Anatomy & Physiology II: Comprehensive Final Exam Study Guide

Cardiovascular System

Blood

The blood is a specialized connective tissue that plays a vital role in transport, regulation, and protection. It consists of formed elements (cells and cell fragments) suspended in plasma, a liquid matrix containing proteins and solutes.

• Formed Elements: Include erythrocytes (red blood cells), leukocytes (white blood cells), and platelets. Each has distinct functions in oxygen transport, immunity, and clotting, respectively.

• Plasma: The fluid component of blood, making up about 55% of its volume. Contains water, electrolytes, nutrients, hormones, and waste products.

• Plasma Proteins: Major types include albumins (osmotic pressure), globulins (immunity), and fibrinogen (clotting).

• Hemopoiesis: The process of blood cell formation, occurring primarily in red bone marrow. Involves myeloid and lymphoid lineages, with key cells such as hemocytoblasts (stem cells), reticulocytes (immature RBCs), and megakaryocytes (platelet precursors). Regulated by hormones like erythropoietin and colony-stimulating factors.

• Hemoglobin: The oxygen-carrying protein in RBCs. Forms include oxyhemoglobin (bound to O2), deoxyhemoglobin (no O2), and carbaminohemoglobin (bound to CO2).

• RBC Breakdown: Occurs in the spleen, liver, and bone marrow. Hemoglobin is broken down into heme (converted to bilirubin) and globin (amino acids). Iron is recycled.

• Blood Typing: Based on surface antigens (A, B, Rh) and plasma antibodies. Compatibility is crucial for transfusions; mismatches cause agglutination and hemolysis.

• Hemostasis: The process of stopping bleeding, involving three phases: vascular spasm, platelet plug formation, and coagulation. Coagulation involves intrinsic, extrinsic, and common pathways, with key factors like Factor X, thrombin, fibrin, and plasmin (for fibrinolysis).

The Heart

The heart is a muscular organ responsible for pumping blood through the circulatory system. Its structure and function are closely linked to its role in maintaining circulation.

• Position and Anatomy: Located in the mediastinum, surrounded by the pericardium (parietal and visceral layers). Composed of four chambers (atria and ventricles), separated by valves (tricuspid, bicuspid/mitral, pulmonary, aortic).

• Internal Structures: Chordae tendineae and papillary muscles prevent valve prolapse. The interventricular septum separates the ventricles. The heart wall consists of epicardium, myocardium, and endocardium.

• Coronary Circulation: Arteries (right/left coronary, marginal, circumflex, anterior/posterior interventricular) supply the heart; veins (great/middle cardiac, coronary sinus) drain it.

• Cardiac Cycle: Includes systole (contraction) and diastole (relaxation). Valve openings/closings produce heart sounds. Chamber volumes and pressures change cyclically.

• Blood Flow: Blood flows from body → right atrium → right ventricle → pulmonary arteries → lungs → pulmonary veins → left atrium → left ventricle → aorta → body.

• Conduction System: Includes SA node, AV node, bundle of His, bundle branches, and Purkinje fibers. Responsible for automaticity and coordinated contraction. ECG components: P wave (atrial depolarization), QRS complex (ventricular depolarization), T wave (ventricular repolarization).

• Cardiac Output: Influenced by stroke volume, heart rate, venous return, end systolic/diastolic volumes, preload, afterload, and contractility. Cardiac reserve is the difference between resting and maximal output.

• Chemical Regulation: Natriuretic peptides decrease output; epinephrine/norepinephrine increase it; acetylcholine decreases it.

Blood Vessels and Circulation

Blood vessels transport blood throughout the body, facilitating exchange and maintaining homeostasis.

• Capillary Exchange: Determined by vessel structure and pressures (hydrostatic, osmotic, net filtration).

• Control of Blood Flow: Local autoregulation, neural (baroreceptor, chemoreceptor reflexes, sympathetic stimulation), and hormonal mechanisms adjust flow.

• Homeostatic Responses: To hemorrhage, shock, and exercise involve cardiovascular adjustments.

• Pulmonary and Systemic Circuits: Pulmonary circuit: right ventricle → pulmonary trunk → pulmonary arteries → lungs → pulmonary veins → left atrium. Systemic circuit: left ventricle → aorta → body → vena cavae → right atrium.

• Major Vessels: Includes arteries (aorta, carotids, subclavian, etc.) and veins (vena cavae, jugulars, saphenous, etc.).

• Venous Reserve and Anastomoses: Venous reserve is the extra blood in the venous system; anastomoses are connections between vessels providing alternate routes.

• Blood Flow Dynamics: Blood flow, pressure, velocity, vasodilation/constriction, and peripheral resistance are interrelated. Poiseuille's Law describes flow: $Q = \frac{\Delta P \pi r^4}{8 \eta l}$

Lymphatic System

Structure and Function

The lymphatic system returns interstitial fluid to the bloodstream, absorbs fats, and provides immune defense.

• Components: Lymph (fluid), lymphatic vessels, lymphatic tissues and organs (nodes, spleen, thymus, tonsils).

