Exam 1
Neuron Structure
Synapse
Tiny gap between neurons, signals cross the synapse to communicate and send signals to other neurons
Semipermeable membrane
The neuron's outer surface, allowing for smaller molecules and molecules with no charge to pass through, stopping larger or charged molecules
Soma
Cell body, where the nucleus of the neuron is located, maintains the cell and keeps the neuron functioning efficiently
Dendrites
Branches of the soma, where signals are received from other neurons and transmit electrical signals to the axon
Axon
Major extension of the soma, carries signals away from the soma, includes myelin sheath, nodes of ranvier
Axon terminals
Located at the end of the neuron, responsible for transmitting signals to other neurons. Contain neurotransmitter vesicles (sacs that store neurotransmitters, making them available for when signal transportation is necessary)
Neurotransmitters
The chemical messengers of the nervous system
Myelin sheath
Acts as insulator of the axon and increases speed of the signal transfers
Nodes of Ranvier
Gaps in the myelin sheath, signals can jump across the Ranvier, which further speeds up the transmission process
The Nervous System
Send messages from various parts of your body to your brain, and from your brain to your body for directions. Regulate your thoughts, memory, learning, feelings, movements, senses, healing, sleep, heartbeat and breathing patterns, response to stressful situations, digestion, body processes, etc.
Central nervous system
Comprises of the brain and spinal cord, read signals from nerves to regulate how you think, move, and feel
Peripheral nervous system
Contains sensory and motor nerve cells, relays information from your brain and spinal cord to your organs, arms, legs, fingers, toes, etc. Composed of your somatic nervous system and autonomic nervous system.
Somatic nervous system
Focuses on the voluntary movement of the body. Delivers information from your senses to your brain, also carries commands from brain to muscles, works mainly with sensory input and movement control.
Autonomic nervous system
Regulate activities you do without thinking about them, involved mostly with your internal organs. Composed of the sympathetic nervous system, the parasympathetic nervous system, and the enteric nervous system.
Sympathetic nervous system
Activates body processes that help you in times of stress or danger, including fight-or-flight response. Increases heart rate and breathing, dilates pupils, inhibits digestion, more sweating, shuts down parasympathetic responses in order to utilize more energy in the fight-or-flight response.
Parasympathetic nervous system
Responsible for the rest-and-digest body processes, works to maintain long-term health and a healthy balance across all the body's functions. Slows your heart rate, dilates blood vessels, enhances digestion, more relaxed muscles, etc.
Enteric nervous system
A network of nerve cells in the digestive system that controls digestion and other functions, the largest and most complex unit of the peripheral nervous system
Organelles/Cellular Structure
Endoplasmic Reticulum
Produces proteins and lipids for the rest of the cell to function on. Contains the rough endoplasmic reticulum and the smooth endoplasmic reticulum. "Scaffolding for ribosomes".
Rough endoplasmic reticulum
Covered in ribosomes, which creates the rough appearance, which produce proteins.
Smooth endoplasmic reticulum
Produces and stores lipids and hormones.
Mitochondria
Known as the powerhouse of the cell, it produces energy (ATP). Properly maintained energy levels provide necessary energy for learning, memory, brain health, etc.
Golgi Apparatus
Processes and packages proteins and lipids for transport within and outside the cell. Used to modify and direct neurotransmitters to the right locations. Collecting and packaging center for export out of the cell.
Nucleus
Contains the cell's genetic material and controls cell functions. Synthesis of neurotransmitters as well. Can cause things like Huntington's disease, which affects motor control, mood regulation, and cognition due to abnormalities in the nucleus.
Lysosomes
Break down waste and cellular debris. Dysfunction is related to Alzheimer's and Parkinson's. Degrades debris and contains hydrolytic enzymes (enzymes that help break down complex molecules).
Vesicles
Found in neurons, store neurotransmitters and release them into the synapse during neural communication. Focused on transport.
Vacuoles
Help with the removal of waste products and store neurotransmitters, waste products, ions, etc. Focused on storage.
