estrogen & progesterone (menstrual cycle, pregnancy). Plants: • Process: Alternation of generations (sporophyte & gametophyte stages). • Pollination: Transfer of pollen to stigma. • Fertilization: Sperm (from pollen) fuses with egg in ovule. • Structures: Stamen (male), carpel/pistil (female). • Seed & Fruit Development: Fertilized ovules become seeds; ovary becomes fruit. ⸻ III. Mendelian Genetics • Gregor Mendel’s Experiments: Pea plants, discovered inheritance patterns. • Key Concepts: • Genes & Alleles: Genes determine traits, alleles are gene variants. • Dominant vs. Recessive Alleles: Dominant alleles mask recessive ones. • Homozygous vs. Heterozygous: Same alleles (AA or aa) vs. different alleles (Aa). • Laws of Inheritance: • Law of Segregation: Allele pairs separate during gamete formation. • Law of Independent Assortment: Genes for different traits sort independently. • Genetic Crosses: Punnett squares, monohybrid/dihybrid crosses. • Probability & Ratios: Phenotypic/genotypic ratios. • Non-Mendelian Inheritance: Incomplete dominance, codominance, multiple alleles, polygenic traits, sex-linked traits. ⸻ AP Biology Practice Test Total Questions: 30 (Multiple Choice) Section 1: Asexual Reproduction (6 questions) 1. Which form of asexual reproduction involves an organism splitting into two identical cells? a) Budding b) Fragmentation c) Binary fission d) Parthenogenesis 2. Which organism commonly reproduces through budding? a) Bacteria b) Starfish c) Hydra d) Fern 3. A disadvantage of asexual reproduction is: a) Slow reproduction rate b) High genetic diversity c) Vulnerability to environmental changes d) Requirement of a mate 4. Which plant structure is involved in vegetative propagation? a) Petal b) Stigma c) Runner d) Anther 5. Parthenogenesis involves: a) Fertilized eggs developing into offspring b) Unfertilized eggs developing into offspring c) Fusion of gametes d) Regeneration of lost body parts 6. What is the primary benefit of asexual reproduction in stable environments? a) Genetic variation b) Rapid population growth c) Evolutionary adaptability d) Reduced mutation rates ⸻ Section 2: Sexual Reproduction (8 questions) 7. In humans, fertilization typically occurs in the: a) Uterus b) Vagina c) Ovary d) Fallopian tube 8. The male gamete in plants is contained in the: a) Ovule b) Anther c) Pollen grain d) Stigma 9. Which hormone triggers ovulation? a) Testosterone b) Progesterone c) Luteinizing hormone (LH) d) Estrogen 10. The female gametophyte in flowering plants is the: a) Ovary b) Pollen tube c) Embryo sac d) Sepal 11. Which part of the male reproductive system produces sperm? a) Epididymis b) Vas deferens c) Testes d) Prostate gland 12. The process where pollen is transferred from anther to stigma is: a) Germination b) Pollination c) Fertilization d) Sporulation 13. What structure develops into a seed after fertilization in plants? a) Ovule b) Ovary c) Stamen d) Pistil 14. Which term describes the fusion of egg and sperm to form a zygote? a) Gametogenesis b) Meiosis c) Fertilization d) Pollination ⸻ Section 3: Mendelian Genetics (16 questions) 15. Who is considered the “Father of Genetics”? a) Charles Darwin b) Gregor Mendel c) Rosalind Franklin d) James Watson 16. The physical expression of a trait is called: a) Genotype b) Phenotype c) Allele d) Chromosome 17. An organism with the genotype Aa is: a) Homozygous dominant b) Homozygous recessive c) Heterozygous d) Diploid 18. A Punnett square shows: a) The process of DNA replication b) Possible genetic combinations of offspring c) Chromosome number in gametes d) Evolutionary relationships 19. The expected phenotypic ratio for a monohybrid cross is: a) 1:2:1 b) 9:3:3:1 c) 3:1 d) 4:0 20. Which of Mendel’s laws states that allele pairs separate during gamete formation? a) Law of Independent Assortment b) Law of Segregation c) Law of Dominance d) Law of Inheritance 21. Incomplete dominance results in: a) Blended traits b) Both traits expressed equally c) One trait completely masking another d) A 9:3:3:1 ratio 22. A cross between two heterozygous individuals (Aa x Aa) produces what genotypic ratio? a) 3:1 b) 1:2:1 c) 9:3:3:1 d) 2:2 23-30

