Introduction to Anatomy and Physiology

Definitions and Relationship

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

• Physiology is the study of the function of the body’s structural machinery—how the body parts work and carry out their life-sustaining activities.

• The two fields are closely related: structure determines function, and function reflects structure.

• Example: The thin walls of alveoli in the lungs (anatomy) allow for efficient gas exchange (physiology).

Levels of Organization

From Atom to Organism

• Chemical Level: Atoms combine to form molecules.

• Cellular Level: Cells are made up of molecules.

• Tissue Level: Tissues consist of similar types of cells.

• Organ Level: Organs are made up of different types of tissues.

• Organ System Level: Organ systems consist of different organs that work together closely.

• Organismal Level: The human organism is made up of many organ systems.

Homeostasis

Definition and Mechanisms

• Homeostasis is the maintenance of a stable internal environment despite changes in the external environment.

• Key components: Receptor (detects change), Control Center (processes information), Effector (carries out response).

• Example: Regulation of body temperature—thermoreceptors (receptors) send signals to the hypothalamus (control center), which activates sweat glands (effectors).

Feedback Systems

• Negative Feedback: The response reduces or shuts off the original stimulus. Example: Blood glucose regulation by insulin.

• Positive Feedback: The response enhances the original stimulus. Example: Blood clotting, labor contractions.

Medical Terminology

Roots, Prefixes, and Suffixes

• Root: Basic, meaningful part of a term (e.g., cardi = heart).

• Prefix: Added to the beginning of a word to modify its meaning (e.g., hyper- = above normal).

• Suffix: Added to the end of a word to form another term (e.g., -itis = inflammation).

Planes of Reference and Anatomical Terms

Body Planes

• Coronal (Frontal) Plane: Divides the body into anterior and posterior parts.

• Sagittal Plane: Divides the body into right and left parts; midsagittal is exactly in the midline.

• Transverse Plane: Divides the body into superior and inferior parts.

Anatomical Position and Directional Terms

• Anatomical Position: Body erect, feet slightly apart, palms facing forward, thumbs pointing away from the body.

• Superior (Cranial): Toward the head.

• Inferior (Caudal): Away from the head.

• Anterior (Ventral): Toward the front.

• Posterior (Dorsal): Toward the back.

• Medial: Toward the midline.

• Lateral: Away from the midline.

• Proximal: Closer to the origin of the body part.

• Distal: Farther from the origin.

• Superficial: Toward or at the body surface.

• Deep: Away from the body surface.

Major Body Systems and Functions

• Integumentary: Protection, temperature regulation, sensation.

• Skeletal: Support, protection, movement, blood cell production.

• Muscular: Movement, posture, heat production.

• Cardiovascular: Transport of nutrients, gases, wastes.

• Respiratory: Gas exchange.

• Lymphatic: Immunity, fluid balance.

• Digestive: Breakdown and absorption of nutrients.

• Nervous: Control, communication, response to stimuli.

• Endocrine: Hormone production, regulation of body processes.

• Urinary: Waste elimination, water balance.

• Reproductive: Production of offspring.

Body Cavities and Abdominopelvic Regions

• Dorsal Cavity: Contains the cranial and vertebral cavities.

• Ventral Cavity: Contains the thoracic and abdominopelvic cavities.

• Abdominopelvic Quadrants: Right Upper, Left Upper, Right Lower, Left Lower.

• Abdominopelvic Regions: Right/Left hypochondriac, epigastric, right/left lumbar, umbilical, right/left iliac, hypogastric.

Organic Molecules

Types, Functions, and Monomers

• Carbohydrates: Main energy source; monomer = monosaccharide.

• Lipids: Energy storage, insulation, cell membranes; monomer = fatty acids and glycerol.

• Proteins: Structure, enzymes, transport; monomer = amino acids.

• Nucleic Acids: Genetic information; monomer = nucleotide.

Plasma Membrane Movements

Types of Transport

• Isotonic: Equal solute concentration; no net water movement.

• Hypotonic: Lower solute concentration outside; water enters cell.

• Hypertonic: Higher solute concentration outside; water leaves cell.

• Passive Transport: No energy required.

