Anthropology Exam 2 PDF

What is Process of change in biological physiology or morphology adaptation? Resulting from an altered environment Improves evolutionary fitness (survival and reproduction) Process depends on degree and timing of exposure...

What is Process of change in biological physiology or morphology adaptation? Resulting from an altered environment Improves evolutionary fitness (survival and reproduction) Process depends on degree and timing of exposure 20  Timescales of Adaptation Model Timescale of Input Mode of Adaptation Seconds/Hours Allostasis Days/Months/Seasons Acclimatization Years Developmental Adaptation Decades Genetic Adaptation Centuries Allostasis – The regulation of internal biology through rapid changes in physiology 21  Timescales of Adaptation Model Timescale of Input Mode of Adaptation Seconds/Hours Allostasis Days/Months/Seasons Acclimatization Years Developmental Adaptation Decades Genetic Adaptation Centuries Acclimatization – Physiological changes that occur over the course of days to weeks that work to maintain biological functions in response to a new environmental condition 22  Timescales of Adaptation Model Timescale of Input Mode of Adaptation Seconds/Hours Allostasis Days/Months/Seasons Acclimatization Years Developmental Adaptation Decades Genetic Adaptation Centuries Developmental adaptation – Changes in physiology or morphology that occur during development in response to environmental conditions that result in an improvement in fitness 23  Timescales of Adaptation Model Timescale of Input Mode of Adaptation Seconds/Hours Allostasis Days/Months/Seasons Acclimatization Years Developmental Adaptation Decades Genetic Adaptation Centuries Genetic adaptation – Adaptations to environmental conditions that arise through natural selection and are heritable via the genetic code 24  Human Energy Allocation Model Total Energy Budget Basal Metabolism Dietary thermogenesis Growth & Maturation Thermoregulation Reproduction Immune Activity Physical Activity Maintenance Production Allocation rule: in most organisms, the energy budget is finite, and thus must be allocated across competing biological functions 25 What is metabolic health? A person’s risk of developing cardiovascular disease and/or adult-onset (type II) diabetes mellitus Poor metabolic health is characterized by Hypertension Systolic/diastolic blood pressure > 130/85 mm Hg 26  Metabolic Health and Adipose Tissue Subcutaneous adipose tissue (SAT) Distributed on hips, thighs and buttocks Produces fewer molecules that stimulate inflammation Visceral adipose tissue (VAT) SAT SAT Located closer to important VAT VAT organs Produces more inflammatory molecules 27  Epidemiological Transition The shift from infectious diseases to non-infectious diseases as primary causes of mortality “Pre-transition” Society High death rate due to epidemics, childhood infectious disease Low life expectancy “Post-transition” Society Improved sanitation, public health, and medical technology -> reduced infectious disease rate Chronic, degenerative diseases become primary cause of death Increased life expectancy  Lecture 15: Psychosocial Stress Epidemiological Parasympathetic transition nervous system Homeostasis Neurotransmitter Allostasis Hormone Stressor Acute vs. chronic stress HPA axis Autonomic nervous Cortisol system Sympathetic nervous system  What is stress? Some useful terms Homeostasis The state of steady internal physical and chemical conditions maintained by living systems Allostasis The regulation of internal biology through rapid changes in physiology Different from homeostasis because this concept recognizes that the correct biological “set-point” is context-dependent Stressor Anything in the environment that elicits an allostatic response Characteristics of the acute stress response Rapid mobilization of energy from storage sites (like body fat) Inhibition of future energy storage Blocking the breakdown and digestion of food Increase in breathing rate, blood pressure and heart rate In order to transport nutrients and oxygen at a faster rate Halt energy-expensive processes Growth, reproduction, tissue repair  The Autonomic Nervous System Regulates unconscious bodily functions