Immune System Study Guide Function of the Immune System Main Function: The immune system protects the body from harmful invaders (pathogens like bacteria, viruses, fungi, etc.) and detects and eliminates abnormal cells.Detects and destroys foreign invaders . Yngv Memory: The immune system has the ability to "remember" past infections, allowing it to respond more quickly to the same pathogen if encountered again.Maintains a memory of past infections to mount a quicker response if the same pathogen attacks again. Types of Immunity Innate Immunity: The immune system you're born with; provides a quick response to any pathogen. First line of defense: Skin and mucus act as physical barriers. Macrophages: Large white blood cells that "eat" pathogens and activate other immune cells. Histamine & Inflammation: Histamine triggers inflammation to fight infection (redness, heat, swelling, pain). Adaptive Immunity: Develops over time and strengthens with repeated exposure to pathogens. B-cells: Produce antibodies that specifically target pathogens. T-cells: Help destroy infected cells or coordinate the immune response. Memory Cells: "Remember" past infections for faster responses in the future. Innate immunity is something you're born with and provides a quick response to any pathogen. Adaptive immunity develops over time, adapting to new threats. It includes things like antibodies and memory cells. Signs of Inflammation Redness (rubor): Increased blood flow to the affected area. Heat (calor): Blood flow increases temperature at the site. Swelling (tumor): Fluid accumulation and immune cells moving to the area. Pain (dolor): Due to chemicals irritating nerve endings. Loss of Function (functio laesa): Temporary loss of function in the inflamed area. Bacteria vs. Viruses feature bacteria viruses size bigger smaller Can live without a host? yes no Good or bad Some are helpful Always harmful treatment Antibiotics kill them No antibiotics, only vaccines or immune system fights them examples Strep throat Flu, COVID-19 Antibiotic Resistance Occurs when bacteria evolve to resist antibiotics. Reasons for Resistance: Overuse or misuse of antibiotics. Using antibiotics for viral infections. Self-medicating without proper diagnosis. Vaccines What Are They?: Biological preparations that provide immunity against specific diseases. How Do They Work?: Contain weakened or inactivated parts of a pathogen to stimulate an immune response. Importance: Vaccines teach the immune system to recognize pathogens and fight them effectively in the future. They also contribute to herd immunity. Reproductive System Study Guide Male Reproductive System Testes: Produce sperm and the hormone testosterone. Epididymis: Stores sperm until they mature. Vas Deferens: Transports sperm from the testes to the urethra. Prostate Gland & Seminal Vesicles: Produce fluids that nourish and transport sperm. Penis: Delivers sperm into the female reproductive tract during ejaculation. Female Reproductive System Ovaries: Produce eggs (ova) and hormones like estrogen and progesterone. Fallopian Tubes: Transport eggs from the ovaries to the uterus; fertilization typically occurs here. Uterus: Where a fertilized egg implants and develops during pregnancy. Cervix: The lower part of the uterus that connects it to the vagina. Vagina: The passage that receives sperm and also serves as the birth canal. Conception and Pregnancy Conception: Occurs when sperm fertilizes an egg in the fallopian tube, forming a zygote, which then implants in the uterus. Pregnancy: The zygote develops into an embryo and then a fetus in three trimesters: First Trimester (Weeks 1-12): Organ development begins; the heart starts to beat. Second Trimester (Weeks 13-26): Rapid growth; organs mature and gender can be determined. Third Trimester (Weeks 27-Birth): The fetus continues to grow; organs mature, especially the lungs. Factors Affecting Baby Development Environmental factors: Exposure to toxins, pollutants, drugs, or infections. Nutrition: Essential nutrients are crucial for healthy fetal development. Health conditions: Chronic conditions like diabetes or hypertension can affect pregnancy. Types of Contraception Barrier Methods: Condoms (Male & Female): Prevent sperm from reaching the egg and protect against STDs. Pros: Easy to use, no side effects, protects against STDs. Cons: Must be used correctly every time; can break or slip off. Diaphragm with Spermicide: A barrier placed in the vagina to cover the cervix. Pros: Non-hormonal, on-demand use. Cons: Requires fitting, not effective without spermicide. Hormonal Methods: Birth Control Pills: Prevent ovulation through hormones like estrogen and progesterone. Pros: Highly effective, can regulate periods, reduces acne. Cons: Must be taken daily, side effects like nausea or headaches. Patch: Worn on the skin to release hormones. Pros: Easy to use, weekly change. Cons: Visible, may cause skin irritation. Implant: A small device placed under the skin to release hormones. Pros: Long-lasting (up to 3 years), effective. Cons: Requires professional insertion, can cause irregular bleeding. IUD (Intrauterine Device): A device inserted into the uterus to prevent fertilization. Pros: Long-lasting (5-10 years), effective. Cons: Requires professional insertion, may cause cramping. Permanent Methods: Vasectomy (Male): Cutting and sealing the vas deferens to prevent sperm from reaching the urethra. Tubal Ligation (Female): Cutting or sealing the fallopian tubes to prevent eggs from reaching the uterus. Pros: Permanent, highly effective. Cons: Surgical procedures, irreversible, not suitable for those wanting future children. Emergency Contraception: Morning-After Pill: Taken after unprotected sex to prevent pregnancy. Pros: Available over-the-counter, effective within 72 hours. Cons: Not for regular use, may cause side effects. Copper IUD: Can be inserted up to 5 days after unprotected sex to prevent pregnancy. Key Takeaways Immune System: It provides a defense against infections, relying on both innate (immediate) and adaptive (long-term) immunity, with important components like macrophages and memory cells. Vaccines are essential in helping the immune system recognize pathogens and prevent diseases. Reproductive System: Male and female systems work together to ensure conception and pregnancy, with critical stages of fetal development occurring in the three trimesters. Environmental factors and health conditions can impact pregnancy. Contraception Methods: There are various types, each with its pros and cons, including barrier methods, hormonal methods, and permanent methods. Choosing the right method depends on individual needs, effectiveness, and side effects. Histamine & Inflammation: Histamine release can cause redness, warmth, and swelling as part of the body's inflammatory response to infection or injury. Vaccines & Herd Immunity: Vaccines are critical in preventing the spread of infectious diseases by "teaching" the immune system to recognize and fight specific pathogens. Herd immunity occurs when a large portion of a population is vaccinated, making it harder for diseases to spread. Components of the Immune System: Defense against pathogens: The immune system helps protect the body from harmful invaders like bacteria, viruses, fungi, and parasites. Recognition of abnormal cells: It identifies and eliminates cells that are infected or cancerous Key Defense Lines: First Line of Defense: Skin & mucus trap and kill germs. Second Line of Defense: Inflammation and macrophages (eat germs). Third Line of Defense: T-cells destroy infected cells, B-cells make antibodies to target germs