• Lymph Movement: Lymph forms from interstitial fluid, moves through lymphatic vessels, and drains into the right lymphatic duct (right upper body) or thoracic duct (rest of body).

• Major Tissues/Organs: Lymph nodes filter lymph; spleen filters blood; thymus matures T cells.

• Innate vs. Adaptive Defenses: Innate (nonspecific) defenses include barriers, phagocytes, surveillance, interferons, complement, inflammation, and fever. Adaptive (specific) immunity involves lymphocytes and memory.

• Nonspecific Defenses: Barriers (skin, mucosa), phagocytes (macrophages, neutrophils), immunological surveillance (NK cells), interferons, complement system, inflammation, and fever.

• Properties of Adaptive Immunity: Diversity, specificity, memory, and tolerance.

• Cell-Mediated vs. Antibody-Mediated Immunity: Cell-mediated (T cells) targets infected cells; antibody-mediated (B cells) targets extracellular pathogens.

• Antibodies: Y-shaped proteins with variable regions for antigen binding. Types include IgG, IgA, IgM, IgE, IgD.

• Inflammation: Characterized by redness, heat, swelling, and pain.

• Primary vs. Secondary Immune Response: Primary is slower, secondary is faster and stronger. Immunity can be active (natural or artificial) or passive (natural or artificial).

Respiratory System

Structure and Function

The respiratory system enables gas exchange, protects against pathogens, and regulates pH.

• Defense Mechanisms: Nasal hairs, mucus membranes, alveolar macrophages.

• Organs: Upper (nasal cavity, conchae, pharynx) and lower (larynx, trachea, bronchi, bronchioles, alveoli) respiratory tracts.

• Lungs: Consist of lobes, fissures, pleural membranes, and branching bronchi.

• External vs. Internal Respiration: External: alveoli ↔ pulmonary capillaries; Internal: systemic capillaries ↔ tissues.

• Ventilation: Inspiration and expiration involve diaphragm and intercostal muscles. Eupnea (quiet breathing) vs. hyperpnea (forced breathing).

• Factors Affecting Ventilation: Airway diameter, tissue compliance, rib cage mobility, alveolar surface tension.

• Gas Laws: Boyle's Law ($P_1V_1 = P_2V_2$), Dalton's Law, Henry's Law govern gas exchange.

• Respiratory Volumes: Tidal, expiratory reserve, inspiratory reserve, residual, inspiratory capacity, vital capacity, total lung capacity, functional residual capacity.

• Hemoglobin: Transports O2 and CO2. Forms: oxyhemoglobin, deoxyhemoglobin, carbaminohemoglobin.

• Oxygen Transport: Mostly bound to hemoglobin; factors affecting loading/unloading include pH, temperature, CO2 levels.

• CO2 Transport: Dissolved in plasma, as bicarbonate, or bound to hemoglobin.

• Control of Respiration: Local, neural (medulla, pons), reflexes (chemoreceptors, baroreceptors, Hering-Breuer), and voluntary control.

• Ventilation-Perfusion Coupling: Matches airflow to blood flow for efficient gas exchange.

Digestive System

Structure and Function

The digestive system breaks down food, absorbs nutrients, and eliminates waste.

• Organs: Oral cavity, pharynx, esophagus, stomach, small intestine, liver, gallbladder, pancreas, large intestine, peritoneum, omentum, mesenteries, mesocolon.

• Regulation: Local, neural (parasympathetic, sympathetic, reflexes), and hormonal (gastrin, secretin, CCK, GIP) controls.

• Oral Cavity: Teeth, salivary glands (parotid, submandibular, sublingual), tongue.

• Stomach: Regions (cardia, fundus, body, pylorus), sphincters, mucosa/muscularis layers, cells (chief, parietal, enteroendocrine), secretions (HCl, pepsinogen, intrinsic factor, gastrin, somatostatin), regulation (cephalic, gastric, intestinal phases).

• Small Intestine: Duodenum, jejunum, ileum, plicae circulares, villi, glands, microvilli, brush border, peristalsis, segmentation.

• Liver: Hepatic lobule, triad, hepatocytes, sinusoids, canaliculi, central vein, Kupffer cells. Functions: metabolic, hematological, digestive.

• Bile Pathway: Liver/gallbladder → common hepatic duct → common bile duct → cystic duct → ampulla/sphincter → small intestine.

• Pancreas: Islets (endocrine: insulin, glucagon), acini (exocrine: lipase, amylase, protease, peptidase, nucleases).

• Large Intestine: Mucosal glands, appendix, cecum, colon segments, rectum, anal canal. Functions: water absorption, feces formation, defecation.

• Chemical Breakdown: Carbohydrates, proteins, and fats are digested and absorbed at specific locations by specific enzymes; emulsification aids fat digestion.

Metabolism

Metabolic Pathways and Regulation

Metabolism encompasses all chemical reactions in the body, including energy production and nutrient processing.

• Carbohydrate Metabolism: Gluconeogenesis (glucose synthesis), glycogenesis (glycogen formation), glycogenolysis (glycogen breakdown).

