Introduction to Anatomy & Physiology

Overview of Anatomy and Physiology

Anatomy is the study of the structure of body parts, while physiology focuses on their functions. Together, these disciplines provide a comprehensive understanding of the human body.

• Anatomy: Examines the form and organization of body structures.

• Physiology: Explores how body parts work and carry out life-sustaining activities.

Organization of the Human Body

• Levels of Organization: Chemical → Cellular → Tissue → Organ → Organ System → Organism

Characteristics of Living Things

• Organization

• Metabolism

• Growth and development

• Responsiveness

• Regulation

• Reproduction

Homeostasis

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

• Negative Feedback: Reverses a change to maintain balance (e.g., body temperature regulation).

• Positive Feedback: Enhances a change (e.g., blood clotting, labor contractions).

Anatomical Position and Terminology

• Anatomical Position: Body upright, facing forward, arms at sides, palms forward.

• Directional Terms: Superior/inferior, anterior/posterior, medial/lateral, proximal/distal, superficial/deep.

• Body Planes: Sagittal, frontal (coronal), transverse (horizontal).

• Body Cavities: Dorsal (cranial, vertebral), ventral (thoracic, abdominopelvic).

• Abdominopelvic Regions (9): Right/left hypochondriac, epigastric, right/left lumbar, umbilical, right/left iliac, hypogastric.

• Abdominopelvic Quadrants (4): Right upper, left upper, right lower, left lower.

• Serous Membranes: Line body cavities; include parietal and visceral layers (e.g., pleura, pericardium, peritoneum).

Cell Chemistry & Cell Components

Basic Chemistry Concepts

• Matter: Anything that occupies space and has mass; exists as solids, liquids, or gases.

• Elements: Pure substances; major biological elements include CHNOPS (Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur).

• Atoms: Smallest unit of an element; composed of protons, neutrons, electrons.

• Atomic Number: Number of protons in the nucleus.

• Atomic Mass: Sum of protons and neutrons.

• Valence Electrons: Electrons in the outermost shell; determine chemical reactivity.

Chemical Bonds and Water

• Ions: Charged atoms; cations (+), anions (−).

• Bond Types:

  • Ionic Bonds: Transfer of electrons.

  • Covalent Bonds: Sharing of electrons (polar: unequal sharing; nonpolar: equal sharing).

  • Hydrogen Bonds: Weak attractions between polar molecules (important in water, DNA).

• Properties of Water: Cohesion, adhesion, high heat capacity, solvent abilities.

Chemical Reactions and Enzymes

• Reactants → Products

• Types of Reactions: Synthesis, decomposition, exchange.

• Activation Energy: Minimum energy required for a reaction to occur.

• Enzymes: Biological catalysts that lower activation energy.

Macromolecules

• Carbohydrates: Monomer: monosaccharides (e.g., glucose).

• Lipids: Monomer: fatty acids and glycerol (e.g., triglycerides).

• Proteins: Monomer: amino acids (e.g., enzymes, hemoglobin).

• Nucleic Acids: Monomer: nucleotides (e.g., DNA, RNA).

Acids, Bases, and pH

• Acids: Release H+ ions; pH < 7.

• Bases: Accept H+ ions; pH > 7.

• Buffers: Resist changes in pH.

ATP and DNA Structure

• ATP (Adenosine Triphosphate): Main energy currency of the cell.

• DNA Structure: Double helix composed of nucleotides (A, T, C, G).

Energy & Cell Processes

Cell Theory and Types

• Cell Theory: All living things are composed of cells; cells are the basic unit of life; all cells arise from pre-existing cells.

• Prokaryotes vs. Eukaryotes: Prokaryotes lack a nucleus; eukaryotes have a nucleus and membrane-bound organelles.

Animal Cell Structure

• Organelles: Nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, cytoskeleton.

• Plasma Membrane: Phospholipid bilayer with embedded proteins; regulates entry/exit of substances.

Membrane Transport

• Passive Transport: No energy required; includes diffusion, facilitated diffusion, osmosis.

