Anatomy & Physiology: Chapters 20-29

• These are study notes for Chapters 20-29

Chapter 20: Structure and Function of Animal Bodies

• Anatomy is the study of structure and organization in living things
• Physiology details how structures function
• An example is the heart's chambers (anatomy) and its blood-pumping action (physiology)

Tissues of the Body

• Epithelial tissue protects, covers body surfaces, and lines organs
• Connective tissue supports and binds structures like bone, blood, and cartilage
• Muscle tissue enables movement via skeletal, smooth, and cardiac muscles
• Nervous tissue transmits electrical signals for communication

Control Systems

• Negative feedback maintains homeostasis
• Negative feedback counteracts changes, like body temperature regulation
• Positive feedback amplifies change until completion, such as childbirth contractions

Body Systems Overview

• The digestive system breaks down food and absorbs nutrients
• The circulatory system transports oxygen, nutrients, and waste
• The respiratory system facilitates gas exchange
• The nervous system coordinates body responses via electrical signals
• The endocrine system produces hormones that regulate body functions
• The skeletal system provides structure, support, and organ protection
• The muscular system enables movement through contractions
• The immune system defends against infections and diseases
• The excretory system removes waste and maintains fluid balance
• The reproductive system produces offspring

Chapter 21: Nutrition and Digestion

Types of Feeding

• Suspension feeders filter food from water
• Whales are suspension feeders
• Substrate feeders live on or in their food source
• Caterpillars are substrate feeders
• Fluid feeders consume liquid nutrients
• Mosquitoes are fluid feeders
• Bulk feeders eat large food pieces
• Humans are bulk feeders

Four Stages of Food Processing

• Ingestion involves taking in food
• Digestion is breaking down food mechanically and chemically
• Absorption is the uptake of nutrients into the bloodstream
• Elimination is expelling undigested materials

Digestive System Organs and Functions

• The oral cavity begins mechanical and chemical digestion
• The stomach uses acidic gastric juices to break down proteins
• The small intestine is the main site for nutrient absorption
• The large intestine absorbs water and forms waste
• The rectum and anus store and expel waste

Common Digestive Issues

• Acid reflux is stomach acid backing up into the esophagus
• Gastric ulcers are sores in the stomach lining, often from bacteria
• Diarrhea and constipation result from imbalances in water absorption

Nutritional Needs

• Kilocalories measure food energy, with 1 kcal equaling 1,000 calories
• Metabolic rate is the body's total energy use
• Basal Metabolic Rate (BMR) is the energy needed for basic functions at rest

Essential Nutrients

• Essential fatty acids are in seeds, nuts, and fish
• Essential amino acids are obtained from proteins in meat, eggs, and dairy
• Vitamins are organic molecules needed for biochemical reactions
• Minerals are inorganic elements for body functions

Health & Nutrition

• Food labels show serving size, calories, and nutrient breakdown
• Malnutrition is a deficiency in nutrients or energy
• Obesity indicates excess body fat
• Body Mass Index (BMI) equals weight (kg) / height (m)^2

LDL vs. HDL

• LDL ("bad" cholesterol) leads to artery blockage
• HDL ("good" cholesterol) helps remove excess cholesterol

Chapter 22: Gas Exchange and the Respiratory System

Introduction to Gas Exchange

• Gas exchange involves swapping oxygen (O₂) and carbon dioxide (CO₂)
• Oxygen is needed for cellular respiration (energy)
• Carbon dioxide must be removed to maintain pH balance
• Smoking and vaping can damage lung tissues, leading to respiratory problems

Mechanisms of Gas Exchange

• Breathing involves inhaling oxygen and exhaling carbon dioxide
• Transport involves blood carrying oxygen to cells and removing carbon dioxide
• Cellular exchange involves cells using for ATP and releasing carbon dioxide

Respiratory Surfaces

• Respiratory surfaces must be thin and moist for gas diffusion
• Earthworms use skin for respiration
• Fish utilize gills
• Insects employ a tracheal system
• Mammals have lungs

Gas Exchange in Different Organisms

• Gills use countercurrent flow to maximize uptake
• Tracheal systems deliver air directly to cells in insects
• Lungs use alveoli to transfer gases with blood

Human Respiratory System

• Pathway: Nostrils → Nasal Cavity → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli
• The diaphragm helps move air in/out of lungs
• Mucus and cilia trap harmful particles
• Surfactants prevent alveoli from collapsing

Breathing Mechanism

• Inhale = diaphragm contracts
• Exhale = diaphragm relaxes
• The brain controls breathing rate based on carbon dioxide levels

Transport of Gases in Blood

• Oxygen is carried by hemoglobin in red blood cells
• Carbon dioxide is carried dissolved, bound to hemoglobin, or as bicarbonate (HCO₃⁻)
• Gases move from high to low pressure areas

Chapter 23: Circulatory System and Blood

Circulatory Systems

• In an open system, fluid moves over organs (insects)
• In a closed system, blood circulates through vessels (humans)

Evolution of Vertebrate Circulation

• Fish have a 2-chambered heart (single loop)
• Amphibians/Reptiles have a 3-chambered heart
• Birds/Mammals have a 4-chambered heart