such as Heart rate, blushing, goosebumps, digestion, etc. Includes two components: Sympathetic nervous system (SNS) Activated by stress Parasympathetic nervous system (PNS) Turned off by stress Sympathetic Nervous System In charge of the “fight or flight” response Produces epinephrine (neurotransmitter)/norepinephrine (hormone) Neurotransmitter A chemical messenger that is produced by nerve cells that travels a short distances and causes a neighboring cell to respond Hormone A chemical messenger produced by a nerve or some other type of cell that is released into the bloodstream and sends a message across the body Hypothalamus -Pituitary- Adrenal (HPA) Axis  Hypothalamus-Pituitary- Adrenal Axis Brain processes psychosocial stress Causes the hypothalamus (within the brain) to produce corticotropin releasing hormone (CRH) CRH travels to the pituitary gland Pituitary gland produces adrenocorticotropic hormone (ACTH, a.k.a. corticotropin) ACTH travels to the adrenal glands The adrenals produce glucocorticoids, such as cortisol Cortisol: a stress hormone and a metabolic hormone Functions to increase blood glucose levels, suppress the immune system, aid in metabolism, and decrease bone formation Has a diurnal rhythm Lecture 16 – UV Adaptations Melanin and its MC1R gene function Folate Melanocyte Vitamin D Pheomelanin Tanning response Eumelanin Ultraviolet radiation (UVR) Risks and benefits of ultraviolet radiation (UVR) exposure Risks Short term – Sunburn Long term – premature aging, skin cancer, eye diseases Degrade folate Folate – vitamin responsible for red blood cell formation and cell growth and function Critical building block (especially during embryonic development) Risks and benefits of ultraviolet radiation (UVR) exposure Risks Benefits Vitamin D production (helps your body absorb calcium and phosphorus to assist in bone growth/maintenan ce) Melanin and its function 3 types – Eumelanin (black and brown variants) - responsible for dark pigmentation of skin, eyes, and hair e.g. black or brown hair = varying amounts of black and brown eumelanin E.g. blond hair = no black eumelanin but some brown eumelanin Pheomelanin- responsible for reddish pigmentation lips and nipples E.g. red hair = equal parts eumelanin and pheomelanin Neuromelanin – pigments your neurons (you never see these colors) Melanin and its function Function – protection from UVR Absorbs rays from UVA, UVB, UVC, and blue light Protects deeper skin cells from damage NOTE: pheomelanin doesn’t protect against UV Many red heads burn easily Tanning response When skin produces eumelanin pigment as a result of seasonal high UVR exposure The outcome of UV-induced stress Regulated by melanocortins Tans produced under natural UVB exposure provide minimal photoprotection Tans produced under UVA-rich sunlamps have no protective benefit Lecture 17: Biological Adaptations to Cold Climates Allen’s Rule Brown adipose tissue Bergmann’s Rule Acclimatization to cold Vasoconstriction/ stress vasodilation Hunting’s response Thermogenesis Developmental Non-shivering adaptations to cold thermogenesis stress Biological Adaptations to Cold Stress Generate Heat Prevent Heat Loss (Thermogenesis) Body Composition Elevated BMR Body Morphology Shivering Vasoconstriction Non-shivering Thermogenesis (NST) Body Proportions and Climate Bergmann’s Rule Larger animals are found in colder environments and smaller animals are found in warmer regions Larger animals are more efficient at maintaining heat They radiate less body heat per kg of body mass Red fox Asian desert red fox  Body Proportions and Climate Allen’s Rule Animals adapted to warm climates will have longer limbs and appendages than animals adapted to cold climates In a hot climate, it is advantageous to have a high surface area-to-volume ratio In a cold climate, it is advantageous to have a low surface-area-to volume ratio  Brown Adipose Tissue (BAT) From Muzik et al. (2013) J Nucl Med 54:525 Brown Adipose White Adipose From Enerback (2010) Cell Metab 11:248-252 Brown Adipose White Adipose Acclimatization to Cold Stress Lower shivering threshold, faster initiation of NST Hunting’s response Process of alternating vasoconstriction and vasodilation Increase in BMR Increase