• Protein Metabolism: Synthesis, transamination, deamination, urea cycle. Essential vs. nonessential amino acids.

• Lipid Metabolism: Beta oxidation (fatty acid breakdown), lipolysis, lipogenesis, ketoacidosis, essential fatty acids.

• Absorptive vs. Post-Absorptive States: Absorptive (nutrient storage, insulin), post-absorptive (nutrient mobilization, glucagon, epinephrine).

• Nutrients: Carbohydrates, proteins, lipids, vitamins, minerals, water. Each has specific roles and caloric values.

• Metabolic Rate: Influenced by age, sex, activity, hormones. Basal metabolic rate (BMR) is the energy used at rest.

• Thermoregulation: Maintenance of body temperature via heat production and loss mechanisms.

Urinary System

Structure and Function

The urinary system removes waste, regulates fluid and electrolyte balance, and maintains acid-base homeostasis.

• Organs: Kidneys, ureters, urinary bladder, urethra.

• Kidney Anatomy: Hilum, cortex, medulla, pyramids, columns, papilla, calyces, pelvis.

• Nephron: Glomerulus, afferent/efferent arterioles, capsule, proximal/distal convoluted tubules, nephron loop, collecting duct, juxtamedullary complex.

• Glomerular Filtration: Driven by hydrostatic and osmotic pressures. Glomerular filtration rate (GFR) is regulated by blood pressure and filtration surface area.

• Reabsorption and Secretion: Occur along nephron segments via various transport mechanisms.

• Urine Concentration: Nephron loop, vasa recta, and tubule permeability create dilute or concentrated urine.

• Hormonal/Neural Control: ADH, aldosterone, natriuretic peptides, renin, angiotensin II regulate homeostasis and urine production.

• Lower Tract Anatomy: Ureters, bladder (detrusor muscle, trigone), urethra (internal/external sphincters, male/female differences).

• Micturition Reflex: Involuntary and voluntary control of urination.

Fluid, Electrolyte, and Acid-Base Balance

Homeostasis and Regulation

Maintaining fluid, electrolyte, and acid-base balance is essential for normal cellular function.

• Fluid Compartments: Intracellular (inside cells) vs. extracellular (plasma, interstitial). Fluid shifts depend on osmotic and hydrostatic forces.

• Fluid Balance: Entry via ingestion/metabolism; loss via urine, sweat, feces, respiration. Responses to dehydration/overhydration involve hormonal and neural mechanisms.

• Electrolyte Balance: Sodium, potassium, calcium imbalances (hyper/hyponatremia, hyper/hypokalemia, hyper/hypocalcemia) affect nerve/muscle function.

• Hormonal Regulation: Aldosterone, ADH, angiotensin II, natriuretic peptides, calcitriol, parathyroid hormone, calcitonin.

• Acid-Base Balance: Normal blood pH: 7.35–7.45. Buffers (protein, bicarbonate/hemoglobin, phosphate) maintain pH.

• Acidosis/Alkalosis: Respiratory (hypercapnia/hypocapnia) and metabolic causes; compensation by respiratory and urinary systems.

Reproductive System

Male and Female Anatomy and Physiology

The reproductive system ensures species continuity through gamete production, fertilization, and support of offspring.

• Male Structures: Scrotum, testis (tunica albuginea, seminiferous tubules), epididymis, ductus deferens, ejaculatory duct, urethra, penis, glands (seminal, prostate, bulbo-urethral).

• Female Structures: Ovary, uterine tube, uterus (perimetrium, myometrium, endometrium), vagina, external genitalia, mammary gland.

• Spermatogenesis: Spermatogonium → primary/secondary spermatocyte → spermatid → spermatozoa. Interstitial and nurse cells support development.

• Sperm Pathway: Seminiferous tubules → epididymis → ductus deferens → ejaculatory duct → urethra. Glandular secretions aid sperm function.

• Hormonal Control (Male): GnRH, LH, FSH, testosterone, inhibin, ABP.

• Oogenesis: Oogonium → primary/secondary oocyte → ovum. Follicle development: primordial → primary → secondary → tertiary → corpus luteum/ albicans.

• Hormonal Control (Female): GnRH, FSH, LH, estrogens, inhibin, progesterone.

• Ovarian/Uterine Cycles: Follicular, luteal, menses, proliferative, secretory phases.

• Fertilization: Sperm travel through female tract to reach oocyte; ejaculate contains protective factors.

Development and Heredity

Fertilization and Pregnancy

Development begins with fertilization and continues through gestation, involving complex physiological changes.

• Fertilization: Sperm and oocyte unite to form a zygote, which travels to the uterus and implants.

• Placenta: Forms to support fetal development, providing nutrients, gas exchange, and waste removal.

• Maternal Changes: Pregnancy alters reproductive, endocrine, cardiovascular, respiratory, digestive, and urinary systems.

• Labor: Involves dilation, expulsion, and placental stages. Regulated by hormones; complications include premature labor, difficult deliveries, and multiple births.