Comprehensive Study Guide: Anatomy & Physiology Exam Topics

Chapter 12 – Muscles

Types and Structure of Muscle Tissue

Muscle tissue is essential for movement, posture, and heat production. There are three main types, each with unique structural and functional characteristics.

• Skeletal muscle: Voluntary, striated, attached to bones, responsible for body movement.

• Cardiac muscle: Involuntary, striated, found only in the heart, responsible for pumping blood.

• Smooth muscle: Involuntary, non-striated, found in walls of hollow organs, controls movement of substances.

• Key terms: myocyte, myosin, actin, sacromere, troponin, titin, sarcoplasm

Example: Skeletal muscle contracts to move limbs, while cardiac muscle contracts rhythmically to pump blood.

Sliding Filament Theory

The sliding filament theory explains how muscles contract at the molecular level.

• Process: Myosin heads bind to actin filaments, pulling them inward, shortening the sarcomere.

• Steps: ATP binds to myosin, myosin detaches from actin, hydrolyzes ATP, reattaches, and pulls actin.

• Equation: $\text{Force} = \text{Number of cross-bridges} \times \text{Force per cross-bridge}$

Motor Unit and Muscle Contraction

A motor unit consists of a motor neuron and all the muscle fibers it innervates.

• Recruitment: Increasing the number of active motor units increases muscle force.

• Tetanus: Sustained contraction due to rapid stimulation.

Types of Muscle Contraction

• Isometric: Muscle length does not change.

• Isotonic: Muscle changes length (concentric or eccentric).

Comparison of Muscle Types

• Skeletal vs. Cardiac vs. Smooth: Skeletal is voluntary and striated; cardiac is involuntary and striated; smooth is involuntary and non-striated.

• Location: Skeletal (bones), cardiac (heart), smooth (organs).

Chapter 14 – Cardiovascular Physiology

Cardiac Cycle and Output

The cardiac cycle describes the sequence of events in one heartbeat, including contraction (systole) and relaxation (diastole).

• Stroke volume: Amount of blood pumped per beat.

• Cardiac output: $\text{CO} = \text{Stroke Volume} \times \text{Heart Rate}$

• Factors affecting output: Preload, afterload, contractility.

Blood Flow and Pressure

• Blood pressure: Force exerted by blood on vessel walls.

• Hypertension: Chronically elevated blood pressure.

• Orthostatic hypotension: Drop in blood pressure upon standing.

Heart Sounds and Electrical Activity

• EKG/ECG: Measures electrical activity of the heart.

• P wave: Atrial depolarization.

• QRS complex: Ventricular depolarization.

• T wave: Ventricular repolarization.

Chapter 15 – Blood and the Control of Blood Pressure

Blood Components and Functions

Blood is a connective tissue composed of plasma and formed elements (red cells, white cells, platelets).

• Plasma: Water, proteins, nutrients, hormones.

• Red blood cells: Carry oxygen via hemoglobin.

• White blood cells: Immune defense.

• Platelets: Clotting.

Blood Pressure Regulation

• Baroreceptors: Detect changes in blood pressure.

• Kidneys: Regulate blood volume via renin-angiotensin system.

• Hypertension: High blood pressure; risk factor for heart disease.

• Orthostatic hypotension: Sudden drop in blood pressure when standing.

Chapter 17 – Mechanics of Breathing

Respiratory System Functions

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

• Primary functions: Oxygen intake, carbon dioxide removal.

• Ventilation: Movement of air in and out of lungs.

• Surfactant: Reduces surface tension in alveoli.

Respiratory Volumes and Capacities

• Tidal volume: Air moved per breath.

• Vital capacity: Maximum air exhaled after maximum inhalation.

• Equation: $\text{Vital Capacity} = \text{Tidal Volume} + \text{Inspiratory Reserve Volume} + \text{Expiratory Reserve Volume}$

Chapter 18 – Gas Exchange and Transport

Gas Exchange Mechanisms

Gas exchange occurs in the alveoli, driven by partial pressure gradients.

• Oxygen transport: Bound to hemoglobin, dissolved in plasma.

• Carbon dioxide transport: Dissolved, bound to hemoglobin, as bicarbonate.

• Equation: $\text{CO}_2 + \text{H}_2\text{O} \leftrightarrow \text{H}_2\text{CO}_3 \leftrightarrow \text{H}^+ + \text{HCO}_3^-$

Chapter 19 – The Kidneys

Renal Function and Filtration

The kidneys filter blood, remove waste, and regulate fluid and electrolyte balance.

• Nephron: Functional unit of the kidney.

• Glomerular filtration rate (GFR): Rate at which blood is filtered.

• Equation: $\text{GFR} = \frac{\text{Urine Concentration} \times \text{Urine Flow Rate}}{\text{Plasma Concentration}}$

Chapter 20 – Fluid and Electrolyte Balance

Water and Electrolyte Homeostasis

Fluid balance is maintained by hormones and kidney function.

• Antidiuretic hormone (ADH): Promotes water reabsorption.

• Aldosterone: Promotes sodium reabsorption.

• Renin-angiotensin system: Regulates blood pressure and fluid balance.

Chapter 21 – The Digestive System

Digestive Tract Structure and Function

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

• Layers: Mucosa, submucosa, muscularis, serosa.

• Motility: Peristalsis and segmentation.

• Enzymes: Amylase, protease, lipase.

Chapter 22 – Endocrine Control of Growth and Metabolism

Hormones and Endocrine Glands

Endocrine glands secrete hormones that regulate growth, metabolism, and homeostasis.

• Thyroid hormones: Regulate metabolism.

• Adrenal hormones: Cortisol, aldosterone.

• Parathyroid hormone: Regulates calcium.

Chapter 24 – The Immune System

Innate and Adaptive Immunity

The immune system protects against pathogens through innate and adaptive mechanisms.

• Innate immunity: Non-specific, immediate response (skin, phagocytes).

• Adaptive immunity: Specific, memory-based response (B and T lymphocytes).

• Antibodies: Proteins that bind antigens.

• Inflammation: Response to injury or infection.

Cells and Molecules of Immunity

• B lymphocytes: Produce antibodies.

• T lymphocytes: Kill infected cells, regulate immune response.

• Major histocompatibility complex (MHC): Presents antigens to T cells.

Hypersensitivity and Autoimmunity

• Immediate hypersensitivity: Rapid allergic response.

• Delayed hypersensitivity: Slower, cell-mediated response.

• Autoimmunity: Immune response against self-tissues.

*Additional info: Academic context and definitions have been expanded for clarity and completeness.*