A&P Chapter 4 Flashcards
What is epithelial tissue?
A sheet of cells that covers body surfaces or cavities
What are the two main forms of epithelial tissue and where are they located?
- Covering and lining epithelia, located on external and internal surfaces (like skin)
- Glandular epithelia, located in secretory tissues in glands (like salivary glands)
What are the main functions of epithelial tissue?
Protection, absorption, filtration, excretion, and sensory reception
What are the special characteristics of epithelial tissues?
Polarity, apical surface, basal surface, specialized contacts, avascularity, innervated, regeneration, and specialized contacts
What is the polarity (top and bottom) of epithelial tissues?
- The apical surface, upper free side, is exposed to the surface or cavity
- The basal surface, lower attached side, faces inward towards the body
What is the apical surface’s texture?
Most apical surfaces are smooth, but some have specialized fingerlike projections called microvilli
What does the basal surface attach to?
The basal lamina, an adhesive sheet that holds the basal surface of epithelial cells to underlying cells
The apical and basal surfaces differ in ______?
Structure and function
What are the specialized contacts of epithelial tissues?
Epithelial tissues have tightly packed cells, and had desmosomes and tight junctions
Epithelial tissue is _____ by underlying tissue
Nourished
What is regeneration?
Abundant cell division
What are the two names of all epithelial tissues?
First name indicated the number of cell layers, and the second name indicated the shape of the cells
What is the tip to identifying the shape of the cells?
Look at the apical (top) surface to determine cell shape
What are the names for the cell layers?
Simple = one layer and stratified = more than one layer
What are the names for the cell shapes?
Squamous = flat, cuboidal = cube-like, and columnar = taller than it is wide
What is simple squamous epithelium?
A single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm. It is the simplest of epithelia
What is the function of simple squamous epithelium?
Allows materials to pass by diffusion and filtration in sites where protection is not important. It also secretes lubricating substances in serosae
What is serosae?
Linings of the ventral body cavity
What is the location of simple squamous epithelium?
Kidney glomeruli, air sacs of lungs, the lining of the heart, blood vessels and lymphatic vessels, and serosae
What is simple cuboidal epithelium?
Single layer of cube-like cells with large, spherical central nuclei
What is the function of simple cuboidal epithelium?
Secretion and absorption
Where is the location of simple cuboidal epithelium?
Kidney tubules, ducts and secretory portions of small glands, and the ovary surface
What is simple columnar epithelium?
Single layer of tall cells with round to oval nuclei, many cells have microvilli, some have cilia, this tissue may contain goblet cells
What are goblet cells?
Mucus-secreting unicellular glands