Anatomy & Physiology Study Guide: Intro, Histology, Integumentary, and Nervous System

Introduction to Anatomy & Physiology

Overview of Anatomy and Physiology

Anatomy and physiology are foundational sciences in understanding the structure and function of the human body. Anatomy focuses on the physical structures, while physiology examines how those structures work.

• Anatomy: The study of body structure, including organs, tissues, and cells.

• Physiology: The study of body function, describing how anatomical structures operate. L

• Types of Anatomy:

  • Gross anatomy (macroscopic)

  • Microscopic anatomy (histology)

  • Surface anatomy

• Examples: Studying the heart's chambers (anatomy) vs. understanding how the heart pumps blood (physiology).

Anatomical Position and Terminology

Standardized anatomical terms allow precise communication about body locations and directions.

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

• Directional Terms:

  • Superior (above)

  • Inferior (below)

  • Anterior (front)

  • Posterior (back)

  • Medial (toward midline)

  • Lateral (away from midline)

  • Proximal (closer to origin)

  • Distal (farther from origin)

  • Superficial (toward surface) '

  • Deep (away from surface)

Body Cavities and Membranes

The body contains several cavities that house organs, each lined by membranes.

• Dorsal cavity: Contains the brain and spinal cord.

• Ventral cavity: Contains thoracic and abdominopelvic cavities.

• Serous Membranes: Thin membranes lining body cavities; include parietal (lining cavity wall) and visceral (covering organs) layers.

• Examples: Pleura (lungs), pericardium (heart), peritoneum (abdominal organs).

Abdominal Quadrants

The abdomen is divided into four quadrants for clinical reference.

• Right Upper Quadrant (RUQ): Liver, gallbladder

• Left Upper Quadrant (LUQ): Stomach, spleen

• Right Lower Quadrant (RLQ): Appendix, cecum

• Left Lower Quadrant (LLQ): Descending colon, sigmoid colon

Histology /

Overview of Tissues

Tissues are groups of similar cells performing a common function. There are four major tissue types in the body.

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

• Connective tissue: Supports, protects, binds other tissues.

• Muscle tissue: Produces movement.

• Nervous tissue: Transmits electrical signals.

General Characteristics and Functions of Epithelial Tissue

• Characteristics: Closely packed cells, polarity, avascular, high regeneration.

• Functions: Protection, absorption, filtration, secretion.

Types of Epithelial Tissue

Each type of epithelial tissue has distinct characteristics, functions, and locations.

• Simple squamous: Single layer, flat cells; found in alveoli, blood vessels; allows diffusion.

• Simple cuboidal: Single layer, cube-shaped; found in kidney tubules; secretion/absorption.

• Simple columnar: Single layer, tall cells; found in digestive tract; absorption/secretion.

• Pseudostratified columnar: Appears layered, but all cells touch basement membrane; found in respiratory tract.

• Stratified squamous: Multiple layers, flat cells; found in skin, mouth; protection.

• Stratified cuboidal/columnar: Rare; found in ducts of glands.

• Transitional: Changes shape; found in urinary bladder.

Cell Junctions

• Tight junctions: Prevent leakage between cells.

• Desmosomes: Anchor cells together.

• Gap junctions: Allow communication between cells.

Connective Tissue

Connective tissue supports and connects other tissues. It consists of cells, fibers, and ground substance.

• Cells: Fibroblasts, chondroblasts, adipocytes, etc.

• Fibers: Collagen, elastic, reticular.

• Ground substance: Gel-like material between cells and fibers.

Type	Characteristics	Location
Loose CT (areolar)	Gel-like, many cell types	Under epithelia
Adipose	Fat storage	Subcutaneous tissue
Dense regular	Parallel collagen fibers	Tendons, ligaments
Dense irregular	Irregular collagen fibers	Dermis of skin
Cartilage (hyaline, fibrocartilage, elastic)	Firm, flexible	Joints, ear, nose

Integumentary System

Overview and Functions

The integumentary system includes the skin, hair, nails, and glands. It protects the body, regulates temperature, a

nd provides sensory information.

