Introduction to Anatomy and Physiology

Definitions and Scope

• Anatomy: The study of the structure of body parts and their relationships to one another.

• Physiology: The study of the function of the body’s structural machinery.

• Gross Anatomy: Study of large, visible structures (e.g., organs, muscles).

• Microscopic Anatomy: Study of structures too small to be seen with the naked eye, including cytology (cells) and histology (tissues).

Characteristics of Living Things

• Organization

• Metabolism

• Growth and development

• Responsiveness to stimuli

• Regulation (homeostasis)

• Reproduction

Levels of Organization

• Chemical level (atoms, molecules)

• Cellular level (cells)

• Tissue level (groups of similar cells)

• Organ level (two or more tissue types)

• Organ system level (organs working together)

• Organismal level (the whole organism)

Body Systems and Functions

• Integumentary: Protection, temperature regulation

• Skeletal: Support, protection, blood cell production

• Muscular: Movement, heat production

• Nervous: Control, communication

• Endocrine: Hormone production, regulation

• Cardiovascular: Transport of nutrients and gases

• Lymphatic: Immunity, fluid balance

• Respiratory: Gas exchange

• Digestive: Nutrient breakdown and absorption

• Urinary: Waste elimination, water balance

• Reproductive: Production of offspring

Anatomical Position and Terminology

• Standard anatomical position: standing upright, facing forward, arms at sides, palms forward, feet flat and parallel.

• Directional terms: anterior/posterior, superior/inferior, medial/lateral, proximal/distal, superficial/deep.

• Body regions: e.g., cephalic (head), thoracic (chest), abdominal, pelvic, etc.

Anatomical Planes and Cavities

• Planes: Sagittal (left/right), Frontal (anterior/posterior), Transverse (superior/inferior).

• Body cavities: Dorsal (cranial, vertebral), Ventral (thoracic, abdominopelvic).

• Main organs in each cavity: e.g., brain in cranial, lungs in thoracic, digestive organs in abdominopelvic.

• Abdominopelvic quadrants (RUQ, LUQ, RLQ, LLQ) and nine regions (e.g., epigastric, umbilical).

Serous Membranes

• Layers: parietal (lines cavity), visceral (covers organ), serous fluid in between.

• Main types: pleura (lungs), pericardium (heart), peritoneum (abdominal organs).

Homeostasis and Feedback

• Homeostasis: Maintenance of a stable internal environment.

• Feedback loop components: stimulus, receptor, control center, effector, response.

• Negative feedback: reverses change (e.g., body temperature regulation).

• Positive feedback: amplifies change (e.g., blood clotting).

Gradients and Cell Communication

• Gradient: Difference in concentration, pressure, or electrical charge between two regions.

• Examples: concentration gradient, pressure gradient, electrical gradient.

• Cell communication: chemical signaling (hormones, neurotransmitters), electrical signaling.

Metabolism and Nutrition

Metabolic Processes

• Metabolism: All chemical reactions in the body.

• Anabolism: Building complex molecules from simpler ones (requires energy).

• Catabolism: Breaking down complex molecules into simpler ones (releases energy).

Nutrient Monomers and ATP Synthesis

• Three main nutrient monomers: glucose (carbohydrates), fatty acids (lipids), amino acids (proteins).

• ATP (adenosine triphosphate) is the main energy currency of the cell.

Energy Coupling and ATP Hydrolysis

• Exergonic reactions release energy; endergonic reactions require energy.

• Cells couple exergonic and endergonic reactions to drive cellular processes.

• ATP hydrolysis is highly exergonic:

Redox Reactions and Electron Carriers

• Oxidation: Loss of electrons.

• Reduction: Gain of electrons.

• Electromotive force: The force that drives electron flow.

• Electron carriers: NAD+ and FAD (in cytosol and mitochondria).

ATP Generation Pathways

• Substrate-level phosphorylation: Direct transfer of phosphate to ADP.

• Oxidative phosphorylation: Uses electron transport chain and chemiosmosis.

Glucose Catabolism Overview

• Glycolysis: Occurs in cytosol; glucose → 2 pyruvate, 2 ATP, 2 NADH.

• Intermediate step: Pyruvate → Acetyl-CoA (aerobic) or lactate (anaerobic).

• Citric Acid Cycle: Acetyl-CoA → CO2, NADH, FADH2, 2 ATP per glucose.

• Electron Transport Chain: NADH/FADH2 donate electrons, ATP produced via oxidative phosphorylation.

• Role of oxygen: final electron acceptor in ETC.