Cellular Membrane
Essential to neural communication given their electrical charge, they also house receptors that bind to neurotransmitters, which play a central role in mood regulation, learning, and memory. A lipid bilayer, semi permeable, hydrophobic.
Ribosomes
Form proteins, are typically associated with rough endoplasmic reticulum, but also freely float throughout the cytoplasm
Cytoplasm
Jelly-like substance inside a cell, provides a medium for chemical reactions and supports the movement of materials inside the cell such as ribosomes.
Cytoskeleton
A network of protein fibers and filaments inside a cell that provides structural support, helps maintain the cell's shape, and facilitates movement.
Microtubules
One of the main components of the cytoskeleton. Long, hollow tubes that provide structural support. Helps make up the cytoskeleton, particularly of the structure of axons.
Basic Principles
Health care, education, etc. are only as strong as their weakest link.
Early life exposures matter, good or bad.
The nervous system changes rapidly during early life
Infancy and childhood are a time of great sensitivity to environmental factors
Peanut allergies have increased 55% in the last five years in the USA, because parents were told not to expose their children to it, which then didn't build up the children's immune system to it
Exposure to peanuts in early childhood decreases the likelihood of developing an allergy for it
Doctors were once advised against breastfeeding, but breast milk actually contains large amounts of antibodies and other essential nutrients for the baby
The FDA also found lots of dangerous things such as BPA's in baby bottles, which can be very harmful to a baby
Fetal alcohol syndrome develops as the baby is exposed to alcohol while in the womb, most susceptible during the first and second trimester of a woman's pregnancy
Perfect pitch is also developed in early childhood
Perfect pitch - the ability of a person to identify or re-create a given musical note without the benefit of a reference tone
Cat litter is dangerous for pregnant women because there are things such as teratogens, which can cause birth defects among other things, in embryos/fetuses
Thalidomide was once a nausea treatment for pregnant women, but it was discovered that it actually creates strong birth defects in children
Zika virus causes microcephaly and other birth defects
Microcephaly - a birth defect where a baby's head is smaller than expected
Most disease, particularly chronic disease, is an exacerbation of normal changes. In other words, disease is not a threshold event but rather a continuum change.
High prevalence of coronary atherosclerosis in asymptomatic teenagers and young adults
Coronary atherosclerosis - A condition caused by the buildup of fats, cholesterol and other substances in and on the walls of the heart arteries
This is why biomarkers are so valuable to science and medicine
Biomarkers - Measurable characteristics that can indicate a person's health or risk of disease
E.g: OCT machine, Actigraphy, Coronary calcium score, blood pressure and heart rate
Optical coherence tomography (OCT) - a non-invasive imaging test that uses light waves to take cross-section pictures of your retina, tests for macular degeneration, glaucoma, etc.
Macular degeneration - an eye disease that can cause blurred or lost central vision, can be tested for by an OCT machine
Glaucoma - a group of eye diseases that can damage the optic nerve and lead to vision loss or blindness, can be tested for by an OCT machine
Actigraphy - a non-invasive method that measures a person's activity and rest cycles over a period of time, can detect sleep disorder of patterns in your sleep-wake cycle that affect your health
Coronary calcium score - a measurement of calcium in the coronary arteries, which can help indicate the risk of health disease
Nearly all biological traits can be described as a normal curve.
E.g: IQ scores, human skin color distribution, susceptibility of disease
CoV - coefficient of variation - measures relative event dispersion, commonly used in comparing relative risk
Most age-related decline is heterogeneous, and can be described as a heteroscedastic function.
Heterogeneous - Derived from another source or species
Heteroscedastic - A statistical term that describes when the variance of errors (when there is variability of scores caused by factors other than the IV) is not constant across observations
Diastolic blood pressure - the pressure in your arteries when your heart relaxes and fills with blood between heartbeats - increases with age
Some older people retain young levels others show increase
Homoscedasticity - a statistic assumption of equal or similar variance in different groups being compared
Some variables do not spread with age, such as presbyopia
Presbyopia - Loss of your eyes' ability to focus on nearby objects
Bodily systems are not autonomous.