CT4-LECTURE 1- JAN 2025 OBJECTIVES Developmental Anatomy (Embryology): • Outline the stages of human growth and development, focusing on dental anatomy and root morphology. • Correlate developmental processes with hard and soft tissue formation in the oral cavity. Microscopic Anatomy: • Classify cells (cytology) and tissues (histology) based on their structure and specialization. • Evaluate the role of microscopic structures in maintaining oral health. GROSS Anatomy • Identify anatomical landmarks of the oral head and neck, including the TMJ, circulatory system, glands, and nervous system. • Describe the structures visible to the naked eye and their clinical relevance. Physiology: • Explain the functions of body systems and their integration in oral health. • Analyze the physiological processes affecting the oral cavity. 1/16/2025 3 Mitosis Meiosis One cell division Two cell division Produces two daughter cells Produces Four daughter cells Produces diploid cells Produces haploid cells Daughter cells are genetically identical Daughter cells are non- identical Produces body cells Produces sex cells • Mitosis and meiosis are both types of cell division. • Mitosis is how new body cells are produced, whereas meiosis is used to produce gametes (i.e. sperm and egg cells). first week Spermatozoa + Oocyte = Zygote (12-24hrs.) Cell division via mitosis = Cleavage 1st solid ball called Morulla Inside Morulla secretion of fluids becomes blastocyte (5days) Blastocyte has 2 regeions Trophoblast(peripheral cells) & Embryoblast layer(inner mass) CLINICAL CONSIDERATIONS FOR PREIMPLANTATION PERIOD •If any disturbances occur in meiosis during fertilization, major congenital malformations result from the chromosomal abnormality in around 10% of cases. •A syndrome is a group of specific signs and symptoms. PREIMPLANTATION PERIOD • After a week of cleavage, the blastocyst consists of a layer of peripheral cells, the trophoblast layer, and a small inner mass of embryonic cells or embryoblast layer. • The trophoblast layer later gives rise to important prenatal support tissue while the embryoblast layer later gives rise to the embryo. SECOND WEEK • A bilaminar embryonic disc • The superior epiblast layer is composed of high columnar cells. • The inferior hypoblast layer is composed of small cuboidal cells. THIRD WEEK • Primitive streak (rod shaped thickening) forms a bilateral symmetry within the bilaminar embryonic disc. • Some cells from the epiblast layer move or migrate toward the hypoblast layer only in the area of the primitive streak and become • Mesoderm, an embryonic connective tissue, and embryonic endoderm. END OF THIRD WEEK • With three layers present, the bilaminar disc has thickened into a trilaminar embryonic disc. • The epiblast layer is now considered ectoderm. • 3 germ layers • Ectoderm-becomes skin, nervous system, and neural crest cells. • Mesoderm-Becomes muscles, bones, blood, and connective tissues. • Endoderm-Forms internal organs like the digestive and respiratory systems. 1/16/2025 10 Neural Crest Cells & Mesenchymal Transition(dental tissue) • Neural crest cells are derived from the ectoderm during neurulation (around weeks 3-4). • NCC migrate and undergo epithelial-to-mesenchymal transition (EMT), becoming highly migratory mesenchymal cells. • They contribute to the formation of facial bones, cartilage, peripheral nerves, and parts of the heart. 1/16/2025 11 Embryonic Period: Physiological Process(changes in structure &function) • INDUCE, PROLIFERATE, DIFFERENTIATE AND MORPH, DON’T WAIT! MATURE AND GROW, IT’S YOUR FATE!" 1. Induction The process where one group of cells influences another to differentiate into a specific tissue or organ. 2. Proliferation Rapid cell division, increasing the number of cells. 3. Differentiation(Cyto, Histo, Morpho) Cells specialize to perform specific functions. 4. Morphogenesis The development of the overall shape and structure of tissues and organs. 5. Maturation The final stage where tissues and organs reach their fully functional form. 1/16/2025 12 Facial Development  The facial development that starts in the fourth week of the embryonic period will be completed later in the twelfth week within the fetal period.  At the fourth week, the developing brain, face, and heart are noted. 1/16/2025 13 • All three embryonic layers are involved in facial development: the ectoderm, mesoderm, and endoderm. • The upper part of the face is derived from the frontonasal process, the midface from the maxillary processes, and the lower from the mandibular processes. Early development of the face is also dominated by the proliferation and migration of ectomesenchyme, derived from neural crest cells (NCCs). Facial Development 1/16/2025 14 Stomodeum and Oral Cavity Formation With this disintegration of the membrane, the primitive mouth is increased in depth and enlarges in width across the surface of the midface. Nose and Paranasal Sinus Formation Apparatus Formation  First branchial/ pharyngeal arch also known as the mandibular arch and its associated tissue, includes Meckel cartilage.  Supplied by Trigeminal nerves Apparatus Formation  Second branchial/pharyngeal arch, which is also known as the hyoid arch, is cartilage like that of the mandibular arch, Reichert cartilage. Apparatus Formation  Third branchial/ pharyngeal arch  Has an unnamed cartilage associa ted with it. This cartilage will be responsible for forming parts of the hyoid bone. Apparatus Formation  Both the fourth and the sixth branchial /pharyngeal arch also have unnamed cartilage associated with them, they fuse and form most of the laryngeal cartilages. 1/16/2025 20 TOOTH DEVELOPMENT: INITIATION STAGE Stages of Tooth Development: I Bought Candy Bars After Midnight." I → Initiation Bought → Bud Candy → Cap Bars → Bell After → Apposition Midnight → Maturation 1/16/2025 23 1. Initiation Stage (Week 6-7): • Dental placodes form as localized thickenings of oral ectoderm. • Interaction with neural crest cells induces the formation of the tooth germ. 2. Bud Stage (Week 8): • The enamel organ invaginates into the underlying mesenchyme, creating a tooth bud. 3. Cap Stage (Week 9-10): • The enamel organ forms a cap-like structure over the dental papilla. 4. Bell Stage (Week 11-12): • Cells differentiate into ameloblasts (enamel-forming cells) and odontoblasts (dentin-forming cells). 5. Apposition and Maturation: • Enamel, dentin, and cementum are laid down and mineralized. 