2. Glandular Tissues and How Cells Secrete

Question 1

Define gland.

Answer 1

An epithelial cell or a collection of cells specialised for secretion.

Question 2

What are the four means of classifying glands?

Answer 2

The destination of secretion, the structure of the gland, the nature of the secretion, the method of discharge.

Question 3

What is the difference between exocrine and endocrine glands?

Answer 3

Exocrine glands have ducts but endocrine don’t, so they secrete straight into the bloodstream.

Question 4

Is the goblet cell unicellular or multicellular?

Answer 4

Unicellular.

Question 5

Where can goblet cells be found?

Answer 5

In the upper respiratory epithelium.

Question 5

Give an example of a simple tubular gland.

Answer 5

Intestinal glands.

Question 6

Give an example of a simple branched tubular gland.

Answer 6

Gastric glands, mucous glands of oesophagus, tongue or duodenum.

Question 7

Give an example of a simple coiled tubular gland.

Answer 7

Merocrine sweat gland.

Question 8

Give an example of a simple branched alveolar gland.

Answer 8

Sebaceous glands.

Question 9

Give an example of a simple alveolar/ acinar gland.

Answer 9

Not in adults, in developing simple branched glands.

Question 10

Give an example of a compound tubular gland.

Answer 10

Mucous glands in mouth, bulbourethral glands in male reproductive system or testes.

Question 11

Give an example of a compound alveolar gland.

Answer 11

Mammary glands.

Question 12

Give an example of a compound tubuloalveolar gland.

Answer 12

Salivary glands, glands of respiratory passages or pancreas.

Question 14

Describe two difference between mucous and serous glands.

Answer 14

Mucous gland secretions contain mucus and are rich in mucins, but serous secretions are watery and free of mucous.
Serous glands turn pink with H and E stains but mucous glands stain poorly.

Question 14

Describe the process of apocrine secretion.

Answer 14

Non-membrane bounded structure approaches the cell surface.
It makes contact and pushes up the apical membrane.
A thin layer of apical cytoplasm drapes around the droplet.
The membrane surrounding the droplet pinches off from the cell.
The plasma membrane becomes smaller temporarily but then more is added to return it to the original size.

Question 15

Describe the process of merocrine secretion.

Answer 15

Membrane bounded component approaches the cell surface.
Membrane fuses with the plasma membrane.
Contents empty into extra cellular space.
The plasma membrane becomes larger temporarily but then returns to normal size as cell surface area is stabilised.

Question 16

What are the three key stages of holocrine secretion?

Answer 16

Disintegration of the cell.
Release of contents.
Discharge of the whole cell.

Question 17

Define endocytosis.

Answer 17

Material being engulfed that was originally outside the cell.

Question 18

What is transepithelial transport?

Answer 18

Endocytosis and exocytosis coupled together.

Question 19

What happens in transepithelial transport?

Answer 19

Material is endocytosed at one surface, a transport vesicles shuttles it across the cytoplasm and it is exocytosed at the opposite surface.

Question 20

What is the structure of the Golgi apparatus?

Answer 20

A stack of disc-shaped cisternae with one side of the discs flattened and the other concave. The discs have swellings at the edges which pinch off as migratory Golgi vacuoles.

Question 21

What is the function of the Golgi apparatus?

Answer 21

Sorting into compartments and packaging by condensation of contents. Glycosylation (adding sugars to proteins and lipids) and transport of resultant vesicles.

Question 22

Where are the three destinations of vesicles produced by the Golgi apparatus?

Answer 22

Mostly extruded in secretory vesicles. But some are kept in the cells or in the plasma membrane.

Question 23

What four types of control is secretion under?

Answer 23

Nervous, endocrine, neuro-endocrine and negative feedback chemical mechanism.

Question 24

What are the names of the three major salivary glands?

Answer 24

Parotid, submandibular and sublingual.

Question 25

What is the problem with exocrine secretions in CF patients?

Answer 25

There is too little water so the secretions are thickened and ducts become blocked. The exocrine pancreas gets inflamed and fibrotic.

Question 26

What are some results of insufficient secretion of exocrine enzymes of the pancreas in CF patients?

Answer 26

Faecal excretion of undigested fat (normally as diarrhoea) and malabsorption.

Question 27

What are the steps in thyroid hormone synthesis?

Answer 27

Synthesis and secretion of thyroglobulin.
Uptake and concentration of iodide from blood, oxidation to iodine and released into colloid.
Iodisation of thyroglobulin in the colloid.
T3 and T4 hormones formed by oxidative coupling reactions.
Resorption of colloid by receptor-mediated endocytosis.
Release of T3 and T4 from cell by exocytosis?

Question 28

What do the principal/ chief cells of the parathyroid gland secrete?

Answer 28

Parathyroid hormone.