The gut-brain axis - Consists of bidirectional communication between the central and the enteric nervous system, linking emotional and cognitive centers of the brain with peripheral intestinal functions
IBS is an example of the disruption of this relationship
Psychoneuroimmunology - A term used to describe the interactions between the emotional state, nervous system function, and the immune system
E.g: function of the nervous system, as you go into stress and your body activates the sympathetic nervous system, digestion and all the functions of the parasympathetic nervous system turn off, which work towards long-term health. So, if your body is in stress too much, your sympathetic nervous system is always activated and you lack the benefits of the parasympathetic nervous system, which can in term affect the immune system function
Drug side effects - one chemical can affect many things
Iatrogenesis - any harm or illness caused unintentionally by medical treatment or diagnostic procedures
E.g: Adverse drug reaction (ADR) - any noxious, unintended, and undesired effect of a drug, which occurs at doses used in humans for prophylaxis, diagnosis, or therapy
Prophylaxis - Preventative care, action taken to prevent disease, especially by specified means or against a specified disease
Prospective study - Develop and conduct studies on subjects before they develop outcomes, follow a group of people over time, looking at the future
Retrospective study - Look back at data collected from previous studies/patients to investigate outcomes that have already occurred, looking at the past
Sensory input affects cognitive output
Taking care of your hearing and vision slows cognitive decline by 50-75%
Biology is plastic (mutable).
The brain is adaptable, we have more receptors in our brain than are necessary, so when we lose some due to things like strokes, our brain can adapt and use the ones we still have to carry out functions
Parkinson's disease and intensive exercise therapy - people with PD can undergo intensive exercise therapy and relearn how to do things that their brain lost the ability to, such as certain motor functions. This is because the brain is adaptable
Learning new things and new skills is a great way to prevent brain function loss
Short-term piano training influences verbal memory, executive functioning, and pre-attentive processing of sounds in older adults for the better
Use it or lose it…
If you want to retain balance, you must practice balance, if you want to retain a range of motion, you must regularly assume a range of motions, etc.
An older adults falls every second of every day
One in four older adults reported a fall in 2014
Falls are the #1 cause of hip fractures
Many systems in the body are bicameral.
E.g: parasympathetic nervous system and sympathetic nervous system balance each other out and are dependent on each other (the enteric nervous system can work independently of the two)
The body is at homeostasis when the sympathetic and parasympathetic nervous systems' balance each other out, but small stressors keep the sympathetic system active, minimizing parasympathetic (maintenance, repair, etc. ) activation
Homeostasis
Unhealthy nervous system activation progression
Opponent processing of color
Perception of color is controlled by three opposing pairs of vs. green, blue vs. yellow, black vs, white
The activation of one inhibits the perception of the other
E.g: If you look at something blue, the blue channel is activated, while the yellow channel is suppressed
So, you cannot see a bluish-yellow
Also explains afterimages - If you stare at a yellow object for a long time and then look away, you might see a blue afterimage because the yellow channel gets fatigued, allowing the blue channel to briefly dominate
You can have a slightly dominate color, which explains why you might see certain colors in images such as this dress
Modern life is often inconsistent with our evolved biology
Human biology evolved over hundreds of thousands of years
E.g: The "thrifty gene" hypothesis
There is a certain group of Indigenous Americans, The Pimas, who historically lived in the deserts of the Arizona area and developed the ability to survive on the "desert diet" which mostly consisted of plants and lived a very active lifestyle. As civilization evolved and diets changed, this group lives with the highest prevalence of diabetes, due to this gene evolution (their body is wired to live off the "desert diet", not the modern diet)
The pandemic of myopia (nearsightedness), "new" and mostly due to modern lifestyles
"Keep myopia away, go outdoors and play"
Endemic - A disease regularly found in a certain area or population
E.g: malaria in certain tropical regions due to its consistent presence year-round
Epidemic - Sudden increase in cases in a particular area or population
E.g: Sudden increase in flu in one city during the winter
Pandemic - Global outbreak of a disease across multiple regions or continents (epidemic spread)
E.g: COVID when it spread across the world
Emmetropization - eye lengthens according to growth signals (near a device for example, or far, like in the real world)
Presbycusis (also "new") - Loss of high frequency hearing with age
This did not exist before, because we did not have the stark loud noises before, such as alarms, headphones, etc.