1/16/2025 25 • Dental Epithelium → Enamel Organ Enamel organ arises from the dental epithelium and forms ameloblasts, the cells responsible for producing enamel, the hardest substance in the body. Dental Mesenchyme → Dental Papilla Dental papilla forms from the mesenchyme and gives rise to: • Dentin -Odontoblasts: Cells that produce dentin (the layer beneath enamel). • Pulp: The soft, living core of the tooth, containing nerves and blood vessels. • Root Dentin: The dentin in the root of the tooth. Dental Follicle • Surrounds the developing tooth and forms: • Cementum: A calcified tissue covering the root of the tooth, anchoring it to the jaw. • Periodontal Ligament: Connective tissue fibers that hold the tooth in its socket and absorb chewing forces. Teeth w e a r c a n b e t r e a t e d A t t r i t i o n Abrasion Abfraction E r o s i o n Hunter-Schreger bands (HSB). • Hunter-Schreger bands (HSB): • Dark and light bands due to curvature or bends of the rods. • increasing the enamel’s strength. • Near the cusps or incisal ridges, where the enamel is the thickest Celiac Disease ˜ Dental enamel problems stemming from celiac disease involve permanent dentition and include tooth discoloration—white, yellow, or brown spots on the teeth—poor enamel formation, pitting or banding of teeth, and mottled or translucent-looking teeth. ˜ The imperfections are symmetrical and often appear on the incisors and molars. ˜ Tooth defects that result from celiac disease may resemble those caused by too much fluoride or a maternal or early childhood illness 1/16/2025 29 ROOT DEVELOPMENT  The process of root development takes place long after the crown is completely shaped, and the tooth is starting to erupt into the oral cavity.  The structure responsible for root development is the cervical loop.  The cervical loop is the most cervical part of the enamel organ, a bilayer rim that consists of only inner enamel epithelium (IEE) and outer enamel epithelium (OEE). ROOT DEVELOPMENT  To form the root region, the cervical loop begins to grow deeper into the surrounding ectomesenchyme of the dental sac, elongating and moving away from the newly completed crown area to enclose more of the dental papilla tissue, forming the Hertwig epithelial root sheath (HERS). Thus, HERS will determine if the root will be curved or straight, short or long as well as single or multiple. 1/16/2025 33 • Cervical Loop Formation ▪ The cervical loop, located at the junction of the enamel organ and the crown, elongates to form Hertwig’s Epithelial Root Sheath (HERS). ▪ HERS determines the shape, length, and number of roots. • Root Dentin Formation ▪ Inner cells of HERS induce adjacent dental papilla cells to differentiate into odontoblasts, which form root dentin. ▪ Once dentin is deposited, HERS disintegrates. • Epithelial Rests of Malassez ▪ After HERS disintegrates, remnants form clusters called epithelial rests of Malassez in the periodontal ligament. ▪ These remnants can sometimes form cysts later in life. PRIMARY DENTITION PROPERTIES  The actual dates are not as important as the eruption sequence, because there can be a great deal of variation in the actual dates of eruption.  However, the sequence tends to be uniform. Enamel Histology • Enamel tufts: Hypomineralized, Located at the dentino-enamel junction and filled with organic material. Forms between groups of enamel rods at the dentino-enamel junction. • Enamel lamellae are partially mineralized vertical sheets of enamel matrix that extend from the DEJ near the tooth’s cervix to the outer occlusal surface. Transverse section of enamel showing enamel tufts (white arrow) and enamel lamella (black arrow). Dentin Matrix Formation DENTINOGENESIS LPROCESS o$ CREATING DENTIN PRIMARY TEETH _ 14th WEEK of FETAL DEVELOPMENT PERMANENT TEETH L 3 MONTHS AFTER -PROCESS HAPPENS SLOWLY PERFORMED by ODONTOBLASTS —OUTSIDE INWARDS - BEGINS with MANTLE DENTIN ODONTOBLASTS -PREDENTIN -SOFT ORGANIC MATRIX -PROTEINS FIBROBLASTS -KORFF'S FIBERS -THICK COLLAGEN FIBERS -FRAMEWORK of DENTINOGENESIS 1/16/2025 39 Principal Fibers Protect, Gingival Fibers Guard." •Principal → Protection and anchorage of the tooth. •Gingival → Guard and stabilize gingiva. 1/16/2025 40 Principle Fibers "All Hungry Octopuses Appreciate Ice cream!" •All → Alveolar Crest •Hungry → Horizontal •Octopuses → Oblique •Appreciate → Apical •Ice cream → Interradicular 1/16/2025 41 Gingival Fiber : "Dentists Always Care Deeply for Teeth!" •Dentogingival •Alveologingival •Circular •Dentoperiosteal •Transseptal 1/16/2025 42 Primary (Deciduous) Teeth Eruption "Children Like Fruit Candy More" •C → Central Incisors •L → Lateral Incisors •F → First Molars •C → Canines •M → Second Molars CELL ORGANELLES SKIN ANATOMY COME, LET'S GET SOME BREAD" C ORNEUM (OUTER), L UCIDUM, G RANULOSUM, S PINOSUM, B ASALE. • Corneum - tough and protective. • Lucidum - clear layer (found only in thick skin like palms/soles). • Granulosum - cells with granules for keratinization. • Spinosum - "spiny" cells, providing strength and flexibility. • Basale - base layer where cell division happens. 1/16/2025 45 1/16/2025 46 Tooth Designation ∙ Commonly used in orthodontics, is the Palmer Notation Method, also known as the Military Tooth Numbering System. ∙ In this system, the teeth are designated from each other with a right-angle symbol indicating the quadrants and arch, with the tooth number placed inside. 1/16/2025 47 Mixed Dentition Period ∙ The mixed dentition period follows the primary dentition period. ∙ This period occurs between approximately 6 and 12 years of age. ∙ Both primary and permanent teeth are present during this transitional stage. ∙ The final dentition period is the permanent dentition period. ∙ This period begins with shedding of the last primary tooth. 1/16/2025 48 General Dental Terms •Each dental arch can be further divided into two quadrants, with four quadrants in the entire oral cavity. • The correct sequence of words when describing an individual tooth using a D-A-Q-T System is based on the tooth within its quadrant: D for dentition, A for arch, Q for quadrant, and T for tooth type. • Sextants: three parts according to the relationship to the midline: right posterior sextant, anterior sextant, and left posterior sextant. 1/16/2025 49 Root Axis Line (RAL) ∙ Root axis line (RAL), which is an imaginary line representing the long axis of a tooth, drawn in a way to bisect the root (and thus the crown) in the cervical area into two halves. 