Human Circulation

• Pulmonary circuit involves Heart → Lungs → Heart
• Systemic Circuit involves Heart → Body → Heart
• Blood flow: Body → Right Heart → Lungs → Left Heart → Body

Cardiac Cycle

• Diastole: The heart relaxes and fills with blood
• Systole: The heart contracts and pumps blood
• The SA Node starts the heartbeat

Heart Diseases

• Heart attack: Blocked coronary artery
• Stroke: Blocked or burst artery in the brain
• Atherosclerosis: Plaque buildup in arteries

Blood Vessels

• Arteries have thick walls and high pressure
• Veins have thinner walls and valves
• Capillaries are thin to facilitate gas/nutrient exchange

Blood Pressure

• Systolic (when heart beats) / Diastolic (when relaxed)
• Normal blood pressure is ~120/80 mmHg
• Hypertension is high blood pressure

Blood Components

• Plasma carries nutrients and hormones
• Red Blood Cells (RBCs) carry oxygen
• White Blood Cells (WBCs) fight infection
• Platelets help blood clot

Blood Disorders

• Anemia is a low RBC count (fatigue)
• Leukemia is cancer of WBCs
• The EPO hormone stimulates RBC production

Blood Clotting

• Platelets stick to injury
• Fibrin helps form a clot

Stem Cells in Blood

• Stem cells are in bone marrow
• Stem cells produce all blood cells
• Bone marrow transplants can treat diseases like leukemia

Chapter 24: The Immune System & Disease Defense

• The immune system defends against bacteria, viruses, fungi, and parasites
• Vaccines stimulate immune memory for long-term protection
• Herd immunity protects vulnerable populations

Innate Immunity (First Line of Defense)

• Physical barriers include the skin and mucous membranes
• Phagocytes (neutrophils, macrophages) engulf invaders
• Natural killer cells destroy virus-infected/cancerous cells
• The inflammatory response involves swelling, heat, and pain to fight infections

Adaptive Immunity (Specific Defense)

• Antigens are foreign molecules triggering immune responses
• The humoral response involves B cells creating antibodies to neutralize pathogens
• The cell-mediated response involves T cells attacking infected cells
• Memory cells provide long-term immunity for quicker future responses

Lymphatic System & Immunity

• Lymph nodes filter and trap pathogens
• The spleen removes old blood cells and stores immune cells
• The thymus matures T cells

Immune System Malfunctions

• Allergies are overreactions to harmless substances
• Autoimmune diseases involve the body attacking itself (e.g., Type 1 diabetes, lupus)
• Immunodeficiency is a weak immune system
• HIV destroys helper T cells

Chapter 25: Homeostasis & Excretion

Thermoregulation (Body Temperature Control)

• Endotherms (warm-blooded) generate heat internally
• Birds and mammals are endotherms
• Ectotherms (cold-blooded) rely on external heat sources
• Reptiles and fish are ectotherms

Adaptations for Temperature Control

• Heat retention involves fur, feathers, and fat
• Heat loss involves sweating, panting, and vasodilation
• Behavioral adjustments involve hibernation, migration, and seeking shade

Osmoregulation (Water & Salt Balance)

• Osmoconformers match their internal solute levels to the environment
• Jellyfish are osmoconformers
• Osmoregulators balance internal water/salt levels
• Freshwater fish and humans are osmoregulators

Nitrogenous Waste Disposal

• Ammonia is toxic and easily excreted by aquatic animals
• Urea is less toxic and requires energy (mammals, amphibians)
• Uric acid is least toxic and excreted as paste to conserve water (birds, reptiles)

Urinary System

• Kidneys filter blood
• Kidneys regulate water/salt balance
• Nephrons filter blood into urine

Urine Formation

• Filtration occurs when blood pressure pushes fluids into nephron
• Reabsorption occurs when nutrients, water, and salts return to blood
• Secretion occurs when unneeded substances are added to filtrate
• Excretion involves urine being expelled

Kidney Dialysis

• Used for kidney failure
• Hemodialysis filters blood through a machine
• Peritoneal dialysis filters blood internally using the body's membrane

Chapter 26: Hormones and the Endocrine System

Two Communication Systems

• The nervous system uses fast electrical signals via neurons
• Short-term, targeted effects
• The endocrine system uses slower chemical signals called hormones
• Long-lasting, widespread effects

How Hormones Work

• Reception involves a hormone binding to a specific receptor on a target cell
• Signal transduction involves a message relayed inside the cell
• Response involves a cell behavior change (e.g., gene activation/inhibition)

Major Endocrine Glands & Functions

• The hypothalamus and pituitary are the control center
• The pituitary directs other glands
• The thyroid regulates metabolism and development
• The pancreas manages blood sugar
• The adrenal glands respond to stress

Maintaining Homeostasis

• Sensors detect imbalance
• Hormones are released
• Target cells respond
• The body returns to balance

Blood Sugar Regulation

• High blood sugar is lowered by insulin
• Low blood sugar is raised by glucagon -

Common Endocrine Disorders

• Diabetes Mellitus: The lack of insulin production or response
• Thyroid Disorders: Over/underactive thyroid affects metabolism
• Adrenal Disorders: Abnormal cortisol levels affect mood and blood pressure