• Organs: Skin, hair, nails, sweat glands, sebaceous glands.

• Functions: Protection, sensation, thermoregulation, vitamin D synthesis.

Layers of the Skin

• Epidermis: Outer layer; contains keratinocytes, melanocytes.

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

• Hypodermis (subcutaneous): Deepest layer; contains adipose tissue.

Epidermal Layers

• Stratum basale

• Stratum spinosum

• Stratum granulosum

• Stratum lucidum (only in thick skin)

• Stratum corneum

Skin Color and Markings

• Pigments: Melanin, carotene, hemoglobin.

• Markings: Nevus (mole), hemangioma, friction ridges.

Glands and Hair

• Sudoriferous glands: Sweat production.

• Sebaceous glands: Oil production.

• Hair: Protection, sensation.

Burns and Skin Cancer

• Rule of Nines: Used to estimate burn area.

• Burn Degrees:

  • 1st degree: Epidermis only

  • 2nd degree: Epidermis and part of dermis

  • 3rd degree: Full thickness

• Skin Cancer Types: Basal cell carcinoma, squamous cell carcinoma, melanoma.

Nervous System

Overview and Organization

The nervous system controls and coordinates body activities. It is divided into the central nervous system (CNS) and peripheral nervous system (PNS).

• CNS: Brain and spinal cord.

• PNS: Nerves outside the CNS.

• Functional Divisions: Sensory (afferent), motor (efferent), integration.

Cells of the Nervous System

• Neurons: Transmit electrical signals.

  • Cell body (soma)

  • Dendrites

  • Axon (with axon hillock, collaterals, synaptic knobs)

• Neuroglia (glial cells): Support neurons.

  • Astrocytes

  • Microglial cells

  • Ependymal cells

  • Oligodendrocytes (CNS)

  • Schwann cells (PNS)

  • Satellite cells (PNS)

Nerve Structure

• Connective tissue coverings:

  • Endoneurium (around each axon)

  • Perineurium (around fascicles)

  • Epineurium (around entire nerve)

Synapses and Circuits

• Synapse: Junction between neurons; allows communication.

• Types of Circuits:

  • Converging

  • Diverging

  • Reverberating

  • Parallel after-discharge

Nervous System: Action Potentials

Action Potentials

Action potentials are rapid changes in membrane potential that allow neurons to transmit signals.

• Resting membrane potential: The voltage across the membrane at rest, typically -70 mV.

• Depolarization: Na+ influx causes membrane potential to become more positive.

• Repolarization: K+ efflux restores negative membrane potential.

• Hyperpolarization: Membrane potential becomes more negative than resting.

• Absolute refractory period: No new action potential can be initiated.

• Relative refractory period: Stronger stimulus required for new action potential.

• Saltatory conduction: Action potentials "jump" between nodes of Ranvier in myelinated axons, increasing speed.

Key Equations

• Nernst Equation: Calculates equilibrium potential for an ion: $E = \frac{RT}{zF} \ln \frac{[\text{ion outside}]}{[\text{ion inside}]}$

• Ohm's Law (for membrane): $I = g(V_m - E_{ion})$

Graphical Representation

• Action potentials can be graphed as changes in membrane voltage over time, showing phases of depolarization, repolarization, and hyperpolarization.

Synaptic Transmission

• Chemical synapses: Use neurotransmitters to transmit signals.

• Electrical synapses: Use gap junctions for direct ion flow.

Neuronal Pools and Circuits

Type	Description	Example
Converging	Many inputs, one output	Vision
Diverging	One input, many outputs	Motor pathways
Reverberating	Feedback loop	Breathing rhythm
Parallel after-discharge	Inputs diverge, then reconverge	Complex reflexes

Additional info: These notes expand on the outline provided, adding definitions, examples, and academic context for clarity and completeness.