Introduction to Anatomy & Physiology

Key Terminology and Concepts

Anatomy and Physiology (A&P) is the study of the structure and function of the human body. Understanding basic terminology is essential for describing locations, positions, and relationships of body parts.

• Anatomical Position: The standard reference position for the body: standing upright, facing forward, arms at the sides, palms facing forward.

• Prone Position: Lying face down.

• Supine Position: Lying face up.

• Anterior (Ventral): Toward the front of the body.

• Posterior (Dorsal): Toward the back of the body.

• Superior: Above or toward the head.

• Inferior: Below or toward the feet.

• Proximal: Closer to the point of attachment or origin.

• Distal: Farther from the point of attachment or origin.

• Bilateral: On both sides of the body.

• Ipsilateral: On the same side of the body.

• Deep: Away from the surface of the body.

• Superficial: Near the surface of the body.

• Medial: Toward the midline of the body.

• Lateral: Away from the midline of the body.

Four Quadrants: The abdomen is divided into four quadrants (right upper, left upper, right lower, left lower) to help locate organs and describe pain or injury.

Negative Feedback

Negative feedback is a fundamental concept in physiology, describing how the body maintains homeostasis by reversing changes to return to a set point.

• Example: When body temperature rises, mechanisms such as sweating are activated to cool the body down.

Equation:

Tissues

Overview and Classification

Tissues are groups of cells with similar structure and function. The four basic types are epithelial, connective, muscle, and nervous tissue.

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

• Connective Tissue: Supports, protects, and binds other tissues.

• Muscle Tissue: Responsible for movement.

• Nervous Tissue: Transmits electrical impulses.

Important Vocabulary

• Tight Junctions: Seal cells together to prevent leakage.

• Desmosomes: Anchor cells together for structural integrity.

• Gap Junctions: Allow communication between cells.

• Endocytosis/Exocytosis: Processes for moving substances into/out of cells.

• Apical Surface: The exposed surface of epithelial cells.

• Basal Surface: The surface attached to the basement membrane.

• Basement Membrane: Thin layer anchoring epithelium to underlying tissue.

• Basal Lamina/Reticular Lamina: Layers of the basement membrane.

• Microvilli: Increase surface area for absorption.

• Cilia: Move substances across cell surfaces.

• Mucin: Protein component of mucus.

• Goblet Cell: Secretes mucus in epithelial tissue.

• Classification of Epithelial Tissue: Based on cell layers (simple, stratified) and cell shape (squamous, cuboidal, columnar).

Classification Table of Epithelial Tissue

Connective Tissue Vocabulary

• Extracellular Matrix: Non-cellular material surrounding cells, providing support.

• Ground Substance: Gel-like material in the matrix.

• Proteoglycans/Glycosaminoglycans: Molecules in the ground substance that attract water.

• Mesenchymal Cells: Embryonic cells that give rise to connective tissue.

• Serous Membrane: Lines body cavities, secretes serous fluid.

• Adipocytes: Fat cells.

• Macrophages: Immune cells that engulf debris.

• Fibroblasts: Cells that produce fibers and ground substance.

• Elastic Fibers/Collagen Fibers: Provide elasticity and strength.

• Types of Connective Tissue: Loose (areolar, adipose), dense (regular, irregular), cartilage, bone, blood.

Connective Tissue Table

Plasma Membrane Proteins

• Functions: Transport, cell recognition, enzymatic activity, signal transduction, intercellular joining, attachment to cytoskeleton and extracellular matrix.

Skin (Integumentary System)

Structure and Function

The skin is the largest organ of the body, providing protection, sensation, and regulation of temperature.

• Epidermis: Outermost layer, composed of stratified squamous epithelium.

• Dermis: Middle layer, contains connective tissue, blood vessels, nerves.

• Subcutaneous Tissue (Hypodermis): Deepest layer, contains adipose tissue.

Important Vocabulary

• Striae: Stretch marks.

• Keratinocyte: Main cell type in epidermis, produces keratin.

• Melanocyte: Produces melanin pigment.

• Papillary Dermis: Upper layer of dermis, forms fingerprints.

• Lamellar Corpuscle: Sensory receptor for pressure.

• Flexure Lines: Skin folds at joints.

• Cleavage Lines: Natural orientation of collagen fibers.

• Apocrine/Eccrine Sweat Glands: Types of sweat glands; apocrine in axillary/genital areas, eccrine all over body.

• Sebaceous Glands: Secrete sebum (oil).

• Hair Follicle: Structure from which hair grows.

• Keratin: Protein providing strength and waterproofing.

• Sebum: Oily secretion.

• Integumentary System: Includes skin, hair, nails, glands.

Burns

• 1st Degree Burn: Affects only the epidermis; redness, pain.

• 2nd Degree Burn: Affects epidermis and part of dermis; blisters.

• 3rd Degree Burn: Destroys both epidermis and dermis; may affect deeper tissues.

Skin Cancer Types

• Basal Cell Carcinoma: Most common, least dangerous; arises from basal cells.

• Squamous Cell Carcinoma: Arises from squamous cells; can metastasize.

• Melanoma: Most dangerous; arises from melanocytes.

Functions of Skin

• Protection against pathogens and injury

• Regulation of body temperature

• Sensation (touch, pain, temperature)

• Excretion of wastes

• Synthesis of vitamin D

Homeostasis and Skin

• Temperature Regulation: Sweat glands and blood vessels help maintain body temperature.

• Cold Response: Blood vessels constrict, shivering increases heat production.

• Hot Response: Blood vessels dilate, sweating increases heat loss.

Additional Info

• Endocrine vs. Exocrine Glands: Endocrine glands secrete hormones directly into the bloodstream; exocrine glands secrete substances into ducts leading to body surfaces or cavities.

• Parietal vs. Visceral Layers: Parietal layer lines the cavity; visceral layer covers the organ.

Additional info: Some definitions and examples have been expanded for clarity and completeness.