1/16/2025 50 Restorations: Biologic Width ∙ Biologic width is the distance established by the junctional epithelium and lamina propria attachment to the root surface of a tooth. ∙ This distance is important to consider when fabricating dental restorations, because they must respect the natural architecture of the gingival attachment if harmful consequences are to be avoided. ∙ Assessment for biologic width can be made clinically by measuring the distance between the bone and the restoration margin using a periodontal probe. 1/16/2025 51 PRIMARY DENTITION 1/16/2025 52 1/16/2025 53 Eruption 1/16/2025 54 1/16/2025 55 1/16/2025 56 Differences-(Enamel depth/pulp) 1/16/2025 57 Differences: Roots 1/16/2025 58 Importance of Primary teeth - PRIMATE Space 1/16/2025 59 Leeway Space 1/16/2025 Primary Occlusion 60 •Majority of children have Mesial step between distal of Primary 2nd molars. Mandibular 2nd molars are situated mesially than maxillary. •A smaller but still large group of children exhibit a flush terminal plane. The distal surfaces of the primary 2nd molars are even with each other. •A still smaller minority have a distal step. The mandibular 2nd molars are situated more distally than their maxillary counterparts. Thus, they form a distal step. 1/16/2025 Anatomy of Primary teeth 61 Incisors: resemble the outline of permanent counterpart except Primary do not have mamelons on the incisal ridge and there are no pits on the lingual surface. 1/16/2025 Primary Canines 62 Canines- resemble the outline of their permanent counterparts. The maxillary canine has a sharp cusp and appears especially wide and short. Maxillary Central and Lateral Incisors Central Incisors: • Larger overall; they are the widest teeth mesiodistally in the anterior maxillary arch. • Crown is more symmetrical and fan (mesiodistally wider compared to incisocervical length). • Lingual fossa is less pronounced. • Cingulum is well-developed and centered. • Root is shorter and more conical, with a blunt apex. • Rarely exhibit significant variation. Lateral Incisors: • Smaller and narrower mesiodistally than the central incisors. • Crown is less symmetrical and more rounded. • Lingual fossa is deeper, with more pronounced marginal ridges. • Cingulum is narrower and often slightly off-center to the distal. • Root is longer and thinner, with a more pointed apex. • Frequently display developmental variations (e.g., peg-shaped lateral incisors, congenitally missing). 1/16/2025 66 1/16/2025 67 1/16/2025 68 1/16/2025 69 CLASSIC TRAITS ➢ From the occlusal view, molar crowns taper from the buccal to the lingual EXCEPT for maxillary 1st molars. ➢ From the occlusal view, molar crowns taper distally; this allows more of the occlusal surface to be visible from the distal aspect than the mesial. ➢Maxillary molars have 3 roots: MB, DB, and lingual (palatal). The lingual root is usually the longest and the DB is the shortest. ➢ Mandibular molars have 2 roots: a long mesial root and a slightly shorter distal root. ➢ The root furcation on mandibular molars is close to the cervical line, making the root trunk shorter than on the maxillary molars. MAJOR AND MINOR CUSPS ➢In general, each cusp is formed from its own lobe. ➢Major cusps are large and well developed. ➢Minor cusps are less developed and have smaller proportions. They are less functional than the major cusps and may not always be present. ➢Supplementary cusp is very small and completely afunctional. They are rarely present. 1/16/2025 72 ➢First molars are the most highly developed and largest of the molars and more likely to have major, minor and supplementary cusps. ➢Both the 1st and 2nd maxillary molars have 4 major cusps but only 2 are visible from the buccal view. ➢The longest of the 4 major cusps are the ML, followed by the MB, DB, and the shortest DL (if present). 1/16/2025 73 • Molars (general: crowns larger, squarer, bear more cusps than any other tooth class, have multiple roots, 3rd molars sometimes mistaken for premolars) • Generally speaking, the maxilla molars go from largest to smallest (1st molar to 3rd molar) in size and morphology. The crowns generally have 4 cusps. • The 1st molar has three roots (two buccal and one lingual, which when seen from the buccal position the lingual root comes into view in the middle of the two buccal roots). The occlusal surface is described as a rhomboid in shape with 4 distinctive cusps. • Oblique ridge max molars only and transverse ridge one on max 2 on mandibular. • The 2nd molar has three roots but the two buccal roots are nearly parallel with each other and is described as heart shape in the occlusal view. • The 3rd molar has three roots present but the two buccal roots are often fused, and the outline of the occlusal surface is also described as a heart shape. The 3rd molar also shows greater developmental variation than either the 1st or • 3rd molars are often the tooth that is congenitally missing. All roots of the molars angle distally with respect to the major crown axes (White & Folkens 2005: 152). 1/16/2025 74 1/16/2025 75 Joint Movement ˜ Two basic types of movement of the mandible are performed by the TMJ and its associated muscles of mastication: ˜ a gliding movement and ˜ a rotational movement. 1/16/2025 76 • The muscles of mastication include the • Temporalis, • And Masseter, • Pterygoid muscles, medial and lateral. • These muscles are involved in mastication using these two movements. 1/16/2025 77 1/16/2025 78 TMD: Acute Episode • Trismus or the inability to normally open the mouth. • When the patient tries to close and elevate the mandible, the condylar heads cannot move posteriorly because both the bony relationships prevent this, and the muscles have become spastic. 1/16/2025 79 Overjet • Overjet is measured in millimeters with the tip of a periodontal probe, once a patient is in CO. • The probe is placed at 90°or at a right angle to the labial surface of a mandibular incisor at the base of the incisal ridge of a maxillary incisor. 1/16/2025 80 • Overbite is measured in millimeters with the tip of a periodontal probe after a patient is placed in CO. • The probe is placed on the incisal edge of the maxillary incisor at 90º or at a right angle to the mandibular incisor. • When the reverse is the case and the mandibular arch and its incisors extends beyond the maxillary arch and its incisors, it is causes an underbite. 