🦍Biological Anthropology Unit 9 – Human Biology and Health

Key Concepts and Terminology

• Anatomy studies the structure of the human body and its parts
• Physiology focuses on the functions and processes of the body and its systems
• Genetics is the study of heredity and the transmission of traits from parents to offspring
• Homeostasis maintains a stable internal environment in the body despite external changes
• Metabolism encompasses all chemical reactions in the body that convert food into energy and building blocks for growth and repair
• Immunity protects the body against infectious agents and foreign substances
• Anthropometry involves measuring and analyzing human body dimensions and proportions
• Epidemiology investigates the distribution, determinants, and control of health-related states or events in populations

Human Anatomy Basics

• The human body is organized into levels of increasing complexity: cells, tissues, organs, and systems
• Cells are the basic structural and functional units of life
  • Specialized cells perform specific functions (neurons transmit nerve impulses, muscle cells contract)
• Tissues are groups of similar cells that work together to perform a specific function
  • There are four main types of tissues: epithelial, connective, muscular, and nervous
• Organs are structures composed of two or more tissue types that perform a specific function (heart pumps blood, lungs facilitate gas exchange)
• Systems are groups of organs that work together to perform a complex function (digestive system breaks down food, circulatory system transports nutrients and oxygen)
• The skeletal system provides structure, support, and protection for the body
  • Consists of bones, cartilage, and ligaments
• The muscular system enables movement, maintains posture, and generates heat
  • Includes skeletal, smooth, and cardiac muscle tissues

Physiology and Body Systems

• The circulatory system transports nutrients, oxygen, and waste products throughout the body
  • Consists of the heart, blood vessels, and blood
  • The heart pumps blood through a network of arteries, capillaries, and veins
• The respiratory system facilitates gas exchange between the body and the environment
  • Includes the lungs, trachea, and diaphragm
  • Oxygen is taken in and carbon dioxide is expelled during breathing
• The digestive system breaks down food into nutrients that can be absorbed and used by the body
  • Consists of the mouth, esophagus, stomach, small intestine, large intestine, and accessory organs (liver, pancreas, gallbladder)
• The nervous system coordinates and controls body functions and responds to internal and external stimuli
  • Includes the brain, spinal cord, and a network of nerves
  • Neurons transmit electrical and chemical signals to process information and generate responses
• The endocrine system regulates body processes through the production and secretion of hormones
  • Glands secrete hormones directly into the bloodstream to target specific organs and tissues (thyroid gland regulates metabolism, adrenal glands produce stress hormones)
• The immune system defends the body against infectious agents and foreign substances
  • Consists of white blood cells, antibodies, and lymphatic organs (spleen, lymph nodes, thymus)
• The reproductive system enables the production of offspring and the continuation of the species
  • Male reproductive system includes the testes, penis, and prostate gland
  • Female reproductive system includes the ovaries, uterus, and mammary glands

Genetics and Inheritance

• Genes are segments of DNA that code for specific traits or characteristics
  • Alleles are alternative forms of a gene that can result in different phenotypes (eye color, blood type)
• Chromosomes are structures in the cell nucleus that contain DNA and genes
  • Humans have 23 pairs of chromosomes (46 total), with one set inherited from each parent
• Mendelian inheritance describes the transmission of traits controlled by single genes
  • Dominant alleles mask the expression of recessive alleles (brown eyes are dominant over blue eyes)
  • Punnett squares predict the probability of offspring inheriting specific traits based on parental genotypes
• Non-Mendelian inheritance involves traits controlled by multiple genes or influenced by environmental factors
  • Polygenic traits are determined by the combined effects of multiple genes (height, skin color)
  • Epigenetic modifications can alter gene expression without changing the underlying DNA sequence (DNA methylation, histone modifications)
• Mutations are changes in the DNA sequence that can lead to variations in traits or genetic disorders
  • Point mutations involve changes in a single nucleotide (sickle cell anemia)
  • Chromosomal mutations involve larger-scale changes (Down syndrome, caused by an extra copy of chromosome 21)
• Genetic disorders can be inherited or arise from de novo mutations
  • Single-gene disorders follow Mendelian inheritance patterns (cystic fibrosis, Huntington's disease)
  • Chromosomal disorders result from changes in chromosome number or structure (Turner syndrome, Klinefelter syndrome)

