Exam Study Guide: Integumentary, Skeletal, and Muscular Systems

Overview

This study guide outlines the key topics and learning objectives for an upcoming Anatomy & Physiology exam, covering the integumentary system, bone tissue and structure, and muscle tissue structure and function. The exam will include multiple choice and short answer questions, with a focus on understanding structure, function, and physiological processes.

Integumentary System

Structure and Function

• Integumentary System: The organ system that protects the body from external damage, regulates temperature, and provides sensory information.

• Main Components: Skin, hair, nails, glands, and associated structures.

Layers of the Integument

• Cutaneous Layer: The skin itself, consisting of two main layers:

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

  • Dermis: Deeper connective tissue layer containing blood vessels, nerves, and glands.

  • Hypodermis (Subcutaneous Layer): Not technically part of the skin, but connects skin to underlying tissues and stores fat.

Thick vs. Thin Skin

• Thick Skin: Found on palms and soles; contains a thicker epidermis and an additional stratum lucidum layer.

• Thin Skin: Covers most of the body; thinner epidermis, lacks stratum lucidum.

Strata of the Epidermis (from deep to superficial)

1. Stratum basale

2. Stratum spinosum

3. Stratum granulosum

4. Stratum lucidum (only in thick skin)

5. Stratum corneum

Cell Types in the Epidermis

• Keratinocytes: Produce keratin for waterproofing and protection.

• Melanocytes: Produce melanin pigment, giving skin its color.

• Langerhans Cells: Immune defense.

• Merkel Cells: Sensory receptors for touch.

Accessory Structures

• Hair: Provides protection and sensory input.

• Nails: Protect distal phalanges and aid in manipulation.

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

Sensation and Insensible Perspiration

• Sensation: Skin contains receptors for touch, pain, temperature, and pressure.

• Insensible Perspiration: Water loss through the epidermis not perceived as sweat.

Tension Lines

• Tension (Langer's) Lines: Patterns of collagen fiber orientation in the dermis; incisions parallel to these lines heal better.

Vitamin D Production

• Skin synthesizes vitamin D when exposed to UV light, essential for calcium absorption.

Disorders and Effects of Aging

• Vitamin D Deficiency: Can lead to rickets in children and osteomalacia in adults.

• Aging: Thinner skin, reduced elasticity, slower healing, and decreased gland activity.

Wound Healing Phases

1. Inflammation

2. Migration

3. Proliferation

4. Scarring

Cell Types in Tissues

• Permanant Cells: Do not divide (e.g., neurons).

• Labile Cells: Divide continuously (e.g., skin, GI tract).

• Stable Cells: Divide only when needed (e.g., liver).

Skeletal System

Structure and Function

• Functions: Support, protection, movement, mineral storage, blood cell production, and energy storage.

Bone Composition

• Cells: Osteogenic cells, osteoblasts (build bone), osteocytes (maintain bone), osteoclasts (break down bone).

• Matrix: Collagen fibers (flexibility) and hydroxyapatite (strength).

Bone Formation (Ossification)

• Endochondral Ossification: Bone forms from cartilage (most bones).

• Intramembranous Ossification: Bone forms directly from mesenchyme (flat bones of skull).

Epiphyseal Plate

• Growth plate where bone lengthening occurs; closure marks end of growth.

Bone Repair

• Steps: Hematoma formation, fibrocartilaginous callus, bony callus, bone remodeling.

Types of Bones

• Long, short, flat, irregular, sesamoid.

Calcium Homeostasis

• Regulated by parathyroid hormone (PTH), calcitonin, and vitamin D.

Osteoporosis

• Risk factors: Age, sex, genetics, inactivity, low calcium/vitamin D.

Axial vs. Appendicular Skeleton

• Axial: Skull, vertebral column, rib cage.

• Appendicular: Limbs and girdles.

Muscle Tissue Structure and Function

Types of Muscle Tissue

• Skeletal Muscle: Voluntary, striated, multinucleated.

• Cardiac Muscle: Involuntary, striated, branched, intercalated discs.

• Smooth Muscle: Involuntary, non-striated, spindle-shaped.

Structure of Skeletal Muscle

• Muscle fibers (cells) organized into fascicles, surrounded by connective tissue (endomysium, perimysium, epimysium, fascia).

• Each muscle fiber contains myofibrils, which are composed of sarcomeres (the contractile units).

Sarcomere Structure

• Composed of thick (myosin) and thin (actin) filaments, with regions called A band, I band, H zone, Z disc, and M line.

Sliding Filament Model

• Muscle contraction occurs as myosin heads bind to actin and pull, shortening the sarcomere.

Excitation-Contraction Coupling

• Process linking muscle fiber stimulation to contraction.

• Involves release of calcium ions, binding to troponin, and exposure of binding sites on actin.

Neuromuscular Junction

• Synapse between motor neuron and muscle fiber.

• Acetylcholine (ACh) is released, binds to receptors, and initiates action potential in muscle.

• ACh is broken down by acetylcholinesterase to terminate the signal.

Muscle Twitch and Summation

• Muscle Twitch: Single contraction-relaxation cycle.

• Summation: Increased force by repeated stimulation.

• Tetanus: Sustained contraction (incomplete or complete).

Energy for Contraction

• ATP is required for contraction and relaxation.

• Sources: Creatine phosphate, anaerobic glycolysis, aerobic respiration.

Effects of Exercise and Aging

• Exercise increases muscle size, strength, and endurance.

• Aging leads to muscle atrophy, decreased strength, and slower repair.

Key Table: Comparison of Muscle Tissue Types

Key Equations

• Calcium Homeostasis:

• Sliding Filament:

Additional info: This guide expands on the exam outline by providing definitions, examples, and context for each topic, ensuring a comprehensive review for students preparing for the exam.