• Overall aerobic glucose catabolism:

Histology

Tissues and Their Classification

• Tissue: Group of similar cells performing a common function.

• Four main types: epithelial, connective, muscle, nervous.

Extracellular Matrix (ECM)

• Two major components: ground substance and protein fibers.

• Three fiber types: collagen (strength), elastic (flexibility), reticular (support).

• Ground substance contains water, glycosaminoglycans, proteoglycans, glycoproteins.

Cell Junctions

• Tight junctions: Prevent leakage (e.g., intestines).

• Desmosomes: Provide mechanical strength (e.g., skin).

• Gap junctions: Allow communication (e.g., cardiac muscle).

Epithelial Tissue

• Main characteristics: cellularity, polarity, avascularity, regeneration.

• Functions: protection, absorption, filtration, secretion, sensation.

• Classified by layers: simple (one layer), stratified (multiple layers).

• Classified by shape: squamous (flat), cuboidal (cube), columnar (tall).

• Examples: simple squamous (alveoli), stratified squamous (skin), simple cuboidal (kidney tubules), simple columnar (intestine).

• Ciliated vs. nonciliated: cilia move substances; keratinized vs. nonkeratinized: keratin adds protection.

Glands and Secretions

• Exocrine glands: Secrete via ducts (e.g., sweat, salivary glands).

• Endocrine glands: Secrete hormones into blood.

• Goblet cells: Unicellular glands producing mucus.

• Modes of secretion: merocrine (exocytosis), apocrine (part of cell), holocrine (whole cell ruptures).

Connective Tissue

• Basic components: cells, fibers, ground substance.

• Functions: support, protection, transport, energy storage.

• Cell types: fibroblasts, adipocytes, macrophages, mast cells.

• Types: areolar, dense regular/irregular/elastic, reticular, adipose, cartilage (hyaline, elastic, fibrocartilage), bone, blood.

Muscle and Nervous Tissue

• Muscle types: skeletal (voluntary, striated), cardiac (involuntary, striated, intercalated discs), smooth (involuntary, non-striated).

• Nervous tissue: neurons (signal transmission), neuroglia (support).

Body Membranes and Tissue Repair

• Membranes: mucous, serous, cutaneous, synovial.

• Tissue repair: regeneration (restores function), fibrosis (scar tissue formation).

Integumentary System

Skin Structure and Function

• Terms: hypertrophy (cell size increase), hyperplasia (cell number increase), atrophy (cell size/number decrease), dysplasia (abnormal growth), neoplasia (uncontrolled growth).

• Layers: epidermis (outer), dermis (middle), hypodermis (below dermis).

• Hypodermis: adipose tissue, anchors skin, insulates.

• Functions: protection, sensation, thermoregulation, excretion, vitamin D synthesis.

Epidermis and Dermis

• Five layers of epidermis (deep to superficial): stratum basale, spinosum, granulosum, lucidum (thick skin only), corneum.

• Keratinocytes: main cell, produce keratin, undergo lifecycle from basal to corneum.

• Other cells: melanocytes (pigment), Merkel cells (touch), Langerhans cells (immune).

• Thick skin (palms, soles): five layers; thin skin: four layers.

• Dermis: papillary (upper, loose CT), reticular (lower, dense CT).

Skin Features and Color

• Friction ridges: fingerprints, grip enhancement, individual identification.

• Cleavage lines: collagen fiber orientation, important for surgical incisions.

• Pigments: melanin (brown/black), carotene (yellow/orange), hemoglobin (red).

• Melanin: produced by melanocytes, protects against UV.

• Erythema: redness due to increased blood flow; skin aids in thermoregulation.

Hair, Nails, and Glands

• Hair: structure (shaft, root, follicle), types (lanugo, vellus, terminal), functions (protection, sensation).

• Nails: keratinized plates, growth from nail matrix.

• Glands: sweat (merocrine/eccrine, apocrine), sebaceous (oil).

• Merocrine: watery sweat, all over body; apocrine: thicker secretion, axillary/genital regions.

Skin Disorders and Burns

• Burns: first-degree (epidermis), second-degree (dermis), third-degree (full thickness).

• Rule of nines: estimates burn surface area.

• Skin cancers: squamous cell carcinoma, basal cell carcinoma, malignant melanoma (most dangerous).

Additional info: These notes expand on the learning objectives by providing definitions, examples, and context for each major topic. For exam preparation, students should be able to apply these concepts to case studies, diagrams, and clinical scenarios.