Cancer is largely a disease of the Western lifestyle
Older skeletons do not show similar joint degradation despite massive "wear and tear"
Modern food products differ from the single ingredient foods that our bodies had evolved to digest
Modern thinking is also incompatible with our evolutionary biology
Mobile telephone use is associated with changes in cognitive function in young adolescents
Much of the human brain is dedicated to vision and movement, making encoding visual-motor improves retention
Frontal lobe - responsible for thinking, movement, memory, etc. also controls personality and emotions
Parietal lobe - Helps interpret sensory information, also helps with attention, language, and visuospatial processing
Temporal lobe - Helps process information from the senses
Occipital lobe - processes images from the eyes and connects them to stored images in memory, allowing for image recognition
Human biology (including susceptibility to disease) evolved.
Mechanisms of natural selection
Pesticides and herbicide encourage the evolution of pest/herbicidal resistance
Antibodies promote evolution of more resistant microorganisms
Percentage of salmonella-poisoning cases studied in which bacteria were resistant to five commonly used antibiotics
Sickle cell anemia evolved as a defense against malaria
Sickle cell anemia - A blood disorder that affects the shape and function of red blood cells
The sickle cells kill the malaria parasite
Hemochromatosis evolved as a defense against the bubonic plague
Hemochromatosis - An inherited metabolic disorder causing iron overload in tissues
Treated by phlebotomy - removal of blood from a vein
Works as a treatment by regularly removing blood from the body
People with hemochromatosis should avoid eating iron in their diet, such as spinach, red meat, etc.
Dominant disease in people of European descent
Types 1, 2, and 3 are autosomal recessive while type 4 is autosomal dominant
Autosomal recessive - you need to have two faulty genes in order to actually have the disease, not simply be a carrier
Autosomal dominant - you only need one faulty gene to actually have the disease
Paradoxically causes macrophages to be starved for iron
Macrophages - a type of white blood cell that surrounds and kills microorganisms, removes dead cells, and stimulates the action of other immune system cells
Iron in the blood lowered risk of the plague
Autosomal Dominant Compelling Helio Ophthalmic Outburst Syndrome (ACHOO syndrome) - Sneezing when going from dark to bright environments
Evolved as protection from fungi, etc., in caves
Cerumen - ear wax, protects the ear canal and is produced by glands in the skin
Evolved to repel insects
Most diseases can be described by a diathesis-stress model.
Diathesis - predisposition
Dis-ease results when insult exceeds protection, a combination of a person's predisposition and their exposure to stressor
E.g: skin cancer
Most diseases in developed countries are acquired and have a significant life-style component.
Our genes have not changed but our life expectancy has doubled
The frequency of most diseases increases with age (time for lifestyle to matter)
Whack-a-mole medicine
Degenerative disease tends to cluster
The age pyramid is inverting in many countries, there are more older people than younger people
SES (Socioeconomic Status) is one of the most significant predictors of health/disease
Aging is different across SES
In a study taking a train from one side of a city to another, and as you went from the rich to the poor side of the city, every other train stop represented a lost year of life expectancy
Whitehall studies
The poorest half of the world own less than 1% of the worlds wealth
Disease risk vs SES is not necessarily driven by the access to health care, but by education
Some exceptions to the rule: hospitalism, multiple sclerosis, skin cancer, endometriosis
Hospitalism - the adverse effects of a prolonged stay in hospital, such as the slowing of development in children
Common in the 30s, infants did poorly in hospitals and kept in incubators due to fear of harmful germs. But, infants actually benefit from touch, and this was deprived of them during this time
Premature infants are often kept in oxygenated incubators to carefully monitor oxygen levels once they are out of the constant levels of the mother's womb (an example of how iatrogenic effects can be hard to avoid)
Multiple sclerosis (MS) - a chronic disease where antibodies break down the myelin sheaths in the brain and spinal cord, which affects the central nervous system
Epidemiology - branch of science that studies the distribution/determinants of disease in specific populations
Prevalence vs. incidence
Prevalence - the total number of a population that has a specific characteristic at a given time
