lecture day 2 epithelium and glands

Histology

The study of tissues.

Tissue

A group of cells that work together for a specific function.

Epithelial Tissue

Covers the skin, lines cavities, blood vessels, glands, and ducts.

Functions of Epithelial Tissue

Protection, secretion, absorption, excretion, filtration, and providing sensation.

Avascularity

Condition of epithelial tissue being without blood vessels, relying on connective tissue for nutrients.

Polarity

Characteristic of epithelial tissue that includes an apical surface, lateral surfaces, and a basal surface.

Simple Epithelial Tissue

A single layer of cells.

Stratified Epithelial Tissue

More than one layer of cells.

Simple Squamous Epithelium

Thin, flat cells that facilitate rapid diffusion.

Stratified Squamous Epithelium

Multiple layers of cells that provide protection, becoming flatter toward the surface.

Simple Cuboidal Epithelium

Square-shaped cells involved in secretion and absorption.

Stratified Cuboidal Epithelium

Rare tissue consisting of two or more layers of cuboidal cells providing protection.

Simple Columnar Epithelium

Tall, narrow cells that assist in absorption and secretion.

Pseudostratified Columnar Epithelium

Single layer of varied cell height, appearing stratified, common in the respiratory tract.

Transitional Epithelium

Variable shape cells that allow stretching and recoiling in the urinary bladder.

Endocrine Glands

Ductless glands that produce hormones and secrete them into the blood or interstitial fluid.

Exocrine Glands

Glands with ducts that secrete substances like sweat, oils, and digestive enzymes.

Merocrine Glands

Glands that release products packaged in vesicles.

Apocrine Glands

Glands that release products by pinching off part of the cell.

Holocrine Glands

Glands that release products by cell rupture, causing the cell to die.

Serous Secretions

Watery type of secretion.

Mucous Secretions

Thicker type of secretion.

Mixed Exocrine Secretions

Secretions that have both serous and mucous components.