5 Glands (1)

Question 1

Define ‘Gland’

Answer 1

Aggregate of epithelial cells- specialised for substance secretion

Question 2

Differentiate between Endocrine and Exocrine glands.

Answer 2

• Endocrine=ductless
  
  • Hormones (to different parts of body)
  • All cells secrete
• Exocrine=ducted
  
  • Enzymes and lubricants
  • Only cells at apex secrete product

Question 3

Give examples of endocrine and exocrine glands

Answer 3

Exocrine-

• Salivary
• Pancreas
• Sweat
• Sebaceous

Endocrine-

• Thyroid
• Pituitary

Question 4

How are Glands generated (in utero)?

Answer 4

1. Growth Signal
2. Cell proliferation
3. Epithelial cells- invade space created

4 EXOCRINE.

Central cells die off- duct created

4 ENDOCRINE.

Produce growth factors-stimulate blood vessel growth

Link to mother cells=broken (apoptosis)

Question 5

How does branching of glands occur?

Answer 5

• Growth factor- released by fibroblast
• Cell _moves towards signa_l=branching/elongation

Question 6

Label each duct type: (GREEN)

Answer 6

Question 7

Give an example of each type of the following glands found in the body:

• Simple tubular
• Simple branched tubular
• Simple alveolar
• Simple branched alveolar
• Compound tubular
• Compound alveolar
• Compound tubuloalveolar

Answer 7

• Simple tubular- ONLY intestinal glands
• Simple branched tubular- stomach (gastric glands)
• Simple branched alveolar- sebaceous branched alveolar
• Compound tubular- duodenal glands- small intestine
• Compound alveolar- mammary glands
• Compound tubuloalveolar- salivary glands

(alveolar aka acinar)

Question 8

Diffferentiate between Merocrine, Apocrine and Holocrine.

Answer 8

• Merocrine- secretory vesicles
• Apocrine-pinched of portion of cell
• Holocrine- Mature cells dies= secretory product

Question 9

What are the 2 different types of secretion carried out by merocrine glands?

Answer 9

1. Constitutive: Small vesicles, proteins not modified, continually released
2. Regulated: large vesicles, exocytosis- require Ca²⁺ ions

Question 10

State an example of regulated secretion from a merocrine gland.

Answer 10

Insulin release- pancreas

Beta cell- glucose enters- metabolised. Increase ATP, increase K ions, membrane depolarised, Ca into cell- vesicle moves to plasmolemma, insulin released

Question 11

State an example of secretion from an apocrine gland

Answer 11

During lactation- fats and proteins

Question 12

Give an example of holocrine secretion.

Answer 12

Sebacious gland

• cell fills up with secretory granules
• organelles degenerate
• cells die
• plasma membrane breaks
• contents released

Question 13

What is the function of golgi apparatus?

Answer 13

Glycosylates proteins

Packages them into large secretory vesicles

Question 14

What is ‘glycosylation’?

Answer 14

Covalent attachment of sugar (by enzymes) to proteins and lipids

–> form GLYCOPROTEINS and GLYCOLIPIDS

(approx 50% pf all cellular proteins)

Question 15

What is the function of glycosylation?

Answer 15

1. Aid protein folding
2. Prevent digestion of proteins and lipids by intracellular proteases

Question 16

Why does every cell do pinocytosis? (Ingest liquid droplets)

Answer 16

To sample external environment

Question 17

How are each of the transepithelial transport processes occurring in the following diagrams?

Answer 17

A= Passive Diffusion

B=Lipids across cell membranes (eg steroid hormones)

C=Carrier proteins

D= Bind to receptors and engulfed (Cholestrol)

Question 18

What are the 3 mechanisms used for glandular control?

Answer 18