Epithelial Tissue

Question 1

What are the ways to classify epithelial tissue?

Answer 1

Layers- one layer is simple, more than 1 is stratified.
Shapes- squamous (flattened), cuboidal (w ~h), columnar (h>w).
Outermost layer- cillia etc, keratin.

Question 2

Where can you find epithelial tissue?

Answer 2

Lines body cavities, covers body surfaces, and secretory and excretory parts of glands.
It may also be innervated.

Question 3

What are some characteristics of epithelial tissue?

Answer 3

It has relatively uniform geometric shape from the side.
Tightly bound together to form tissues
Little intercellular matrix
Typically displays free surfaces

Question 4

How do epithelial cells exhibit polarity?

Answer 4

Apical domains- part of the cell that is contact with the lumen or external environment- characterized by surface modifications.
Basolateral domains- located on the sides and base of cells. Characterized by intercellular junctions that lock the cells together. The base is in contact with the basal lamina and lateral domains ( surrounding cells).

Question 5

Do epithelial cells contain blood vessels?

Answer 5

No, they receive their nutrients through diffusion.

Question 6

What epithelial tissues are derived from each primary germ layer?

Answer 6

Ectoderm- skin and glands
Endoderm- lining of organs
Mesoderm- lining of blood vessels, mesothelium, and bowman’s capsule.

Question 7

Epithelial tissues sit atop what membrane?

Answer 7

Basement membrane, composed of two parts:
Basal lamina- top layer (absent in lymph vessels and hepatic sinusoids)
Reticular lamina- connects to the underlying connective tissue

Question 8

What is the function of the basement membrane?

Answer 8

Selective filter
Scaffold of embryogenesis and regeneration
Stabilization of tissue shapes

Question 9

What are the epithelial special cases?

Answer 9

Pseudostratified- it looks like multiple layers, but it’s really just one. It looks that way because of the varied position of the nuclei but in actuality all of the cell’s touch the basal lamina.
Transitional- looks like multiple layers but it’s actually simple, has dome shaped cells that are only in transitional epithelium. Located in the urinary tract.

Question 10

Finish the sentence: Epithelial tissue is the most..

Answer 10

Cellular tissue in the body