Incidence - The number of new cases of a characteristic that develop in a population over a specified time period
E.g. of incidence and prevalence: There is a measurement of diabetes cases in a year. 15% of the population has diabetes for over a year and 5% got diabetes that year. Prevalence - 20% and Incidence - 5%
Endometriosis - When uterine tissue grows outside the uterus and causes painful periods and bleeding
Sticky endometrial cells within uterine cavity
More common in lean women, and it is more common to be lean as you are richer
Skin cancer - superficial spreading melanoma
Likely more common because they vacation to more places where they would develop sunburns, tanning beds, increased awareness and access to care
So, higher likelihood of skin cancers in richer populations not necessarily because they solely are more likely to get it but they are more likely to go to the doctor and get treatment for it
Also higher likelihood of treatment in populations with lighter skin tones, which has impacts on SES
All of these are more prevalent in richer populations
Poverty did not always translate to increased risk
Treatment is not always the answer. (Addiction)
Treatments sometimes yield little actual benefit, are risky, or cause as many problems as they solve
Morbidity rate- the rate at which a disease or illness occurs in a population
Mortality rate - the number of deaths in a population
Alcohol use in the US
35% abstain
65% moderate drinkers (including binging)
6-10% heavy drinkers
10% addiction rate
Light alcohol use: French paradox, buffers stress, improves LDL/HDL ratio, interferes with fat absorption, antioxidants, etc.
Binge drinking: 4th leading cause of death due to automotive accidents, 67% deaths due to homicide
Alcohol acts as a central nervous system depressant, which causes disinhibition
Disinhibition - the inability to control one's behavior or to suppress unwanted or inappropriate actions
Alcohol affects the Vestibular system (balance, equilibrium, spatial orientation)
Nystagmus (involuntary eye movements)
A condition that causes involuntary, rhythmic eye movements that can be rapid or slow
Reflexive eye movement in which the eyes track a moving object and then snap back
Field sobriety testing
Putatively, 92% accuracy
Vestibular tests
Baranay Chair Test
Measure nystagmus or performance on tasks
Balance tests (stand on one foot with your eyes closed)
Alcohol effects
Alcohol use disorder (16.3 million)
Alcoholic gastritis ulceration and hemorrhaging
Korsakoff's disease
Due to brain damage caused by Vitamin B1 deficiency
Causes severe anterograde amnesia
Anterograde amnesia - Amnesia when you can't form new memories
Liver cirrhosis
Growth of connective tissue destroys liver cells, liver is scarred and permanently damaged
Pancreatic undigested food in stools, ascites, abdominal pain
Digestive cancers
Cardiovascular problems
Fetal alcohol syndrome (1%)
A group of conditions that can occur in a person whose mother drank alcohol during pregnancy
most susceptible during the first and second trimester of a woman's pregnancy
Addiction rates
10% alcohol
70% smoking tobacco
Smoking prevalence (16%)
Falling prevalence, rising numbers
Since 1990, the prevalence of smoking has decreased steadily around the globe. However, as populations have grown, the total number of smokers have increased
There is the presence of classic conditioning in advertisements to get people to start smoking
Usage of celebrities (especially those who are known to be healthy) to get people to associate smoking with being attractive and cool
Would also use advertisements of doctors promoting smoking
Subliminal advertising towards Eros or sex
Attract the sex appeal to attract people to your product
Focus on vulnerable/susceptible groups (young)
E.g: the camel logo appealed towards children, handing out candy cigarettes to children who were too young to smoke, camel cash (contained toys in the catalog)
Camel was once perceived as the "old man's cigarette" but once advertising started, sales to the under 17 year age group went up by a factor of 80
This method is common, e.g. mcdonalds, vaping, etc.
Vaping is technically healthier than smoking cigarettes
If you want something to be true, or don't want it to be true, take that as a red herring
Wanting something is antithetical to the actual truth, this is why the scientific method has many mechanisms for minimizing bias
Mucociliary escalator: The self-clearing mechanism in the lungs that removes particles and pathogens from the airways, lining of the trachea and bronchi
The tar in cigarettes especially defeats this mechanism and leads to things like lung cancer
How to get people to stop smoking?
