Untitled Quiz

Lecture 20: Exam 2 Review

• Innate immune system question on exam
• Options for innate immune system component: T Lymphocytes, B Lymphocytes, Mucosal Membrane, Antigens
• Correct answer: Mucosal Membrane

Lecture 12: Historical Perspectives on Human Variation and Race

• Immanuel Kant
• Ethnocentrism
• Scientific racism
• Polygenism vs. Monogenism
• Typology
• Eugenics
• Anthropometry
• Franz Boas
• Plasticity
• Cline
• Tuskegee Study of Untreated Syphilis

European Colonialism and Documenting Human Variation

• European explorers documented and described people and environments since the 1600s
• Ethnocentrism is the tendency to view one's own culture as best and judge others by one's own standards

Early Writings on Race - Immanuel Kant (1724-1804)

• Known for his contributions to philosophy
• During his lifetime, he categorized humanity by skin color and hair texture
• Believed these categories corresponded to behavioral and physical traits
• Believed the aesthetics and other traits of white people were superior

Polygenism vs. Monogenism

• Polygenism: Doctrine that human races were separate biological species descended from different "Adams"
• Monogenism: Doctrine that human races shared a single origin

Typology, Science, and Racism

• Typology is a method to reduce variation to smaller categories based on "ideal" types.
• Anthropometrics are measurements of the human body, head, and face used to distinguish racial groups.
• Problem with anthropometrics: influenced by environment and independently inherited. Clinal distribution pattern.
• Eugenics: Movement that tried to improve the human species via planned breeding

Lecture 13: Contemporary Perspectives of Human Variation

• Genetic determinism
• Racial inequalities in health
• Racial-Genetic determinism
• 3 critiques of racial-genetic determinism
• Embodiment
• Morbidity
• Mortality

What We Know Today

• Races cannot be defined based on gene incidence
• Greater genetic diversity within groups than between geographical divisions
• Race is socially constructed, not biologically determined

First, a Few Key Definitions – Race

• A recent idea created by Western Europeans to account for human differences
• Used to justify colonization, conquest, enslavement and social hierarchy.
• Associated with perceived biological markers

First, a Few Key Definitions – Ethnicity

• Similar to race, it groups people based on common origins/backgrounds
• Usually refers to social, cultural, religious, linguistic and other affiliations.

Explaining Human Genetic Diversity

• Most human genetic diversity evolved in Africa
• Genetic diversity outside Africa is a subset of what exists within Africa due to founder effect and genetic drift

3 Main Critiques of Race as a Genetically Determined Category

• Human genetic variation is clinal
• Most human genetic variation is discordant (traits are independently inherited and don't predict other biological aspects)
• Human genetic variation is widely shared.

What about Genetic Ancestry Tests?

• Perpetuate the idea that genes alone define who we are.
• Genetic determinism: belief that genetic contributions are more important than other factors such as epigenetic and environmental ones

Race and the Embodiment of Social Inequality

• Embodiment (Krieger 2005): Concept of how our social world influences our biology from conception to death

Lecture 14: Human Energetics

• Social Determinants of Health Model
• Intergenerational Inheritance of Health Model
• Adaptation
• Timescales of Adaptation Model
• Homeostasis
• Allostasis
• Acclimatization
• Developmental adaptation
• Genetic adaptation
• Human Energy Allocation Model
• Metabolic health
• Adipose tissue: Subcutaneous and visceral
• Food security

Figure 1: Social Determinants of Health

• Diagram showing factors influencing health outcomes, including economic stability, neighborhood environment, education, food, community and social context, and health care systems

Intergenerational Inheritance of Health Model

• Model influenced by Developmental Origins of Health and Disease (DOHaD)
• Prenatal and infant exposures to environmental conditions can influence disease risk in adulthood

The International Biological Program and the Human Adaptability Project

• Large-scale, international collaboration studying human adaptability and ecological interactions.

What is biological adaptation?

• Process of change in physiology or morphology resulting from an altered environment.
• Improves evolutionary fitness (survival and reproduction).
• Depends on the degree and timing of exposure

Timescales of Adaptation Model

• Allostasis = rapid changes in physiology to regulate internal biology.
• Acclimatization = physiological changes occurring over days to weeks responding to a new environmental condition.
• Developmental adaptation = changes in development responding to environmental conditions that improve fitness.
• Genetic Adaptation = Adaptations to environmental conditions arising through natural selection and are heritable.