Human Growth and Development

• Prenatal development occurs from conception to birth and is divided into three stages: germinal, embryonic, and fetal
  • The germinal stage involves the formation and implantation of the zygote in the uterus
  • The embryonic stage is characterized by the development of major organ systems
  • The fetal stage is marked by rapid growth and maturation of organs and tissues
• Infancy and childhood are periods of rapid physical, cognitive, and social development
  • Motor skills develop in a predictable sequence (rolling over, sitting, crawling, walking)
  • Language acquisition progresses from babbling to single words to complex sentences
• Adolescence is a transitional period between childhood and adulthood characterized by puberty and sexual maturation
  • Hormonal changes lead to the development of secondary sexual characteristics (breast development, facial hair growth)
  • Cognitive development involves the maturation of abstract thinking and moral reasoning
• Adulthood is marked by the completion of physical growth and the achievement of sexual maturity
  • Early adulthood focuses on establishing identity, forming relationships, and pursuing education and career goals
  • Middle adulthood is characterized by a focus on family, work, and community responsibilities
  • Late adulthood involves adaptation to physical and cognitive changes and a reflection on life experiences
• Senescence refers to the gradual deterioration of physiological functions with age
  • Age-related changes include decreased muscle mass, bone density, and sensory acuity
  • Cognitive changes may include declines in processing speed and working memory

Nutrition and Metabolism

• Nutrients are substances in food that are essential for growth, development, and maintenance of health
  • Macronutrients provide energy and include carbohydrates, proteins, and fats
  • Micronutrients are required in smaller amounts and include vitamins and minerals
• Carbohydrates are the primary source of energy for the body
  • Simple carbohydrates include sugars (glucose, fructose) and are found in fruits, vegetables, and processed foods
  • Complex carbohydrates include starches and fibers and are found in whole grains, legumes, and vegetables
• Proteins are essential for building and repairing tissues and for the production of enzymes and hormones
  • Amino acids are the building blocks of proteins and can be classified as essential or non-essential
  • Complete proteins contain all essential amino acids (animal products, soy, quinoa)
• Fats provide energy, insulation, and protection for organs
  • Saturated fats are solid at room temperature and are found in animal products and tropical oils
  • Unsaturated fats are liquid at room temperature and are found in plant-based oils, nuts, and seeds
• Vitamins are organic compounds that are essential for specific bodily functions
  • Fat-soluble vitamins (A, D, E, K) are stored in the body and can accumulate to toxic levels
  • Water-soluble vitamins (B-complex, C) are not stored and must be consumed regularly
• Minerals are inorganic elements that are essential for various physiological processes
  • Macrominerals are required in larger amounts (calcium, phosphorus, magnesium)
  • Trace minerals are required in smaller amounts (iron, zinc, iodine)
• Metabolism refers to all chemical reactions in the body that convert food into energy and building blocks for growth and repair
  • Anabolism involves the synthesis of complex molecules from simpler ones (protein synthesis, glycogen storage)
  • Catabolism involves the breakdown of complex molecules into simpler ones (glycolysis, fatty acid oxidation)

