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Epithelial Tissue. Chapter 4.1 (Human Anatomy). Histology is the branch of anatomy that studies the structure of animal tissue on a microscopic level. What is a tissue?. A group of cells that all perform the same specific function Example: cardiac, muscle, or nerves. 4 Types of Tissues.
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Epithelial Tissue Chapter 4.1 (Human Anatomy)
Histology is the branch of anatomy that studies the structure of animal tissue on a microscopic level.
Whatis a tissue? • A group of cells that all perform the same specific function • Example: cardiac, muscle, or nerves
4 Types of Tissues • 1) Epithelial Tissue – covers body surfaces and organs, lines body cavities • 2) Connective Tissue – binds and supports body parts
3) Muscular Tissue – contracts producing movement • 4) Nervous Tissue – responds to stimuli and transmits nerve impulses
Epithelial Tissue • Tightly packed cells • Readily divides (mitosis) producing new cells to replace old or damaged cells • Lacks blood vessels • Exists on the skin and on the surface of organs, blood vessels, and body cavities
Function: - Externally – protects body from drying out, injury, and bacterial invasion - Internally – protects, sweeps up impurities, secretes mucus, absorbs
Free Surface Nucleus Cytoplasm Basement membrane • Covers surfaces and lines cavities • Has a free surface • Other surface attached to underlying tissue by the basement membrane Free Surface Nucleus Basement membrane
Simple Epithelial Tissue – composed of a single layer of cells • Stratified Epithelial Tissue – composed of 2 or more layers of cell
Types of Epithelial Tissues 1] Squamous Epithelium: simple and stratified 2] Cuboidal Epithelium 3] Columnar Epithelium 4] Pseudostratified Epithelium 5] Transitional Epithelium
Squamous Epithelium • 2 types of squamous epithelium: * Simple Squamous Epithelium * Stratified Squamous Epithelium
SIMPLE SQUAMOUS EPITHELIUM: – Single layer of flattened cells – Function: secretion, absorption, and filtration – Location: lines the lungs, blood vessels and heart
Simple Squamous Epithelium Cytoplasm Nucleus
STRATIFIED SQUAMOUS EPITHELIUM – Many layers of flattened cells – Function: protection – Location: outer layer of skin, lining the various orifices of the body
Cuboidal Epithelium • Simple Cuboidal Epithelium: - single layer of cube-shaped cells attached to a basement membrane • Stratified Cubiodal Epithelum: two or more layers of cube-shaped cells
Nucleus Free Surface Basement membrane Simple Cuboidal Epithelium
Simple Columnar Epithelium • Composed of cells that are longer than wider • Nucleus found in the lower half of the cell
Free Surface Nucleus Basement membrane
Pseudostratified Epithelium • Cells appear to be layered due to irregularly placed nuclei but each cell touches the basement membrane • May contain cilia – aids in movement of particles • Function: protection, secretion, movement of mucus and sex cells • Location: respiratory tract, reproductive tract
Cilia Nucleus Pseudostratified Epithelium Basement membrane
Transitional Epithelium • Tissue that changes in response to tension • Found in organs that need to stretch • Location: urinary bladder, ureters, urethra
Free Surface Nucleus Basement membrane Transitional Epithelium