in thyroid hormone production and tissue uptake from circulation Increase in brown adipose tissue (BAT) Lecture 18: Biological Adaptations to Hypoxia Acute and chronic mountain sickness Hypobaric hypoxia Hypoxic ventilatory Candidate genes response Genome-wide Vital capacity association study Residual volume Oxygen transport Hypobaric hypoxia Gas composition of ambient air Oxygen: 21% Nitrogen: 78% Argon, carbon dioxide and other gasses: 1% At high altitude the column of atmosphere that compresses the air is shorter Results in a lower barometric pressure Which results in fewer molecules of oxygen per volume of air  Multiple illnesses related to altitude Know the order of severity Chronic Mountain Sickness Some well-adapted high-altitude residents can lose their adaptation and become ill Symptoms Headache, breathlessness, bone fatigue, insomnia, confusion Risk factors Male, over 50 years old, overweight O2 Transport in Andean and Tibetan Highlanders Tibetans Andeans Elevated blood flow to Elevated blood flow to brain and extremities brain and extremities High lung capacity High lung capacity Due to high VC Due to high RV Due to high RV High hemoglobin Elevated hypoxic concentration ventilatory response (HVR)  Lecture 19: Immune function, Hygiene Hypothesis and Microbiome Immune system Commensal Innate immunity relationship Adaptive immunity Symbiotic Antigen relationship Autoimmune Pathogenic disease relationship Hygiene hypothesis Functions of the gut microbiota Microbiota  The Immune System A host defense system comprising of many biological structures and processes within an organism that protects against infectious disease Made up of two components Innate immunity Adaptive immunity  Innate Immunity Defenses that don’t depend on prior exposure to the disease Evolved before the adaptive immunity system Represent the body’s first line of defense against infection and injury Examples of components of innate immunity Mucosal membranes Antimicrobial soluble proteins in blood, saliva and tears Phagocytic cells that scavenge extracellular molecules Example: Neutraphils (type of white blood cell) Inflammatory response  Adaptive Immunity Also known as acquired or specific immunity Depends on prior exposure to an antigen Defining features Specificity Diversity Memory Examples of components of adaptive immunity T lymphocytes (such as killer T cells) B lymphocytes  Autoimmune Disease A condition arising from an abnormal immune response to a normal part of the body Common examples Celiac disease Diabetes mellitus type 1 Graves’ disease Inflammatory bowel disease Multiple sclerosis Rheumatoid arthritis  Hygiene Hypothesis All living things evolved with a suite of parasites Bacterial and viral infections during early life direct the maturing immune system The lack of infections in industrialized countries due to improved hygiene and use of antibiotics may alter the human immune system such that it responds inappropriately to innocuous substances Riddled with Life: Friendly Worms, Ladybug Sex, and the Parasites that Make Us Who We Are Example of testing the Hygiene Hypothesis: Treating Crohn’s Disease with worms Worms stimulate the Th-2 response, which helps regulate Th-1 activity Malfunctioning Th-1 response is characteristic of Crohn’s disease Pig whipworms (Trichuris suis) Doesn’t harm humans because they prefer a pig host Hypothesis: infect with pig whipworm -> regulate Th-1 activity -> treat Crohn’s disease  Microbiota Ecological communities of commensal, symbiotic, and pathogenic microorganisms found in and on all multicellular organisms Commensal relationship A relationship between two species where one species receives benefits and the other neither benefits nor is harmed Symbiotic relationship Both species benefit from the relationship Pathogenic/Parasitic relationship One species benefits and the other is harmed  Functions of the Gut Microbiota Immune function Continuing cross-talk between the microbiota of the gut and the immune system helps maintain immunological balance Metabolism Helps break down and absorb nutrients, especially certain carbohydrates Communicate with the brain Microbiome-gut-brain axis Biochemical signals from microbiota -> intestine -> brain