• Active Transport: Requires energy (ATP); includes primary/secondary transport, endocytosis (phagocytosis, pinocytosis), exocytosis.

• Concentration Gradients: Difference in concentration across a membrane.

• Tonicity: Hypotonic (cell swells), hypertonic (cell shrinks), isotonic (no net change).

Protein Synthesis

• Transcription: DNA → mRNA in the nucleus.

• RNA Processing: Modification of pre-mRNA (splicing, capping, polyadenylation).

• Translation: mRNA → protein at the ribosome.

• mRNA: Carries genetic code from DNA to ribosome.

Cell Cycle and Mitosis

• Stages: Interphase (G1, S, G2), Mitosis (prophase, metaphase, anaphase, telophase), Cytokinesis.

• Purpose: Growth, repair, asexual reproduction.

Tissues & Histology

Four Primary Tissue Types

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

• Connective Tissue: Supports, binds, protects organs.

• Muscle Tissue: Produces movement.

• Nervous Tissue: Conducts electrical impulses.

Epithelial Tissue

• Classification: By layers (simple, stratified) and shape (squamous, cuboidal, columnar, transitional).

• Microscope Identification: Simple cuboidal, stratified cuboidal, simple squamous, stratified squamous, simple columnar, transitional.

• Cell Junctions: Tight junctions, desmosomes, gap junctions.

• Glandular Epithelium: Endocrine (ductless, secrete hormones), exocrine (ducts, secrete onto surfaces).

• Locations/Functions: Vary by type; e.g., simple squamous in alveoli, stratified squamous in skin.

Connective Tissue (CT)

• Four Classes: Connective tissue proper, cartilage, bone, blood.

• Functions: Support, protection, transport, storage.

• Fibers: Collagen, elastic, reticular.

• ECM Components: Fibers and ground substance.

• Types and Examples:

  • Loose CT: Areolar, adipose, reticular

  • Dense CT: Dense regular (tendons)

  • Bone CT: Compact bone (osteon)

  • Cartilage CT: Hyaline, fibrous, elastic

  • Fluid CT: Blood

Muscle Tissue

• Types: Skeletal (voluntary, striated), cardiac (involuntary, striated, intercalated discs), smooth (involuntary, non-striated).

• Functions/Locations: Movement, posture, heat production; found in muscles, heart, walls of hollow organs.

Nervous Tissue

• Neurons: Conduct impulses.

• Neuroglia: Support and protect neurons.

Body Membranes

• Epithelial Membranes: Serous (line cavities), mucous (line passages open to exterior), cutaneous (skin).

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

Integumentary System

Structure and Function

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

Layers of the Skin

• Epidermis: Five layers (from deep to superficial):

  1. Stratum basale

  2. Stratum spinosum

  3. Stratum granulosum

  4. Stratum lucidum (only in thick skin)

  5. Stratum corneum

• Dermis: Two layers:

  • Papillary layer (areolar CT)

  • Reticular layer (dense irregular CT)

• Hypodermis: Subcutaneous layer; mostly adipose tissue.

Specialized Cells and Structures

• Cells: Keratinocytes, melanocytes, Langerhans cells, Merkel cells.

• Hair/Follicle: Protection, sensation; structure includes shaft, root, follicle.

• Nails: Protect distal digits.

• Glands:

  • Sebaceous (oil)

  • Sweat (sudoriferous): eccrine and apocrine

  • Ceruminous (earwax)

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

Clinical Aspects

• Rule of 9s: Used to estimate body surface area affected by burns.

• Burns: Classified by depth (first, second, third degree); affect skin layers and function.

• Skin Cancer: Criteria for assessment include asymmetry, border, color, diameter, evolving (ABCDE rule).

• Wound Healing: Involves inflammation, proliferation, remodeling.

Developmental Changes

• Skin structure and function change with age (e.g., thinning, decreased elasticity, reduced gland activity).

Example: The skin (integumentary system) protects against pathogens, prevents water loss, and helps regulate body temperature through sweat glands and blood flow adjustments.

Additional info: Some details (e.g., specific microscope slide identification, all possible tissue locations) are inferred as standard for introductory A&P courses.