Human Energy Allocation Model

• Total energy budget is finite and allocated across competing biological functions (basal metabolism, growth and reproduction, maintenance)

What is Metabolic Health?

• Risk of developing cardiovascular disease or type II diabetes
• Poor metabolic health is characterized by hypertension (systolic/diastolic blood pressure)

Metabolic Health and Adipose Tissue

• Subcutaneous adipose tissue (SAT) is distributed on hips, thighs and buttocks; produces fewer inflammatory molecules.
• Visceral adipose tissue (VAT) is closer to organs; produces more inflammatory molecules.

Epidemiological Transition

• Shift from infectious diseases to non-infectious diseases as primary causes of mortality.
• Pre-transition society: high death rate from epidemics and childhood infectious diseases. Low life expectancy.
• Post-transition Society: improved sanitation, public health, and medical technology reduce infectious disease rates, allowing chronic diseases to become primary cause of death. Increased life expectancy

Lecture 15: Psychosocial Stress

• Epidemiological transition
• Homeostasis
• Allostasis
• Stressor
• Acute vs chronic stress
• Autonomic nervous system
• Sympathetic nervous system
• Parasympathetic nervous system
• Neurotransmitter
• Hormone
• HPA axis
• Cortisol

What is stress?

• Homeostasis: Steady internal physical/chemical conditions maintained by living systems.
• Allostasis: Regulation of internal biology through rapid physiological changes; recognizes that the optimal set-point is context dependent.
• Stressor: Any environmental trigger that leads to the allostatic response.

Characteristics of the Acute Stress Response

• Rapid mobilization of energy (body fat).
• Inhibition of future energy storage and food digestion.
• Increased breathing rate, blood pressure and heart rate to improve nutrient and oxygen transport.
• Halt energy-expensive processes (growth, reproduction, tissue repair).

The Autonomic Nervous System

• Regulates unconscious bodily functions like heart rate, blushing, goosebumps, digestion, etc.
• Sympathetic Nervous System (SNS): activated by stress.
• Parasympathetic Nervous System (PNS): turned off by stress.

Sympathetic Nervous System

• Controls “fight or flight” response.
• Produces the hormones epinephrine/norepinephrine.
• Releases neurotransmitters over short distances.

Hypothalamus-Pituitary-Adrenal (HPA) Axis

• Brain processes psychosocial stress, causes the release of CRH.
• CRH travels to the pituitary gland.
• Pituitary gland releases ACTH.
• ACTH travels to the adrenal glands.
• Adrenal glands produce glucocorticoids (like cortisol), which have metabolic effects.

Cortisol: a stress hormone and a metabolic hormone

• Increased blood glucose levels, suppresses the immune system, affects metabolism, decrease bone formation.
• Has a diurnal rhythm (pattern of levels over the day or night).

Lecture 16: UV Adaptations

• Melanin and its function
• Melanocyte
• Pheomelanin
• Eumelanin
• Ultraviolet radiation (UVR)
• MC1R gene
• Folate
• Vitamin D
• Tanning response

Risks and Benefits of UVR Exposure

• Risks: Sunburn, premature aging, skin cancer, eye diseases
• Benefits: Vitamin D production
• Vitamin D helps absorb calcium and phosphorus for bone growth/maintenance

Melanin and Its Function

• Melanin: 3 types- eumelanin (black/brown), pheomelanin (reddish), neuromelanin (in neurons).
• Function: UV protection by absorbing UVA, UVB, UVC and blue light, protecting deeper skin cells from damage.

Tanning Response

• Skin produces eumelanin due to seasonal high UVR exposure.
• Outcome of UV-induced stress.
• Regulated by melanocortins.
• Minimal photoprotection from natural UVB tans.
• UVA tans offer no protective benefit.

Lecture 17: Biological Adaptations to Cold Climates

• Allen's rule
• Bergmann's rule
• Vasoconstriction/vasodilation
• Thermogenesis
• Non-shivering thermogenesis
• Brown adipose tissue
• Acclimatization to cold stress
• Hunting's response
• Developmental adaptations to cold stress

Biological Adaptations to Cold Stress

• Preventing heat loss: Body composition, Body Morphology, Vasoconstriction
• Generating heat (Thermogenesis): Elevated BMR, Shivering, Non-shivering Thermogenesis (NST)

Body Proportions and Climate - Bergmann's Rule

• Larger animals are adapted to colder climates due to increased efficiency in heat retention.
• Smaller animals are adapted to warmer climates for better heat dissipation.