1/16/2025 81 Lymph Nodes • The lymph flows (arrows) into the lymph node through many afferent vessels. (A is first comes in) • On one side of the node is a depression, or hilus, where the lymph through fewer vessels, or even a single efferent vessel. (E is Exit) • Primary or Secondary. • Region drains into primary nodes. • Primary nodes, in turn, drain into secondary nodes (or central nodes). Lymphatics: General Drainage pattern of body Right jugular trunk Left jugular trunk Enters venous system near junction of left subclavian vein and left internal jugular Thoracic duct Left side of head, neck, thorax, entire abdomen, pelvis, lower extremities Enters venous system near junction of right subclavian vein and right internal jugular Right side of head, neck, thorax *Lymphatic vessels are small and directly drain tissues and connect lymph nodes. *Lymphatic ducts are much larger, receive lymph from many lymphatic vessels, and drain into the venous system. 1/16/2025 83 Superficial Lymph Nodes of the Head (five categories) 1. Facial; lie along facial vein. 2 Superficial Parotid; superficial to parotid gland. 3. Anterior Auricular; anterior to external auditory meatus. 4. Posterior Auricular; posterior to external auditory meatus. 5. Occipital; lie in the occipital region. *Tissue drainage: buccal mucosa, skin of zygomatic and infraorbital regions, scalp, external ear, lacrimal gland Deep Lymph Nodes of Head (two categories) 1. Deep Parotid; lie deep in the parotid gland, superficial to the masseter muscle 2. Retropharyngeal; posterior to the pharynx at the level of the atlas (first cervical vertebrae). *Tissue drainage: parotid gland, paranasal sinuses, hard and soft palate, middle ear Superficial Cervical Lymph Nodes (4 categories) 1. Submental; inferior to the chin in the submental space. 2. Submandibular; along the inferior border of the mandible, superficial to the submandibular salivary gland 3. External Jugular; along the external jugular vein, superficial to the sternocleidomastoid muscle. 4. Anterior Jugular; along the anterior jugular vein, anterior to the sternocleidomastoid muscle. Tissue drainage: 1.Submental and submandibular; teeth and related tissues, apex and body of tongue, anterior hard palate, floor of mouth, lips, chin, sub- mandibular and sublingual glands, cheeks. 2. External and anterior jugular; superficial tissues in the anterior and posterior triangles. Deep Cervical Lymph Nodes (2 categories) 1. Superior Deep Cervical; lie along internal jugular vein, superior to the omohyoid muscle. *Jugulo-digastric- becomes enlarged when a palatine tonsil or the pharynx is involved in infection. 2. Inferior Deep Cervical; lie along internal jugular vein, inferior to the omohyoid muscle. *Jugulo-omohyoid-drains the submental region and base of the tongue. Additional Deep Cervical Nodes 1. Accessory; lie along accessory nerve 2. Subclavicular; lie along clavicle. *Tissue drainage: mostly secondary nodes 1/16/2025 88 Sequence of lymph nodes draining various tissues Most of face, scalp, ear, orbit, sinuses, nasal cavities Most maxillary and mandibular teeth and associated tissues, apex and body of tongue, floor of mouth, sublingual and submandibular glands, lips Maxillary third molars and associated tissues, base of tongue, pharynx, tonsils Tissue Primary nodes Secondary nodes Submental and submandibular nodes Facial, anterior auricular, retroauricular, occipital superficial and deep parotid, and retropharyngeal nodes Submandibular, deep cervical nodes Retropharyngeal, deep cervical nodes Neck and cervical viscera Superficial and deep cervical nodes Right jugular trunk Right subclavian vein Left jugular trunk Left subclavian vein Thoracic duct Endocrine-secrete substance into blood, examples-adrenal gland pituitary gland, thyroid gland Exocrine-secretes substance through a duct leading outside the body (digestive tract, skin). Examples- sweat glands, salivary glands, mucous glands, pancreas Where are the salivary ducts located intraorally? Parotid (Stensen) duct opening > Parotid Papilla. Submandibular (Wharton) duct opening Sublingual Caruncle. Plica Sublingualis Sublingual Caruncle Parotid Papilla Sublingual duct opening - Via Duct of Bartholin → Sublingual Caruncle. OR Via smaller Ducts of Rivinus > Plica Sublingualis. Thyroid and Parathyroid glands (endocrine) Thyroid: 1.Located inferior to the larynx along the sides of the trachea. 2. Has 2 lobes, connected by an isthmus. 3. Secrets thyroxin which influences metabolic rate Parathyroid: 1. Four small glands located on the posterior aspect of the thyroid gland. 2. Secrete parathyroid hormone, which regulates calcium and phosphate levels. Thymus 1. Located in the thorax and anterior region of the base of the neck, deep to the sternum and sternohyoid and sternothyroid muscles. 2. Involved in the maturation of T-cell lymphocytes 3. Shrinks in size with age Teeth and Periodontium Commonly Involved in Clinical Presentations of Abscesses and Fistulae 1. Abscess in maxillary vestibule or palate, 2. Penetration of nasal floor 3. Abscess in nasolabial skin region 4. Penetration into maxillary sinus 5. Abscess in buccal skin region 6. Abscess in mandibular vestibule 7. Abscess in submental skin region 8. Abscess in sublingual region → Any maxillary tooth (except maxillary canines for palate) • Maxillary central incisors → Maxillary canine → Maxillary molars • Maxillary or mandibular molars → Any mandibular tooth • Mandibular incisors → Mandibular molars with short roots superior to mylohyoid Teeth/Periodontium and Spaces Possibly Involved With Various Clinical Presentations of Cellulitus Location Space Involved Teeth/Periodontium Involved Infraorbital region Zygomatic region Buccal region Buccal space Maxillary premolars, and maxillary and mandibular molars Submental region Submental space Anterior mandibular teeth Submandibular region (unilateral) Submandibular space Posterior mandibular teeth Submandibular region (bilateral) Submental, sublingual Submandibular spaces Spread of mandibular dental infection Lateral cervical region Parapharyngeal space Spread of mandibular dental infection 4 major routes 1. Spread to the paranasal sinuses 2. Spread by the vascular system 3. Spread by the Lymphatic system 4. Spread by spaces Bacteria can spread through the blood from infected dental tissues to other areas. (1) An infected thrombus (blood clot) can travel as an embolus and spread infection. (2) Transient bacteremia (presence of bacteria in the blood) can occur during dental treatment. For example, a needle advanced too far during an attempt at PSA block can penetrate the pterygoid venous plexus after being inserted through infected tissue (needle track contamination). (3) The pterygoid venous plexus drains the dental tissues and communicates with the cavernous sinus via the inferior ophthalmic vein. (4) Infections in dental tissues can initiate an inflammatory response, which can result in thrombus formation, blood stasis, and