WEEK 11 (Types of Epithelium and Secretory functions)

Question 1

What are the properties of Microvilli?

Answer 1

• Small membrane projections
• Contain cores of actin filaments
• Increase the epithelial cell’s apical surface area for absorption

Question 2

What are the properties of Stereocilia?

Answer 2

• Long microvilli
• Specialised mechanosensory function in cells of the inner ear
• Absorption in tissues of the male reproductive tract

Question 3

What are the properties of Cilia?

Answer 3

• Large projecting structures
• Contain a well-organised core of microtubules
• Restricted, dynein-based sliding of microtubules causes ciliary movement that propel material along an epithelial surface

Question 4

What is the difference between Simple and Stratified cells?

Answer 4

One cell layer is SIMPLE

Two or more layers of cells is STRATIFIED

Question 5

What are the properties of Stratified squamous epithelia?

Answer 5

• Move gradually from the basal to the surface layers, changing shape and becoming filled with KERATIN intermediate filaments
• Cover the body surface
• Protect underlying tissues from excess water loss and microbial invasion

Question 6

What are the properties of Pseudostratified epithelia?

Answer 6

• Thick
• Appear to have several cell layers
• All cells attach to the basal lamina but not all extend to the free epithelial surface

Question 7

What are the properties of the Transitional Epithelium/Urothelium?

Answer 7

• Found only in the lining of the urinary system
• Stratified
• Contain large rounded surface cells which are protective against urine

Question 8

What are the properties of Exocrine glands?

Answer 8

• Contain epithelial ducts carrying secretions to specific sites
• Ducts of SIMPLE GLANDS are unbranched and ducts of COMPOUND GLANDS are branched
• Secretory portions form round, saclike ACINI/ALVEOLI

Question 9

What are the properties of Endocrine glands?

Answer 9

• Lack ducts
• Secreted substances (Hormones) are carried by interstitial fluid and blood with specificity produced by hormone receptors of target cells

Question 10

What are the three basic secretory mechanisms?

Answer 10

• MEROCRINE = uses exocytosis
• HOLOCRINE = terminally differentiated cells filled with lipid product are released
• APOCRINE = apical, product-filled areas of cells are forced out

Question 11

What are exocrine glands that produce mucous called?

Answer 11

Mucous glands

Question 12

How do mucous glands stain?

Answer 12

Oligosaccharide components of mucus stain POORLY with routine dyes but stain well with PAS stain

Question 13

What are Serous glands?

Answer 13

Exocrine glands producing largely enzymes

Question 14

How do Serous glands stain?

Answer 14

Darkly with H&E due to the cell’s content of RER and secretory granules