Disease and Immunity

• Infectious diseases are caused by pathogenic microorganisms such as bacteria, viruses, fungi, and parasites
  • Transmission can occur through direct contact, respiratory droplets, contaminated food or water, or vectors (mosquitoes, ticks)
  • Examples include influenza, HIV/AIDS, malaria, and COVID-19
• Non-communicable diseases are not caused by infectious agents and are often related to lifestyle factors or genetics
  • Cardiovascular diseases affect the heart and blood vessels (coronary artery disease, stroke)
  • Cancer is characterized by the uncontrolled growth and spread of abnormal cells
  • Diabetes is a metabolic disorder characterized by high blood sugar levels
• The immune system defends the body against infectious agents and foreign substances
  • Innate immunity provides non-specific, rapid responses (skin barrier, inflammatory response)
  • Adaptive immunity provides specific, targeted responses and develops memory (antibodies, T cells)
• Vaccines stimulate the immune system to produce antibodies against specific pathogens
  • Attenuated vaccines contain weakened forms of the pathogen (measles, mumps, rubella)
  • Inactivated vaccines contain killed forms of the pathogen (polio, hepatitis A)
• Antibiotics are medications that kill or inhibit the growth of bacteria
  • Overuse or misuse of antibiotics can lead to the development of antibiotic-resistant strains
  • Antibiotic resistance is a growing public health concern that requires judicious use and the development of new antibiotics
• Epidemiology is the study of the distribution, determinants, and control of health-related states or events in populations
  • Incidence refers to the number of new cases of a disease in a population over a specified time period
  • Prevalence refers to the total number of cases of a disease in a population at a specific point in time

Environmental Influences on Human Health

• Environmental factors can have significant impacts on human health and disease risk
  • Air pollution is associated with respiratory and cardiovascular diseases (asthma, lung cancer, heart disease)
  • Water pollution can lead to waterborne illnesses (cholera, dysentery) and exposure to toxic substances (lead, mercury)
• Climate change is expected to have wide-ranging effects on human health
  • Extreme weather events (heatwaves, floods, hurricanes) can cause injury, displacement, and mental health issues
  • Changes in temperature and precipitation patterns can alter the distribution of vector-borne diseases (malaria, dengue fever)
• Urbanization and population density can influence the spread of infectious diseases
  • Close living quarters and shared public spaces facilitate the transmission of respiratory infections (influenza, tuberculosis)
  • Inadequate sanitation and hygiene in urban slums can lead to the spread of enteric diseases (cholera, typhoid fever)
• Occupational exposures can contribute to the development of specific health conditions
  • Exposure to hazardous chemicals (pesticides, solvents) can increase the risk of cancer and neurological disorders
  • Repetitive motions and awkward postures can lead to musculoskeletal disorders (carpal tunnel syndrome, back pain)
• Socioeconomic factors can influence access to healthcare, nutrition, and education, which in turn affect health outcomes
  • Poverty is associated with higher rates of chronic diseases, infectious diseases, and infant mortality
  • Social support networks and community engagement can promote mental health and resilience

Evolutionary Perspectives on Human Biology

• Evolutionary medicine applies evolutionary principles to understand the origins and persistence of human diseases
  • Many diseases are thought to result from mismatches between our evolutionary past and modern environments (obesity, type 2 diabetes)
  • Some genetic disorders may persist because they confer advantages in specific environments (sickle cell anemia and malaria resistance)
• Natural selection has shaped human physiology and behavior over millions of years
  • Adaptations that improved survival and reproduction in ancestral environments may not be optimal in modern contexts (preference for high-calorie foods)
  • Sexual selection has influenced the evolution of physical and behavioral traits that enhance reproductive success (male musculature, female waist-to-hip ratio)
• Comparative studies of human and non-human primates can provide insights into the evolution of human biology and behavior
  • Shared anatomical and physiological features reflect common evolutionary origins (opposable thumbs, color vision)
  • Differences in social structure and mating systems can shed light on the evolution of human pair-bonding and parental care
• The human microbiome, the collection of microorganisms that inhabit the human body, has co-evolved with humans over time
  • The gut microbiome plays a crucial role in digestion, immune function, and metabolism
  • Disruptions to the microbiome (dysbiosis) have been linked to various health conditions (inflammatory bowel disease, obesity)
• Epigenetic modifications, which alter gene expression without changing the underlying DNA sequence, can be influenced by environmental factors and may be heritable
  • Maternal nutrition and stress during pregnancy can affect the epigenome of the developing fetus, with potential long-term health consequences
  • Epigenetic changes may contribute to the intergenerational transmission of disease risk and the adaptation to changing environments