Anatomy & Physiology Study Guide: Cardiovascular, Lymphatic, Respiratory, Digestive, Metabolic, Urinary, Fluid/Electrolyte, Reproductive, and Developmental Systems

Cardiovascular System: Blood Vessels and Hemodynamics

Structure and Function of Blood Vessels

The cardiovascular system consists of arteries, arterioles, capillaries, venules, and veins, each with distinct structural and functional characteristics.

• Arteries: Thick-walled vessels that carry blood away from the heart under high pressure.

• Arterioles: Smaller branches of arteries that regulate blood flow into capillaries.

• Capillaries: Thin-walled vessels facilitating exchange of gases, nutrients, and wastes.

• Venules: Small vessels collecting blood from capillaries and channeling it to veins.

• Veins: Vessels with thinner walls than arteries, returning blood to the heart under lower pressure.

Example: Blood flows from the heart through arteries, arterioles, capillaries, venules, and veins, completing the circuit.

Capillary Exchange

Capillary exchange is the process by which substances move between blood and interstitial fluid.

• Diffusion: Movement of molecules from high to low concentration.

• Transcytosis: Transport of large molecules via vesicles across endothelial cells.

• Bulk Flow: Movement of fluid driven by pressure differences.

Example: Oxygen diffuses from capillaries into tissues, while carbon dioxide diffuses in the opposite direction.

Hemodynamics and Blood Pressure Regulation

Hemodynamics refers to the dynamics of blood flow, influenced by vessel diameter, blood viscosity, and total vessel length.

• Mean Arterial Pressure (MAP): Average pressure in arteries during one cardiac cycle.

• Systemic Vascular Resistance (SVR): Resistance offered by systemic blood vessels.

• Blood Pressure Equation:

$\text{MAP} = \text{CO} \times \text{SVR}$

• Pulse: Rhythmic expansion of an artery due to heartbeat.

• Systolic Pressure: Maximum pressure during ventricular contraction.

• Diastolic Pressure: Minimum pressure during ventricular relaxation.

• Pulse Pressure: Difference between systolic and diastolic pressures.

$\text{Pulse Pressure} = \text{Systolic} - \text{Diastolic}$

Shock and Circulatory Regulation

Shock is a condition of inadequate cardiac output resulting in insufficient tissue perfusion.

• Types of Shock: Hypovolemic, cardiogenic, vascular, and obstructive.

• Negative Feedback: Body responds to shock by activating compensatory mechanisms to restore homeostasis.

Principal Blood Vessels and Special Circulations

The aorta and its branches, systemic veins, and special circulations (hepatic portal, pulmonary, fetal) are key components.

• Aorta Divisions: Ascending, arch, thoracic, and abdominal.

• Major Arteries: Coronary arteries (ascending), brachiocephalic, left common carotid, left subclavian (arch).

• Systemic Veins: Superior vena cava, inferior vena cava, coronary sinus.

• Special Circulations: Hepatic portal system (liver), pulmonary circulation (lungs), fetal circulation (developing fetus).

Example: The hepatic portal system transports nutrients from the GI tract to the liver for processing.

Lymphatic System and Immunity

Components and Functions of the Lymphatic System

The lymphatic system includes lymph, lymphatic vessels, lymph nodes, and organs (tonsils, spleen, thymus).

• Lymph: Fluid similar to plasma, containing white blood cells.

• Lymphatic Vessels: Transport lymph from tissues to the bloodstream.

• Lymph Nodes: Filter lymph and house immune cells.

• Organs: Tonsils (protect against inhaled pathogens), spleen (filters blood), thymus (T cell maturation).

Immunity: Innate and Adaptive

Immunity is the body's ability to resist disease. It is classified as innate (nonspecific) or adaptive (specific).

• Innate Immunity: General defenses (skin, mucous membranes, phagocytes, natural killer cells).

• Adaptive Immunity: Specific responses involving B cells (antibody-mediated) and T cells (cell-mediated).

Example: Vaccination stimulates adaptive immunity by exposing the body to antigens.

Immune Responses and Surveillance

• Antigen: Substance that triggers an immune response.

• Antibody: Protein produced by B cells that binds to antigens.

• Cell-Mediated Immunity: T cells attack infected or abnormal cells.

• Antibody-Mediated Immunity: B cells produce antibodies to neutralize pathogens.

• Immunological Surveillance: Monitoring for abnormal cells (e.g., cancer).

Respiratory System

Anatomy and Physiology of Respiratory Organs

The respiratory system includes the nose, pharynx, larynx, trachea, bronchi, and lungs, each with specific functions.

• Nose: Filters, warms, and moistens air.

• Pharynx: Passageway for air and food.

• Larynx: Voice production and airway protection.

• Trachea: Conducts air to bronchi.

• Bronchi: Branches leading to lungs.

• Lungs: Site of gas exchange.