Hormones Through Life Stages

• Development involves growth hormone and thyroid hormones
• Puberty involves sex hormones
• Adulthood involves hormones maintaining functions and fertility
• Aging involves a gradual decrease in hormone production

Chapter 27: Reproduction and Embryonic Development

Types of Reproduction

• Asexual Reproduction: One parent, genetically identical offspring
• Sexual Reproduction: Two parents, genetically unique offspring

Genetic Variation in Sexual Reproduction

• Combines DNA from both parents
• Gametes are haploid (n)
• Sperm is small and motile
• Egg is large and nutrient-rich
• Zygote is diploid (2n)
• Increases adaptability and reduces the risk of genetic disorders

Human Reproductive Systems

• Female: Ovaries, oviducts, uterus, vagina
• Male: Testes, epididymis, vas deferens, glands
• Shared purpose: produce, transport, and unite gametes

Gamete Formation (Meiosis)

• Reduces chromosome number by half
• Spermatogenesis is continuous
• Oogenesis completes after fertilization

Fertilization & Zygote Formation

• Enzymes help sperm penetrate egg
• Membranes fuse
• Nuclei unite
• Zygote (2n) forms
• The egg blocks other sperm after fertilization

Cleavage and Gastrulation

• Cleavage involves rapid cell division
• Cleavage forms blastula
• Gastrulation involves cells migrating to form germ layers

Stages of Labor & Birth

• Cervix Dilation: Contractions begin
• Expulsion: Baby delivered through birth canal
• Placenta Delivery: Afterbirth expelled
• Controlled by estrogen and oxytocin in a positive feedback loop

Reproductive Technologies

• IVF (In Vitro Fertilization): Fertilization in lab; embryo implanted in uterus
• Used for infertility
• Raises ethical questions

Sexually Transmitted Infections (STIs)

• Bacterial STIs: Treatable
• Viral STIs: Incurable, managed
• Often asymptomatic
• Regular testing is key
• Can lead to infertility, chronic pain, higher HIV risk

Chapter 28: Nervous Systems

Body Response Coordination

• The nervous system uses fast, electrical signals (e.g., reflexes)
• The endocrine system uses slower, hormonal signals (e.g., puberty)

Organization of the Nervous System

• Central Nervous System (CNS) uses the brain and spinal cord
• Peripheral Nervous System (PNS) uses nerves outside CNS
• Sensory Neurons carry signals to CNS
• Motor Neurons carry signals from CNS to muscles/glands

How Neurons Work

• Electrical signals travel down the axon
• Dendrites receive signals
• Cell body processes
• Axon sends signal

Neural Communication (Synapses)

• Synapse: Gap between neurons
• Chemical Synapse: Neurotransmitters cross gap
• Electrical Synapse: Direct signal (rare)
• Neurotransmitters bind to receptors on the next neuron

Major Neurotransmitters

• Serotonin affects mood and sleep
• Dopamine affects reward and attention
• Acetylcholine affects muscle movement
• Norepinephrine affects alertness

Drug Effects on the Brain

• SSRIs raise serotonin levels
• Caffeine stimulates brain activity
• Alcohol slows brain activity
• Drugs can mimic, block, or enhance neurotransmitters

Nervous System Evolution

• Simple Animals: Nerve nets
• Intermediate Animals: Start of centralization
• Complex Animals: Cephalization
• Advanced Animals: Brain with specialized regions

Human Brain Structure

• Forebrain (Cerebrum): Thought and emotion
• Midbrain: Sensory processing
• Hindbrain (Cerebellum): Movement and balance
• Cerebral Cortex: Learning, memory, voluntary movement

Brain and Behavior

• Memory: Short-term → long-term
• Sleep: Active brain state for memory and restoration
• Plasticity: Brain can rewire
• Disorders such as Alzheimer’s, Parkinson’s and schizophrenia affect brain structure or chemistry

Chapter 29: The Senses

Sensory Reception and Signaling

• Detect: Receptors sense stimuli
• Convert: Signals turned into electrical impulses
• Process: Brain interprets signals
• Adapt: Brain filters constant or unimportant stimuli

Types of Sensory Receptors

• Thermoreceptors detect temperature
• Mechanoreceptors detect pressure and motion
• Chemoreceptors detect chemical changes
• Electromagnetic Receptors detect light and magnetic fields

Hearing and Balance

• The outer ear captures sound
• The middle ear's vibrations move bones
• The inner ear's fluid moves hair cells
• The brain interprets sound and head position

Vision Across Species

• Compound Eyes use many lenses
• Human Eyes adjust lens shape for focus
• Simple Eyes detect light direction
• Cephalopod Eyes move the lens to focus

Taste and Smell

• The five tastes are sweet, salty, sour, bitter, and umami
• Smell uses 400+ types of receptors to detect thousands of odors
• Flavor is 80% smell

From Sensation to Action

• Stimulus Detection: Sensory receptors activated
• Signal Transmission: Carried by neurons to CNS
• Processing: Brain interprets data
• Response: Motor neurons activate a response