increased extravascular pressure. (5) Veins in the head do not have valves, so backflow of blood carrying pathogens into the cavernous sinus can occur. Cranial Nerve Names & Function Names: "Only One Of The Two Athletes Felt Very Good, Victorious, And Healthy" Function: "Some Say Marry Money, But My Brother Says Big Brains Matter Most" 1. Only (Some) = Olfactory (S) 2. One (Say) = Optic (S) 3. Of (Marry) = Oculomotor (M) 4. The (Money) = Trochlear (M) 5. Two (But) = Trigeminal (B) 6. Athletes (My) = Abducens (M) 7. Felt (Brother) = Facial (B) 8. Very (Says) = Vestibulocochlear (S) 9. Good (Big) = Glossopharyngeal (B) 10. Victorious (Brains) = Vagus (B) 11. And (Matter) = Accessory (M) 12. Healthy (Most) = Hypoglossal (M) Blood Branching of Carotid Arteries from Aorta Common Carotid Arteries To upper limb Subclavian artery Subclavian artery Brachiocephalic trunk Aortic arch From heart To thorax, abdomen, legs Blood Flow LAB RAT LEFT ATRIUM=BICUSPID RIGHT ATRIUM= TRICUSPID Right ABC'S THE AORTIC ARCH GIVES RISE TO -BRACIOCHEPHALIC TRUNK COMMON COROTID ARTERY SUBCLAVIAN ARTERY Left: carotid & subclavian LUNG BAGHT PULMONARY ARTERY PILNONARY WEIN TRICUSPID VALVE L E F T LUNG S U P. VENA CAVA AORTIC ARCH LEFT PULMONARY ARTERY RIGHT ATRIUM PALMONART PULMONARY ARTERY LEFT ATRIUM PULMONARY VINN PELNONARY WEIN LEFT VENTRICLE RIGHT VENTRICLE B L O O D FLOW THROUGH THE HEART MITRAL VALVE I N 2 MINUTES INF. VENA CAVA Foramina, Canals, etc. Traversed by Various Blood Vessels Vertebral artery- transverse foramina in cervical vertebrae, foramen magnum Internal carotid artery-carotid canal, foramen lacerum, groove for the internal carotid artery Maxillary artery-terminates in pterygoid fossa Posterior superior alveolar artery-posterior superior alveolar foramina Infraorbital artery-inferior orbital fissure, infraorbital groove, infraorbital canal, infraorbital foramen Sphenopalatine artery-sphenopalatine foramen, incisive canal, incisive foramen Descending palatine artery-divides into greater and lesser palatine arteries which traverse same named foramina Inferior alveolar artery-mandibular foramen, mandibular canal Mental artery-mental foramen Mylohyoid artery-mylohyoid groove Ophthalmic artery-optic canal Anterior and posterior ethmoid arteries-anterior and posterior ethmoid foramina Middle menningeal artery-foramen spinosum Internal jugular-jugular foramen EXTERNAL CAROTID ARTERY LINGUAL- → SUPRAHYOID → DORSAL LINGUAL → SUBLINGUAL → DEEP LINGUAL - TONGUE - SOFT PALATE - SUBLINGUAL SALIVARY GLAND - MUSCLES ATTACHED to HYOID ARTERIAL SUPPLY: FACIAL- - MAXILLARY (3 PARTS) → ASCENDING MANDIBULAR PART: PALATINE → INFERIOR ALVEOLAR → TONSILAR - LOWER TEETH - CHEEK → SUBMENTAL - MYLOHYOID → GLANDULAR BRANCHES MUSCULAR PART: → SUPERIOR LABIAL → MASSETERIC → - MASSETER → INFERIOR LABIAL → DEEP TEMPORAL → - TEMPORALIS PTERYGOPALATINE PART: - SOFT PALATE - PALATINE TONSIL - ROOT of TONGUE - SUBMANDIBULAR & SUBLINGUAL SALIVARY GLANDS - LIPS → DESCENDING - HARD PALATE PALATINE - SOFT PALATE → POSTERIOR SUPERIOR ALVEOLAR - PALATINE TONSIL - UPPER PREMOLAR & M O L A R S → INFRAORBITAL → - UPPER TEETH It gives off six branches before it divides into two terminating branches. They are in ascending order: • superior thyroid, • ascending pharyngeal, • lingual, • facial, • occipital, and • posterior auricular. The two terminating branches are the • maxillary and • superficial temporal arteries. Lingual artery supplies the tongue, Floor of the mouth and suprahyoid muscles. FACIAL ARTERY 1) The facial artery runs anteriorly and superiorly near the labial commissure and along the lateral side of the naris of the nose. 2) The facial artery terminates at the medial canthus of the eye. 3) Supplies the face in the oral, buccal, zygomatic, nasal, infraorbital, and orbital regions. o Cervical – Ascending Palatine, submental and tonsillar o Facial branches – Glandular (submandibular), Angular, Superior Labial & Inferior labial *Face, palate, tonsils, submandibular, stylohyoid, digastric muscles Maxillary artery Acessory middle meningeal artery Masseteric artery Middle meningeal artery Deep temporal arteries Pharyngeal artery - Artery of pterygoid canal Sphenopalatine artery Infraorbital artery Anterior superior alveolar artery Deep auricular artery Anterior tympanic artery Inferior alveolar artery Mylohyoid artery Posterior superior alveolar artery Greater palatine artery Lesser palatine arteries Buccal artery Lingual branch Incisive branches Mental artery • 1st Mandibular part • 5 branches → Retromandibular foramen • 2nd Pterygoid part • 5 branches → Infratemporal foramen • 3rd Pterygopalatine part • 6 branches → Pterygopalatine foramen Epicranial Surprise Orbicularis oculi Closing eyelid and squinting Corrugator supercilii Frowning Orbicularis oris Closing and pursing lips as well as pouting and grimacing Buccinator Compresses the cheeks during chewing Risorius Stretching lips Levator labii superiori s Raising upper lip Levator labii superiori s alaeque nasi Raising upper lip and dilating nares with sneer Zygomaticus major Smiling Zygomaticus minor Raising upper lip to assist in smiling Levator anguli oris Smiling Depressor anguli oris Frowning Depressor labii inferi oris Lowering lower lip Mentalis Raising chin protruding lower lip Platysma Raising neck skin and grimacing Class I Malocclusion •The MB cusp of the maxillary first molar occludes with the MB groove of the mandibular first molar. Facial profile as described by many clinicians with the older term mesognathic. Class II Malocclusion Class II malocclusion (distoclusion) MB cusp of the maxillary first molar occluding (by more than the width of a premolar) mesial to the MB groove of the mandibular first molar. • The older term for describing the facial profile in Class II, division I, is retrognathic. Class II Malocclusion Division I Division II • Based on the • Position of the anterior teeth. • Shape of the palate • Resulting facial profile. Class II Malocclusion Division I maxillary incisors protrude facially from the mandibular incisors causing a severe over bite (or deep bite). Upper incisors are tilted outwards, creating significant overjet. Division II Protrusive maxillary incisors, the maxillary central incisors are either upright or retruded. Upper incisors are labially inclined. Class III Malocclusion The MB cusp of the maxillary first molar occludes (by more than the width of a premolar) distal to the MB groove of the mandibular first molar. • The older term that describes the facial profile with a Class III malocclusion is prognathic.

