Anatomy & Physiology Study Guide: Tissues, Integumentary System, Skeletal System, Joints, and Muscular System

Chapter 4: Tissues and Glands

Types and Functions of Tissues

Tissues are groups of cells with similar structure and function. There are four primary types of tissues in the human body, each with distinct roles.

• Epithelial tissue: Covers body surfaces, lines cavities, and forms glands. Functions include protection, absorption, secretion, and sensation.

• Connective tissue: Supports, binds, and protects organs. Includes bone, cartilage, adipose, and blood.

• Muscle tissue: Responsible for movement. Types include skeletal, cardiac, and smooth muscle.

• Nervous tissue: Conducts electrical impulses and processes information.

Example: The skin contains epithelial tissue (epidermis), connective tissue (dermis), muscle tissue (arrector pili), and nervous tissue (sensory receptors).

Epithelial Tissue Classification and Functions

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

• Functions: Protection (skin), absorption (intestines), secretion (glands), filtration (kidneys).

• Key characteristics: Polarity, specialized contacts, supported by connective tissue, avascular but innervated, high regenerative capacity.

Major criterion for classification: Number of cell layers and cell shape.

Glands: Endocrine vs. Exocrine

• Endocrine glands: Secrete hormones directly into the bloodstream (e.g., thyroid gland).

• Exocrine glands: Secrete products into ducts (e.g., sweat, salivary glands).

• Merocrine, holocrine, apocrine: Methods of secretion. Merocrine (exocytosis), holocrine (cell rupture), apocrine (pinching off).

Connective Tissue Types and Functions

• Types: Loose (areolar, adipose, reticular), dense (regular, irregular, elastic), cartilage, bone, blood.

• Functions: Support, protection, transport, insulation, storage.

• Structural elements: Cells (fibroblasts, chondrocytes, osteocytes), fibers (collagen, elastic, reticular), ground substance.

Muscle and Nervous Tissue

• Muscle tissue: Skeletal (voluntary movement), cardiac (heart contraction), smooth (walls of organs).

• Nervous tissue: Neurons (conduct impulses), neuroglia (support cells).

Tissue Repair

• Steps: Inflammation, organization (restores blood supply), regeneration (replacement of destroyed tissue).

• Superficial wound healing: Involves epithelial regeneration and minimal scarring.

Chapter 5: Integumentary System

Structure and Function of Skin

The integumentary system includes the skin, hair, nails, and glands. It serves as the body's first line of defense.

• Layers: Epidermis (outer), dermis (middle), hypodermis (deepest).

• Functions: Protection, temperature regulation, sensation, metabolic functions, blood reservoir, excretion.

Epidermal Layers and Cells

• Layers (deep to superficial): Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum (only in thick skin), stratum corneum.

• Cells: Keratinocytes (produce keratin), melanocytes (produce melanin), Langerhans cells (immune), Merkel cells (sensory).

Dermis and Hypodermis

• Dermis: Papillary layer (areolar connective tissue), reticular layer (dense irregular connective tissue).

• Hypodermis: Adipose tissue, anchors skin to underlying structures.

Skin Color and Pigments

• Pigments: Melanin, carotene, hemoglobin.

• Function: Protection from UV radiation, determination of skin color.

Hair, Nails, and Glands

• Hair: Protection, sensory input, thermoregulation.

• Nails: Protect distal phalanges, aid in grasping.

• Glands: Sweat (eccrine, apocrine), sebaceous (oil).

Skin Cancer and Risk Factors

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

• Risk factors: UV exposure, genetics, fair skin.

Chapter 6: Skeletal System

Functions and Classification of Bones

The skeletal system provides support, protection, movement, mineral storage, and blood cell formation.

• Functions: Support, protection, movement, mineral storage, hematopoiesis.

• Classification: Long, short, flat, irregular, sesamoid bones.

Bone Structure and Composition

• Structure: Diaphysis, epiphyses, metaphysis, medullary cavity, periosteum, endosteum.

• Composition: Organic (collagen, cells), inorganic (hydroxyapatite).

Microscopic Anatomy of Bone

• Compact bone: Osteons (Haversian systems), lamellae, central canal, canaliculi.

• Spongy bone: Trabeculae, marrow spaces.

Bone Development and Growth

• Ossification: Endochondral (from cartilage), intramembranous (from membrane).

• Growth: Interstitial (length), appositional (thickness).

Bone Remodeling and Repair

• Remodeling: Continuous process of bone resorption and formation.

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

Osteoporosis

• Definition: Disease characterized by decreased bone mass and increased fracture risk.

• Risk factors: Age, gender, hormonal changes, lack of exercise, poor nutrition.

Chapter 8: Joints (Articulations)

Classification and Function of Joints

Joints, or articulations, are sites where two or more bones meet. They allow movement and provide stability.

• Types: Fibrous (immovable), cartilaginous (slightly movable), synovial (freely movable).

• Functions: Movement, stability, support.

Synovial Joints

• Features: Articular cartilage, joint cavity, synovial fluid, articular capsule, ligaments, nerves, blood vessels.

• Types: Plane, hinge, pivot, condyloid, saddle, ball-and-socket.

• Movements: Flexion, extension, abduction, adduction, rotation, circumduction.

• Stabilizing factors: Shape of articular surfaces, ligaments, muscle tone.

Joint Injuries

• Common injuries: Sprains, dislocations, cartilage tears.

• Symptoms: Pain, swelling, reduced mobility.

Chapter 9: Muscular System

Functions and Characteristics of Muscle Tissue

Muscle tissue is specialized for contraction, enabling movement, posture, and heat production.

• Functions: Movement, posture, joint stabilization, heat generation.

• Special characteristics: Excitability, contractility, extensibility, elasticity.

Structure of Skeletal Muscle

• Connective tissue sheaths: Epimysium (surrounds whole muscle), perimysium (surrounds fascicles), endomysium (surrounds muscle fibers).

• Nerve and blood supply: Each muscle fiber is innervated and supplied with blood for nutrients and oxygen.

Microscopic Anatomy

• Myofibrils: Rod-like structures containing sarcomeres.

• Sarcomere: Functional unit of contraction; contains thick (myosin) and thin (actin) filaments.

• Sarcoplasmic reticulum: Stores calcium ions.

• T tubules: Invaginations of the sarcolemma that transmit action potentials.

Muscle Contraction

• Sliding filament model: Myosin heads bind to actin, pulling filaments past each other.

• Excitation-contraction coupling: Sequence of events from action potential to contraction.

• Role of calcium: Triggers contraction by binding to troponin.

$\text{Force} = \text{Number of cross bridges} \times \text{Force per bridge}$

Neuromuscular Junction and Muscle Activation

• Neuromuscular junction: Site where motor neuron stimulates muscle fiber.

• Action potential: Electrical signal that initiates contraction.

Muscle Responses and Types

• Motor unit: A motor neuron and all the muscle fibers it innervates.

• Muscle twitch: Response of a muscle to a single stimulus.

• Graded responses: Variation in contraction strength due to stimulus frequency and strength.

• Types of skeletal muscle fibers: Slow oxidative, fast oxidative, fast glycolytic.

Muscle Fiber Type	Contraction Speed	Fatigue Resistance	Main Energy Source
Slow oxidative	Slow	High	Aerobic respiration
Fast oxidative	Fast	Intermediate	Aerobic respiration
Fast glycolytic	Fast	Low	Anaerobic glycolysis

Additional info: Some details, such as the specific steps of tissue repair and the phases of muscle twitch, were expanded for academic completeness.