Glands

Question 1

Define a gland

Answer 1

An aggregate of epithelial cells specialised for substance secretion

Question 2

What is the difference between endocrine and exocrine glands?

Answer 2

Endocrine are ductless and secrete hormones directly into the blood
Exocrine are ducted and secrete lubricants/enzymes via a duct

Question 3

Give two examples of endocrine and exocrine glands

Answer 3

Endocrine - thyroid, parathyroid, pituitary

Exocrine - salivary, pancreas, mammary

Question 4

What are the two types of duct branching?

Answer 4

Tubule elongation and tubule branching

Question 5

What are the 3 modes of gland secretion?

Answer 5

• Merocrine
• Apocrine
• Holocene

Question 6

What are the two types of exocrine gland epithelial cells?

Answer 6

• Cells that line the ducts

- Cells that secrete products (myoepithelial)

Question 7

Describe merocrine gland secretion and what are its two types?

Answer 7

• Vesicles move to the cell membrane and fusion releases the contents
• Regulated and constitutive

Question 8

What is apocrine gland secretion?

Answer 8

Vesicles are secreted with part of the original cell cytoplasm

Question 9

What is holocrine gland secretion?

Answer 9

The cell enlarges, bursts and its contents are released

Question 10

Give an example of a merocrine gland secretion

Answer 10

• Regulated secretion of insulin from beta cells
• Glucose enters cell and closes K+ channels
• Membrane depolarises and Ca2+ channel opens
• Insulin extracellular secretion occurs

Question 11

Give an example of apocrine gland secretion

Answer 11

• Breast tissue
• Fat builds up in the cell during lactation
• Cells become unstable and break releasing the fat

Question 12

Give an example of holocrine gland secretion

Answer 12

• Sebaceous gland
• Secretory cell fills up and cell dies
• Contents released and cell replaced by Mitosis

Question 13

What is glycosylation and where does it occur?

Answer 13

The modification of proteins or lipids by covalently bonding sugars in the Golgi Apparatus

Question 14

What are the products of glycosylation?

Answer 14

Glycoproteins and glycolipids

Question 15

Name 2 roles of glycosylation

Answer 15

• Aid protein folding
• Prevent protein/lipid digestion
• Cell recognition

Question 16

What are the 4 types of cell secretory mechanisms and how do they work?

Answer 16

Endocytosis - Engulfing by vesicle formation
Exocytosis - Secretion by the vesicle fusing to cell membrane
Phagocytosis - Immune cells engulf other cells/particles
Pinocytosis - Liquid droplets ingested to sample the environment

Question 17

Name 3 types of transepithelial transport

Answer 17

• Paracellular
• Transcellular
• Carrier Protein
• Endocytosis
• Exocytosis

Question 18

How do endocytosis and secretion combine in transepithelial transport?

Answer 18

Proteins/Hormones are moved to and across the cell membrane using endocytosis and secreted so they can travel along the epithelial surface

Question 19

Give 3 mechanisms of gland secretion control

Answer 19

• Hormonal
• Neural
• Humoral

Question 20

Describe one control mechanism for hormonal secretion

Answer 20

• Negative feedback mechanism

nervous system > endocrine gland > target cells > action

Question 21

Give 2 examples of transepithelial transport

Answer 21

• Amino acids for hormone production
• Steroid hormones
• Thyroxine transport
• Cholesterol transport

Question 22

How do the hypothalamus and pituitary glands communicate?

Answer 22

Neuroendocrine communication