  • Diffusion: Movement from high to low concentration.

  • Osmosis: Diffusion of water across a membrane.

  • Facilitated Diffusion: Uses carrier proteins.

• Active Transport: Requires energy (ATP).

  • Pumps: Move substances against gradient.

  • Endocytosis: Intake of materials (phagocytosis = solids, pinocytosis = liquids).

  • Exocytosis: Expulsion of materials.

  • Cotransport: Coupled transport of two substances.

Cell Components

Structure and Function

• Plasma Membrane: Selective barrier; regulates entry/exit.

• Nucleus: Contains genetic material (DNA).

• Cytoplasm: Fluid and organelles between membrane and nucleus.

• Endoplasmic Reticulum (ER): Synthesis of proteins (rough ER) and lipids (smooth ER).

• Golgi Apparatus: Modifies, sorts, and packages proteins/lipids.

• Ribosome: Protein synthesis.

• Lysosome: Digestion of cellular waste.

• Mitochondria: ATP production (cellular respiration).

• Flagella and Cilia: Movement of cell or substances.

• Microfilaments: Cell shape and movement.

Tissues

Major Types, Structure, and Function

• Epithelial Tissue: Covers surfaces, lines cavities, forms glands.

  • Cell junctions: tight, gap, adhesion.

  • Shapes: squamous, cuboidal, columnar (simple & stratified), pseudostratified.

  • Glands: merocrine, apocrine, holocrine.

• Connective Tissue: Supports, binds, protects.

  • Loose: areolar, adipose, reticular.

  • Dense: regular, irregular, elastic.

  • Others: cartilage (hyaline, elastic, fibrous), bone (spongy, compact), blood (RBC, WBC, plasma).

• Muscular Tissue: Movement.

  • Types: skeletal, smooth, cardiac.

• Nervous Tissue: Communication.

  • Neurons: dendrites, cell body, axon.

  • Neuroglia: support cells.

Connective Tissue Proper

Components and Functions

• Cells: Fibroblast, mast cell, macrophage, microphages, lymphocytes, adipocytes, mesenchyme/stem cells, melanocytes.

• Fibers: Collagen (strength), elastic (flexibility), reticular (support).

• Ground Substance: Fills space between cells and fibers.

• Matrix: Combination of fibers and ground substance.

Membranes and Fascia

Types and Functions

• Mucous Membranes: Line cavities open to exterior; secrete mucus.

• Serous Membranes: Line closed cavities; secrete serous fluid.

• Cutaneous Membrane: Skin; protection.

• Synovial Membranes: Line joint cavities; secrete synovial fluid.

• Fascia: Connective tissue layers—superficial, deep, subserous.

Integumentary System

Functions

• Protection, temperature regulation, sensation, vitamin D synthesis, excretion.

Skin Structure

• Epidermis: Stratified squamous epithelium.

  • Layers (from superficial to deep): stratum corneum, stratum lucidum (only in thick skin), stratum granulosum, stratum spinosum (mucosum), stratum basale (germinativum).

• Dermis: Connective tissue.

  • Papillary region (dermal papillae), reticular region.

• Hypodermis: Adipose tissue; anchors skin to underlying structures.

Accessory Organs of the Skin

• Hair: Types (vellus, terminal); anatomy (shaft, root, follicle, bulb).

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

• Arrector Pili Muscles: Cause hair to stand up (goosebumps).

• Nails: Body, bed, groove, fold, hyponychium, eponychium, lunula.

Skin Pigments and Substances

• Sebum: Oily secretion from sebaceous glands; lubricates skin and hair.

• Sweat: Produced by sweat glands; aids in temperature regulation.

• Melanin: Pigment produced by melanocytes; protects against UV radiation.

• Keratin: Protein that strengthens skin, hair, and nails.

• Pigments: Carotene (yellow-orange), melanin (pheomelanin = red-yellow, eumelanin = brown-black).

Vitamin D3 Synthesis

• Location: Synthesized in the skin when exposed to UV light.

• Function: Needed for calcium absorption and bone health.

Additional info: Students should also be familiar with diseases/disorders of all systems, as indicated in the objectives.