Class notes HS 103 (hs103) - Anatomy&Physiology - Chapter 1

Anatomy & Physiology
Chapter 1: Tissues of the Human Body
Unit 1: Epithelial tissue
Epithelial Tissue
o The epithelial tissue includes the outer layer of skin, inner lining of
blood vessels, and the inner lining of all hollow organs such as the
stomach, small intestine, and bladder

The special characteristics of epithelial tissue
o Epithelium generally contains unique characteristics:
o Epithelial tissues are avascular
o Cell membrane junctions:
 Tight junctions
 Desmosomes
 Gap junctions
 Apical surface
 Basement membranes

The functions of epithelial tissue
Epithelial tissue has four main functions:
o Protection: The epithelial layer of skin acts as a barrier and keeps
things like bacteria and chemicals from entering the body.
o Absorption: The digestive system is lined with epithelium that is
specialized for absorption.
o Filtration: The kidneys contain epithelium whose role is absorption
and filtration.
o Secretion: Secretion is a specialty of glandular epithelium.

The classification of Epithelial Tissue
Epithelial tissues are classified based on the shape of their cells and by the
number of cell layers they form. They contain two parts:
Classification based on shape:
o Squamous cells
o Cuboidal cells
o Columnar cells
Classification based on number of layers:
o Simple epithelium (1 cell layer thick)

, o Stratified epithelium (multiple cell layers thick)
o Pseudostratified epithelium (looks like multiple layers but is one layer
thick)

The simple epithelia
The four types of simple Epithelia are:
o Simple squamous epithelium
o Simple cuboidal epithelium
o Simple columnar epithelium
o Pseudostratified columnar epithelium

The Stratified Epithelia
The four types of stratified epithelium are:
o Stratified squamous epithelium
o Keratinized: Stratified squamous epithelium that makes up the
surface of the skin
o Nonkeratinized: The other areas of the body which is not filled
with Keratin
o Stratified cuboidal epithelium
o Stratified columnar epithelium
o Transitional epithelium

The Functions of Glandular Epithelium, Endothelium, and
Mesothelium
o Exocrine glands
o Sweat glands
o Sebaceous glands
o Mucous secreting glands (Goblet cells)
o Salivary glands
o Liver
o Pancreas
o Mammary glands
The inner lining of epithelial tissue that covers lines the lumen of arteries
blood vessels is called endothelium:
o Endothelium
o Vasoconstriction
 Ischemia can be a result of inappropriate vasoconstriction
Important type of epithelial tissue is mesothelium:
o Mesothelium