Chapter 4 - Tissue Level of Oganization Flashcards
Epithelial Tissue Location
Every exposed body surface
Epithelial Function
Provides physical protection, controls permeability and absorption, secretion and filtration
Cellularity of epithelial tissue
composed of closely packed cells with very little intracellular material
Specialized contacts of epithelial tissue
cells that fit close together by means of tight junctions
Polarity of epithelial tissue
Always have an exposed surface and a basal surface attached to another tissue. cytoplasmic components are unevenly distributed.
Avascularity of epithelial tissue
No blood vessels nutrients are obtained by diffusion or absorption. there is also a large nerve supply.
Basal Lamina of epithelial tissue
Layer found next to the connective tissue
Regeneration of epithelial tissue
Continuous cell division
Basement Membrane of epithelial tissue
Consists of a layer closer to the epithelium, a basal lamina and reticular lamina, the deepest layer.
Squamous epithelial cells
usually, thin, flat, irregular, and nucleus is newar the surface
Cuboidal epithelial cells
Look like cubes, hexagonal shaped. Nucleus is in the center
Columnar epithelial cells
Tall with the nucleus near the basement membrane
Simple Squamous Epithelia
Flat and scale-like. Absorption, secretion, and filtration by diffusion. Large nucleus and little cytoplasm. Found in airsacs of lungs, kidney, heart, and blood vessels.
Simple Cuboidal Epithelia
Single later, tall and wide. Function in secretion and absorption. Found in kidney microvilli, glands, and ovules.
Simple Columnar Epithelia
Tall, closely-packed, oval nucleus towards the bottom. Used for absorption and secretion. If secretion, elaborate golgi apparatus and ER. Found in digestive tract, where there’s dense microvilli, goblet cells. Found ciliated in oviducts and respiratory tract.
Stratified Squamous Epithelia
External skin surface. Several layers, squamous on surface, basal cuboidal or columnar (can be mixed). Covers the tongue, mouth, and vagina.
Stratified Cuboidal Epithelia
Mostly in glands. Very rare
Stratified Columnar Epithelia
Rare, used for protection and secretion. in stomach junction, pharynx, and male urethra.
Pseudostratified Epithelia
One layer, but looks like more
Transitional Epithelia
Lining of the urinary organs. It stretches.
Mucus membrane
Lines body cavities, open to the exterior. There for absorption and secretion. Have a lamina propria, connective tissue lying under the epithelial sheet
Cutaneous Membrane
Found in the skin
Serous membrane
Found in ventral body cavities. Most have a visceral and a parietal layer. They protect and lubricate.
Gland
one or more cells that produce and secrete a product