People have tried putting the physical consequences of smoking on packages, but this doesn't work because when people are addicted, they are not worried about their own health
Addiction is mediated by neural internal reward mechanisms ("because I enjoy it")
Many substances/behaviors are addictive because they activate brain reward areas (reward circuit - dopamine)
Medial forebrain bundle - area of the brain that mediates "reward" and is often stimulated by addiction (prefrontal cortex, nucleus accumbens, ventral tegmental area)
Intracranial self-stimulation was used to identify brain reward areas
Brains were injected into their medial forebrain bundle and they were given the choice to stimulate it. They would chose this over things like food and water, and would pretty much choose pleasure to death
Brain "reward systems" are depressed in subjects with depression
There are also individual differences in addiction that reflect different diathesis (susceptibility)
Reward/pain relief is mediated by internal opiates (endorphins) and are closely associated, it is common to experience a pleasure that is closely related to pain, such as runner's high
Periaqueductal gray matter (PAG) - a brain region that plays a critical role in the modulation of pain
Opioid Epidemic: Addiction Statistics
Almost 50K people die every year from opioid overdose
Over 10 million people misuse opioids in a year
Opioids are a factor in at least 7 out of every 10 overdose deaths
Opioids
"Opioids" was originally used to refer to synthetic opiates only (drugs created to emulate opium). Now the term opioid is used for the entire family of opiates including natural, synthetic, and semi-synthetic
Ex: oxycontin, vicodin, morphine, methadone, fentanyl, etc.
The crisis started with the legitimate need to deal with chronic pain
"More Americans are sick, in other words, than are healthy"
Strategies of companies: target youth, use HPs and celebrities, go overseas (less regulation)
Using health-care professionals
The more opioids doctors prescribe, the more they get paid
There used to be things such as "pill mills", where people could go for pain symptoms and doctors would loosely prescribe opioids
Go overseas
Oxycontin sales began to fall in the US, so companies refocused on their global business, particularly in the developing world
Methods to help:
Methods to get health professionals to stop prescribing: Use triplicate prescriptions
There had to be three copies of each prescription, one to give to pharmacy, one for patient, one for the HP to keep - held them accountable
"Oxycontin distribution was about 50% lower in triplicate states"
Naloxone (Narcan)
Overdose medication reduces deaths
Increase availability of narcan to most places people would need it, such as department stores, etc.
Cellular basis of aging and disease
Basic properties of cells explain much of health/illness
Nervous system
Vascularized, sensitive to hypoxia
Hypoxia - Occurs when oxygen is insufficient at the tissue level to maintain adequate homeostasis
Metabolism, sensitive to metabolic issues
Nutritionally responsive
Neurons have all the same organelles but do not undergo mitosis (mostly), neural disorders are hard to treat
The axon can regrow is the soma is kept viable - this is the idea of neural regeneration
E.g: Post-polio syndrome and collateral sprouting
Post-polio syndrome - A disorder of the nerves and muscles that happens to some people many years after they have had polio. Causes new muscle weakness due to weaker regenerated neurons
Collateral sprouting - The growth of intact axons into neighboring denervated territory
Wallerian degeneration - The process where the distal part of a damaged axon degeneration after injury (apart of neural regeneration)
Acute inflammation is mostly useful and can be used in regeneration, but chronic inflammation is a major promoter of chronic disease
You can even sometimes do things like face transplants and reattaching limbs, if with enough time, because of neural regeneration
Semi-permeable plasma membrane - receptors regulate the entry of materials into the cell
Regulation - the number of receptors increases or decreases depending on the concentration of the extracellular target
To compensate for decreased levels of a neurotransmitter like serotonin, the brain increases the number of receptors for that specific neurotransmitter
Upregulation - The process by which a cell increases its response to a substance or signal from outside the cell to carry out a specific function
Denervation supersensitivity - The growth of (upregulation) of membrane receptors in response to a deficiency
Miosis - Age-related shrinkage of the pupil, can be an indicator of early onset Alzheimer's
Can be tested by pupil dilation test
Diabetes
Insulin regulates entry of glucose
The pancreas produces insulin
Type I Diabetes - lack of insulin-producing cells (Islet cells) which exist in the pancreas
Excess sugar intake causes down regulation of insulin receptors on cell membrane
Type II diabetes - lack of membrane receptors for insulin
Often due to neovascularization
Neovascularization - The process of new blood vessels forming in the body, which can occur in the eye or elsewhere
Most common type of neovascularization - angiogenesis
Angiogenesis - outgrowth of blood vessels from existing ones
Increase in intake of refined sugar is one obvious driving factor of the increase in diabetes
Sugar is added to many seemingly healthy food items
Candy "seconds" sold to farmers to fatten livestock
How cells die (external stress vs internal programming)
Necrosis vs. Apoptosis
Necrosis - the death of body tissue or cells due to environmental factors, such as trauma, infection, oxidative stress, etc.
