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

Module 1: Introduction to Anatomy & Physiology

Overview of Anatomy & Physiology

Anatomy and Physiology (A&P) is the study of the structure and function of the human body. Understanding the organization and processes of the body is foundational for all health sciences.

• Anatomy: The study of body structure, including the relationships among body parts.

• Physiology: The study of body function, focusing on how the body parts work together.

• Levels of Structural Organization: Six levels: chemical, cellular, tissue, organ, organ system, organism.

• Organ Systems: There are 11 major organ systems (e.g., integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, reproductive).

• Approaches to Studying Anatomy: Systemic (by organ system) vs. regional (by body region).

Language of Anatomy & Physiology

Precise terminology is essential for describing locations and relationships in the body.

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

• Directional Terms: Examples include superior/inferior, anterior/posterior, medial/lateral, proximal/distal.

• Regional Terms: Specific areas of the body (e.g., brachial for arm, femoral for thigh).

• Planes of Section: Sagittal (left/right), frontal (anterior/posterior), transverse (superior/inferior).

Organization of the Body

The body is organized into cavities and regions that help compartmentalize functions and structures.

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

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

• Serous Membranes: Thin membranes lining body cavities (pleura, pericardium, peritoneum).

• Naming Serous Membranes: Parietal (lines cavity wall) vs. visceral (covers organ).

Core Principles in A&P

Homeostasis and feedback mechanisms are central to maintaining internal stability.

• Homeostasis: The maintenance of a stable internal environment.

• Homeostatic Loop Components: Receptor, control center, effector.

• Feedback Loops: Negative feedback (reduces change, e.g., body temperature regulation) vs. positive feedback (amplifies change, e.g., childbirth).

• Gradient: A difference in concentration, pressure, or electrical charge between two regions (e.g., sodium gradient across a cell membrane).

Module 2: Histology (Tissues)

Overview of Tissues

Tissues are groups of cells with similar structure and function. The extracellular matrix (ECM) provides structural and biochemical support.

• Basic Components of Tissues: Cells and ECM.

• Basic Components of ECM: Ground substance and protein fibers.

• Main Tissue Types: Epithelial, connective, muscle, nervous.

• Protein Fiber Types: Collagen (strength), elastic (stretch), reticular (support).

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

• Specialization: Each tissue type has specialized cells and functions.

Epithelial Tissue

Epithelial tissue covers surfaces, lines cavities, and forms glands. It is classified by cell shape and layers.

• Naming Scheme: Simple (one layer) vs. stratified (multiple layers); squamous, cuboidal, columnar.

• Specialized Features: Microvilli (absorption), cilia (movement).

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

• Exocrine Glands: Secrete products into ducts; modes include merocrine, apocrine, holocrine.

Connective Tissue

Connective tissue supports, binds, and protects organs. It is characterized by diverse cell types and abundant ECM.

• Main Types: Connective tissue proper, specialized connective tissue.

• Connective Tissue Proper:

  • Loose connective tissue

  • Dense connective tissue (irregular, regular, elastic)

  • Reticular tissue

  • Adipose tissue

• Specialized Connective Tissue:

  • Cartilage (hyaline, fibrocartilage, elastic)

  • Bone

  • Blood

• Defining Features: Cell types (fibroblasts, chondrocytes, osteocytes, etc.), protein fibers, and special features (e.g., fat storage in adipose tissue).

Muscle Tissue

Muscle tissue is responsible for movement and force generation.

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

• Features: Cell shape, nuclei number, control type, special cell linkages.

Nervous Tissue

Nervous tissue transmits electrical signals for communication and control.

• Major Cell Types: Neurons and neuroglia.

• Neuron Structure: Cell body, dendrites, axon.

• Function: Dendrites receive signals; axon sends signals away.

Module 3: Integumentary System

Overview of the Integumentary System

The integumentary system includes the skin and its accessory structures. It protects the body, regulates temperature, and synthesizes vitamin D.

• Cutaneous Membrane: Composed of epidermis and dermis.

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

• Hypodermis: Subcutaneous layer beneath dermis; stores fat and anchors skin.

Epidermis

The epidermis is the outermost layer of skin, composed of stratified squamous epithelium.

• Cell Types: Keratinocytes (main), melanocytes, Langerhans cells, Merkel cells.

• Strata: Layers include stratum basale, spinosum, granulosum, lucidum (in thick skin), corneum.

• Keratinocyte Movement: Cells move from basal layer to surface, changing as they go.

• Thick vs. Thin Skin: Thick skin (palms, soles) has more layers and lacks hair; thin skin covers most of the body.

Dermis

The dermis provides strength and flexibility to the skin and houses accessory structures.

• Layers: Papillary (loose connective tissue) and reticular (dense irregular connective tissue).

• Accessory Structures: Hair follicles, sweat glands, sebaceous glands, sensory receptors.

Skin Pigmentation

Skin color is determined by melanin, carotene, and hemoglobin.

• Melanin: Produced by melanocytes; protects against UV radiation.

• Carotene: Yellow-orange pigment from diet.

• Hemoglobin: Red pigment in blood; affects skin color.

• Albinism: Genetic lack of melanin production.

• Terms: Erythema (redness), pallor (paleness), cyanosis (bluish color).

• Pros/Cons of Melanin: High melanin protects against UV; low melanin increases vitamin D synthesis but raises risk of UV damage.

Accessory Structures

Accessory structures include hair, glands, and nails, each with specialized functions.

• Hair: Provides protection, sensation, and thermoregulation.

• Arrector Pili Muscle: Causes hair to stand up (goosebumps).

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

• Sweat Glands: Eccrine (watery secretion, widespread), apocrine (thicker secretion, axillary/genital regions).

• Sex Hormones: Influence gland secretion, especially during puberty.

• Sebum: Oily secretion that lubricates skin and hair.

Burns

Burns are classified by depth and severity, affecting treatment and prognosis.

• First-degree: Superficial, affects only epidermis, causes redness and pain.

• Second-degree: Affects epidermis and part of dermis, causes blisters.

• Third-degree: Destroys epidermis and dermis, may reach deeper tissues; not initially painful due to nerve damage.