Body Proportions and Climate - Allen's Rule

• Animals in warm climates have longer limbs to increase heat loss compared to animals in cold environments with reduced limb length.

Brown Adipose Tissue (BAT)

• Specialized tissue generating heat, involved in cold acclimatization in humans and some mammals.

Acclimatization to Cold Stress

• Reduced shivering threshold, faster initiation of non-shivering thermogenesis.
• Alternating vasoconstriction and vasodilation.
• Increased basal metabolic rate (BMR).
• Increase in thyroid hormone production.
• Increased tissue uptake from circulation.
• Increase in brown adipose tissue (BAT).

Lecture 18: Biological Adaptations to Hypoxia

• Acute and chronic mountain sickness
• Hypobaric hypoxia
• Candidate genes
• Genome-wide association study
• Oxygen transport
• Hypoxic ventilatory response
• Vital capacity
• Residual volume

Hypobaric Hypoxia

• Reduced atmospheric pressure at high altitudes leads to lower oxygen concentrations in air.

Multiple Illnesses Related to Altitude

• Various illnesses at different altitudes: AMS, HACE, HAPE
• Order of severity: AMS, HACE, HAPE

Chronic Mountain Sickness

• Well-adapted residents can lose adaptation and become ill.
• Symptoms: Headache, breathlessness, fatigue, insomnia, confusion.
• Risk Factors: Male, over 50 years old, overweight.

Oxygen Transport in Andean and Tibetan Highlanders

• Andean highlanders exhibit high lung capacity due to high VC. Also high hemoglobin concentration.
• Tibetan highlanders exhibit high blood flow to brain/extremities. Also elevated hypoxic ventilatory response.

Lecture 19: Immune Function, Hygiene Hypothesis, and Microbiome

• Immune system
• Innate immunity
• Adaptive immunity
• Antigen
• Autoimmune disease
• Hygiene hypothesis
• Microbiota
• Commensal relationship
• Symbiotic relationship
• Pathogenic relationship
• Gut microbiota functions

The Immune System

• Host defense system comprising biological structures and processes.
• Protects from infectious disease.
• Consists of innate and adaptive immunity.

Innate Immunity

• Defenses not dependent on prior exposure to disease.
• First line of defense against infection and injury
• Examples include mucosal membranes, antimicrobial proteins, phagocytic cells (like neutrophils), and inflammatory response.

Adaptive Immunity

• Acquired or specific immunity.
• Depends on prior exposure to antigens.
• Characterized by specificity, diversity, and memory.
• Includes T and B lymphocytes.

Autoimmune Disease

• Abnormal immune response to normal body parts
• Examples include celiac disease, type 1 diabetes, Graves' disease, inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis.

Hygiene Hypothesis

• All living things evolved with parasite exposure
• Early life bacterial and viral infections are important for immune maturation.
• Lack of infections in developed countries due to hygiene/antibiotics may cause immune system reactions to innocuous substances.

Riddled with Life: Friendly Worms, Ladybug Sex, and the Parasites that Make Us Who We Are

• Treating Crohn's Disease with worms
• Worms stimulate the Th-2 response to regulate Th-1 activity.
• Malfunctioning Th-1 response is characteristic of Crohn's disease.
• Hypothesis: Infecting with pig whipworms can regulate Th-1 activity for treating Crohn's Disease

Microbiota

• Ecological communities of commensal, symbiotic, and pathogenic microorganisms.
• Commensal: one species benefits, other is unaffected
• Symbiotic: both species benefit
• Pathogenic/parasitic: one species benefits, other is harmed.

Functions of the Gut Microbiota

• Immune function: Maintaining immunological balance through cross-talk with the immune system.
• Metabolism: Breaking down/absorbing nutrients, particularly carbohydrates.
• Communication with the brain: Microbiome-gut-brain axis, with biochemical signals influencing brain function.

Exam 2 Information (Summary)

• Dates and details for Exam 2 (review session, exam date)
• Also includes the start date for Unit 3 (human life history)