Epithelium

Question 1

What are the 4 major types of tissues in the body? Which of these has major subdivisions?

Answer 1

• Epithelium
• Connective tissue
• Nervous tissue
• Muscle tissue
• Connective tissue has the major subdivisions

Question 2

What is the terminal bar?

Answer 2

At the light microscope level of resolution:

• zonula occludens
• zonula adherens
• macula adherens

Question 3

What is the structure and function of cilia?

Answer 3

Structure: Relatively long motile processes, shaft covered with plasma membrane; axoneme is composed of central doublet and 9 peripheral pairs of fused double microtubules

Function: Move like wheat field (metachronal: sequential beating), done by dyneins and nexin link

Question 4

What is the structure and function of flagella?

Answer 4

Structure: same axial structure as cilia, but longer..only 1 or 2 per cell

Function: beat is more random and whiplike

Question 5

Stereocilia

Answer 5

• Unusually long microvilli; apical ends tend to twist together
• non-motile
• increase absorptive surface of cells

Question 6

Microvilli

Answer 6

• Has a core of microfilaments, contains actin

- Greatly increases S.A. of cell

Question 7

What is the serous membrane composed of?

Answer 7

• Mesothelium + basement membrane + underlying connective tissue
• lines closed cavities of the body

Question 8

What is the mucous membrane composed of?

Answer 8

• Surface epithelium + basement membrane + underlying connective tissue
• Lines cavities and canals which connect with exterior

Question 9

What is the basement membrane composed of?

Answer 9

• Lamina lucida: rich in glycoproteins
• Lamina densa: basically peanut butter (type IV collagen) sandwhiched by two slices of thin bread (proteoglycan perlacan)