Apoptosis - Programmed cell death that is triggered by internal signals, such as DNA damage, development, etc.
Humans may have already reached their maximum lifespan
The lifespan in the absence of environmental insult is 126 years
Human maximum lifespan (126) has not changed (average has changed, driven largely by changes in infant mortality)
Scientists may have discovered a way to slow aging by direct reprogramming of human cells
Hayflick number (limit) - the number of times a cell can divide (mitosis) before it dies (apoptosis)
Genetically determined
Often is disrupted by necrosis (environmental stressors)
Telomeres - chromosomal "end caps" that shorten with each cell division
Review: 22 pairs of autosomal chromosomes, 1 pair (2) sex chromosomes
Measuring telomere length is an important new tool for studying chronic disease and health
Most have the genetic program to live to around 80 years, less or more is largely due to behavioral/environmental factors (necrosis)
People with Hutchinson-Gilford Progeria Syndrome have shorter than average telomeres, which causes them to age faster than the average person
Free radical stress (oxidative stress) - When unstable molecules called free radicals build up in the body, which can damage cells, proteins, and DNA
Oxygen is easily converted to radical forms due to its chemical structure. Oxygen naturally has two unpaired electrons in its outer shell, which makes it prone to react with other molecules and form reactive oxygen species (ROS) (type of free radicals)
Acute effects of excess oxidative stress - retinopathy of prematurity
Retinopathy of prematurity - Retinal disease affecting premature babies
Early in evolution of life, plants used oxygen as a competitive tool (kill other plants), who then developed antioxidants to protect themselves
Subsequent species piggybacked on this defense
Antioxidants are electron rich, can quench radical reactions by donating electrons and preventing the buildup of these free radicals, therefore preventing necrosis
This is one of the reasons why plant-based diets can prevent chronic disease, because they provide such antioxidants to help prevent necrosis in all parts of our bodies
Chronic inflammation (inflammaging) is the other major driver of chronic disease
So, the top two drivers of chronic disease is oxidative stress and inflammaging
Miscellaneous:
Microglia - Immune cells that live in the central nervous system and protect the brain and spinal cord from pathogens and damage
Major histocompatibility complex (MHC) - A group of genes that encode proteins that play a vital role in the immune system
Idiopathic - A disease of an unknown cause
Etiology - The study of the causes of diseases
Sarcopenia - age-related loss of muscle, inevitable
To add:
Percentage of obese americans
Most common causes of mortality
Research methods
Relevant readings
Questions:
Homoscedasticity vs heteroscedasticity
Wouldn't presbyopia be heteroscedastic because it is a gradual loss and increases with age? There is contradiction in what I'm seeing online
What was the mnemonic device for Sarah, stare-uh?
How much impact does the lobes of the brain have on the exam?
How do antibodies promote evolution of more resistant microorganisms?
Is it important for us to know which forms of hemochromatosis are autosomal recessive vs dominant?
How does hemochromatosis starve the macrophages of iron?
What do you mean by whack-a-mole medicine?
Can you elaborate on the Whitehall studies?
Can you elaborate more on your definition of endometriosis?
Can you further explain how alcohol affects the VOR?