Tissues - Epithelial Flashcards
4 types of tissues
Epithelial - covering
Connective - support
Nervous - control
Miscle tissues - movement
Location of the epithelial tissues
Body Covering - skin
Body lining - body cavities, gastrointestinal teact
Glandular tissues - excretory tissues or glands
Function of the epithelial tissue
• Protection (skin outer layer, epithelial lining of respiratory tract)
• absorption (digestive system)
• filtration (kidney)
• secretion (glands)
Characteristics of the epithelial tissues
• Cells fit closely together and often form sheets
• Rich in tight junctions and desmosomes except for glandular tissue
• The apical surface is the free surface of the tissue
• The lower surface of the epithelium rests on a basement membrane
• Avascular (no blood supply)
• Regenerate easily if well nourished
Epithelial tissues are classified depending on:
Number of cell layers
Shape of cells
Epithelial tissue types depending on the no. of cell layers
Simple - one layer
Stratified - more than one layer
Epithelial tissue types depending on the shapes of the cells
Squammous cells - flattened like fish scales
Cuboidal cells - cube shaped like dice
Columnar cells - shaped like columns
Types of epithelial tissues
Simple
Simple squamous
Simple cuboidal
Simple columnar
Simple pseudostratified
Stratified
Squamous stratified
Cuboidal stratified
Columnar stratified
Transitional stratified
Simple squamous epithelium
• One layer of squamous cells
• The cells fit tightly together
• Form membranes where diffusion and filtration occur
• Form the air sacs of the lungs (alveoli), where oxygen and carbon dioxide exchange (diffusion)
• Form the walls of capillaries that allow nutrients and gases to pass between the blood and the intersitial fluid (filtration)
Function of the basement membrane
Provide nutrients to the upper layer of the cell
Simple cuboidal epithelium
• One layer of cuboidal cells
• The function of the simple cuboidal tissue is mainly for secretion and absorption
• Forms the walls of the kidney tubules (function: secretion and absorption)
• Forms glands and their associated small tubes called ducts (function: secretion) (e.g: salivary glands and pancreas)
• Covers the surface of the ovaries (function: secretion)
• Forms the ciliated cells (function: move small particles and debris, assist the movement of mucus that may be produced by other cells.
Type of tissues in the respiratory system
Nose/ Trachea/ Bronchi ——> pseudostratified columnar epithelium
Bronchioles ——> simple cuboidal epithelium
Alveoli ——> simple squamous epithelium
Simple columnal epithelium
• One layer of columnal tall cells
• Mostly important for absorption and secretion
• Lines the entire length of the digestive tract from the stomach to the anus (function: absorption and secretion)
• The mucous membrane (mucosa) lines body cavities that are open to the exterior. There are goblet cells that produce lubricating mucus. (Function: secretion)
Mucous is made from which type of cells?
Goblet cells
What does the term “pseudo” means?
False