Tissues & The Integumentary System

Overview of Tissues

  • Tissues are layers of cells with specific functions.

  • Four Major Types of Tissues: 1. Epithelial 2. Connective 3. Muscle 4. Nervous

Epithelial Tissue

  • Functions: Protection, secretion, absorption.

  • Characteristics: Lack blood vessels, tightly packed cells, readily divide.

  • Types: Squamous, cuboidal, columnar, transitional, glandular.

  • Simple Squamous: Thin layer, suited for diffusion (e.g., alveoli).

  • Simple Cuboidal: Lines kidney tubules; involved in secretion/absorption.

  • Simple Columnar: In digestive tract; may have microvilli for absorption.

  • Pseudostratified Columnar: Appears layered; involved in mucus movement.

  • Stratified Squamous: Multiple layers for protection (e.g., skin, esophagus).

Connective Tissue

  • Functions: Bind structures, support, protection, fill spaces, store fat, produce blood cells.

  • Characteristics: Cells spaced apart with abundant extracellular matrix.

  • Types: Loose (areolar, adipose), dense, specialized (cartilage, bone, blood).

  • Fibroblasts: Produce fibers; macrophages perform phagocytosis.

  • Types of Cartilage: Hyaline (smooth), elastic (flexible), fibrocartilage (shock-absorbing).

Muscle Tissue

  • Types: 1. Skeletal (voluntary) 2. Smooth (involuntary, internal organs) 3. Cardiac (heart).

  • Skeletal Muscle: Striated, multinucleated, attached to bones.

  • Smooth Muscle: Non-striated, single nucleus, involved in movement through organs.

  • Cardiac Muscle: Striated, branched structure intercalated discs for synchronized action.

Nervous Tissue

  • Components: Neurons (conduct impulses) and neuroglia (support cells).

  • Function: Coordinate and regulate body functions through electrical impulses.

Integumentary System

  • Components: Skin and accessory structures (hair, nails, glands).

  • Function: Protection, temperature regulation, sensation, and vitamin D synthesis.

  • Layers of Skin: 1. Epidermis (outer; protective) 2. Dermis (inner; connective tissue).

Skin and Accessory Structures

  • Epidermis: 4-5 layers; protective, contains melanocytes for pigmentation.

  • Dermis: Contains blood vessels, nerves, and supports epidermis; makes fingerprints.

  • Hair and Nails: Protective structures; nails keratinized for hardness.

  • Glands: Sebaceous (oil) and sudoriferous (sweat) glands regulate skin functions.

Healing and Regeneration

  • Inflammation Symptoms: Redness, heat, swelling, pain from increased blood flow.

  • Wound Healing Process: Involves blood clot formation, migration of fibroblasts, collagen production, scar formation.