Pulmonary Ventilation and Gas Exchange

Ventilation involves inhalation and exhalation, driven by pressure changes.

• Tidal Volume: Amount of air inhaled/exhaled per breath.

• Inspiratory/Expiratory Reserve Volume: Additional air inhaled/exhaled beyond tidal volume.

• Residual Volume: Air remaining after maximal exhalation.

Gas Laws: Dalton's law (partial pressures), Henry's law (gas solubility).

Example: Oxygen and carbon dioxide exchange occurs in alveoli and tissues.

Transport and Control of Respiration

• Oxygen Transport: Bound to hemoglobin in red blood cells.

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

• Control: Nervous system regulates breathing rate and depth.

Digestive System

Organs and Processes of Digestion

The digestive system includes the GI tract and accessory organs (salivary glands, liver, pancreas, gallbladder).

• GI Tract: Mouth, pharynx, esophagus, stomach, small and large intestines.

• Accessory Organs: Aid in digestion via secretions.

Processes: Ingestion, propulsion, mechanical digestion, chemical digestion, absorption, and defecation.

Histology and Regulation

• Layers: Mucosa, submucosa, muscularis, serosa.

• Nerve Supply: Enteric nervous system regulates motility and secretion.

• Hormonal Control: Hormones (e.g., gastrin, secretin) regulate digestive activities.

Metabolism and Nutrition

Metabolic Processes and Energy Production

Metabolism includes all chemical reactions in the body, divided into anabolism (building up) and catabolism (breaking down).

• ATP: Main energy currency; produced during catabolic reactions and used in anabolic reactions.

• Oxidation–Reduction: Electron transfer reactions essential for energy production.

$\text{ATP} \rightarrow \text{ADP} + \text{P}_i + \text{Energy}$

Carbohydrate, Lipid, and Protein Metabolism

• Carbohydrates: Broken down to glucose for energy.

• Lipids: Transported by lipoproteins; used for energy or stored.

• Proteins: Broken down to amino acids; used for synthesis or energy.

Absorptive and Postabsorptive States

• Absorptive State: Nutrients are absorbed and stored.

• Postabsorptive State: Stored nutrients are mobilized for energy.

Nutrition and Body Heat

• Minerals and Vitamins: Essential for metabolic reactions.

• Metabolic Rate: Influenced by age, sex, activity, and hormones.

• Heat Transfer: Conduction, convection, radiation, evaporation.

Urinary System

Anatomy and Physiology

The urinary system includes kidneys, ureters, urinary bladder, and urethra, maintaining homeostasis of blood composition, volume, pH, and pressure.

• Kidneys: Filter blood, form urine.

• Nephron: Functional unit; consists of glomerulus, tubules, and collecting duct.

Urine Formation

• Glomerular Filtration: Blood pressure forces water and solutes out of glomerulus.

• Tubular Reabsorption: Return of water and solutes to blood.

• Tubular Secretion: Addition of substances to urine.

Example: Diuretics increase urine output by inhibiting reabsorption.

Fluid, Electrolyte, and Acid–Base Homeostasis

Fluid Compartments and Electrolytes

Body fluids are distributed between intracellular fluid (ICF) and extracellular fluid (ECF).

• ICF: Inside cells.

• ECF: Includes plasma and interstitial fluid.

Electrolyte Functions

• Sodium, Chloride, Potassium, Bicarbonate, Calcium, Phosphate, Magnesium: Maintain osmotic balance, nerve function, muscle contraction, and pH.

Acid–Base Balance

• Buffers: Stabilize pH.

• Respiratory Regulation: Exhalation of CO2 affects pH.

• Renal Regulation: Kidneys excrete H+ to maintain pH.

Example: Metabolic acidosis occurs when excess acid accumulates in the body.

Reproductive Systems

Anatomy and Physiology

The reproductive systems include male and female organs, each with specialized functions.

• Male: Testes (spermatogenesis), ducts, accessory glands, penis.

• Female: Ovaries (oogenesis), ducts, uterus, vagina, external genitalia.

Cycles and Sexual Response

• Ovarian Cycle: Follicular development, ovulation, corpus luteum formation.

• Uterine Cycle: Menstrual, proliferative, and secretory phases.

• Sexual Response: Physiological changes during intercourse.

Development and Inheritance

Prenatal Development and Maternal Changes

Development begins with fertilization and continues through embryonic and fetal periods.

• Trimesters: Three stages of prenatal development.

• Major Events: Cell division, differentiation, organ formation.

• Maternal Changes: Hormonal, anatomical, and physiological adaptations during pregnancy.

Labor, Birth, and Lactation

• Labor: Three stages—dilation, expulsion, placental.

• Infant Adjustments: Respiratory and cardiovascular changes at birth.

• Lactation: Milk production regulated by hormones.

Additional info:

These notes expand on chapter objectives and provide academic context for each system, suitable for exam preparation.