Human Embryology: From Zygote to Organogenesis

Developmental Stages from Zygote to Infancy

The Beginning of Life Life begins at fertilization. Fertilization refers to the meeting of the female sex cell and the male sex cell. These sex cells are developed in the reproductive organs called gonads. The male sex cells called spermatozoa (singular: spermatozoon) are produced in the male gonads called testes. On the other hand, the female sex cells called ova are produced in the female gonads known as ovaries. The fertilized egg cell known as zygote contains all the hereditary potentials from the parents. This zygote goes to the uterus and continues to grow during the gestation period of about 280 days or 36 weeks or 9 calendar months. Each parent contributes one sex chromosome to the offspring. A male parent may pass either an X or a Y chromosome while a female always gives the X chromosome. When an X chromosome comes from the father and meets the X chromosome from the mother, the resulting combination is XX which indicates a female offspring. However, when the father produces a Y chromosome which pairs with the X chromosome from the the mother, the resulting combination is XY, signifying a male offspring.

36. Embryonic development – early stages (zygote to neurula)

Unit 6: Developmental Psychology

Unit 6: Developmental Psychology (copy)

Unit 6: Developmental Psychology (copy)

Unit 6: Developmental Psychology (copy)

Unit 6: Developmental Psychology (copy)

Cleavage: From zygote to blastocyst

Gametes, zygote, meiosis, chromosome number

KEY WORDS AND DEFINITIONS - Penis is The organ in the male reproductive system that carries urine and semen to the outside of the body. Vagina is A muscular tube that leads from the cervix to the outside of a woman's body. Reproductive system are The organs and tissues involved in producing offspring. Testicle is The male reproductive organ the produces sperm in animals Ovary is A pair of organs in the female reproductive system where ova (eggs) and hormones are produced. Ova is The female gametes produced by ovaries in animals (singular: ovum) Sperm is The male sex cell or gamete Foetus is An unborn baby. Usually eight weeks from conception. Gamete is The sex cell of an organism, in humans they are sperm (male) and ovum (female) Uterus is Also known as a womb. This is where the fertilised egg (ovum) develops. Oviduct is Also called a Fallopian tube or egg tube, this tube leads from an ovary to the uterus. Ovulation is The process of releasing an egg from an ovary. Umbilical cord is The cord that connects the foetus to the placenta. It contains blood vessels. Placenta is The organ in the uterus of pregnant mammals that allows the transfer of nutrients and waste products between the mother and the foetus through the umbilical cord. Fertilisation is the joining of the nucleus of two gametes Embryo is An organism in the early stages of development Gestation is The time during which a fertilised egg develops into a baby ready to be born. Amniotic fluid is Liquid that protects the foetus in the uterus. Menstruation is The loss of blood and tissue from the lining of the uterus through the vagina during the menstrual cycle. Implantation is When embryo embeds itself in the uterus wall Zygote Cell is formed when two gametes combine

Unit 6: Developmental Psychology

Unit 6: Developmental Psychology (copy)