Glands

Question 1

What is an endocrine gland?

Answer 1

A ductless gland that secretes directly into blood flowing through them.
Secretions function at distant parts of the body (hormones)
All epithelial cells in the gland secrete the hormones

Question 2

What is an exocrine gland?

Answer 2

A ducted gland that secretes into a location or region of the body through a duct
Secretions are mostly enzymes or lubricants.
Only the cells at the apex of the duct secrete the products (these are called parenchymal cells)

Question 3

Where are simple alveolar ducts found?

Answer 3

Not found anywhere in the adult human body. Found in some stages of foetal development

Question 4

Where are myoepithelial cells found?

Answer 4

Surrounding mucous acini - this is to help move the mucous out of the duct

Question 5

Describe merocrine secretion.

Answer 5

Fusion of vesicles with apical membrane (form of exocytosis)
- e.g. acinar and endocrine glands of pancreas

Question 6

Describe apocrine secretion.

Answer 6

Loss of cytoplasm
- e.g. lactating mammary gland, sweat glands in the axilla and external genitalia

Question 7

Describe Holocrine secretion.

Answer 7

Complete loss of cytoplasm [or cell] (cell dies)
- e.g. sebaceous gland in skin and tarsal glands in eyelid

Question 8

Describe Cytocrine secretion.

Answer 8

Whole cell is released as secretion
- e.g. spermatid (spermatozoa) in seminiferous tubule

Question 9

Define glycosilation

Answer 9

The covalent attachment of sugars by enzymes to proteins and lipids to form glycoproteins and glycolipids

Question 10

What are the 3 mechanisms for hormone release?

Answer 10

• Hormonal (hypothalamus/anterior pituitary gland)
• Neural (nervous system)
• Humoral (changing level of substance in plasma)

Question 11

Where are the parotid glands?

Answer 11

In front of the ear, in the jaw

Question 12

What is the main enzyme secreted by the parotid glands?

Answer 12

Amylase

Question 13

What is the function of a striated duct?

Answer 13

Prevent water loss

Question 14

What kind of cell lines the interlobular and intralobular ducts?

Answer 14

Simple cuboidal epithelial cells

Question 15

What kind of secretions does the parotid gland secrete?

Answer 15

Almost totally serous

Question 16

What kind of secretions does the submandibular gland secrete?

Answer 16

Mostly serous, more mucous

Question 17

What kind of secretions does the lingual gland secrete?

Answer 17

Almost completely mucous

Question 18

How is salivary secretion controlled?

Answer 18

Neural only - no hormonal regulation. Both parasympathetic and sympathetic ANS supply salivary glands and increase salivary secretion

Question 19

What effect does the parasympathetic pathway have on saliva production?

Answer 19

Produces a large volume of watery saliva, rich in enzymes

Question 20

What effect does the sympathetic pathway have on saliva production?

Answer 20

Produces a small, thick secretion of saliva, rich in mucus

Question 21

What are the 2 blood supplies to the liver?

Answer 21

Hepatic portal vein (from small intestine delivers deoxygenated blood containing nutrients)
Hepatic artery (delivers oxygenated blood from general circulation)

Question 22

What is a portal triad made up of?
Where are they found?

Answer 22

Made up of hepatic artery, bile duct and portal vein.
Found in the liver lobules

Question 23

What is a hepatic sinusoid?

Answer 23

Irregularly shaped tube through which blood passes
Connects hepatic artery & portal vein (of portal triad) to hepatic vein.
Sinusoidal cells have large gaps between them

Question 24

What are the different types of capillary vessel?
Where are they found?

Answer 24

• Continuous - brain, most of the body
• Fenestrated - pituitary, small intestine, kidneys, some endocrine glands
• Sinusoid - spleen, bone marrow, liver, lymph nodes

Question 25

What is the function of kupffer cells?

Answer 25

Trap and phagocytose any damaged or aged erythrocytes that were missed by the spleen.
After splenectomy, these cells take over the removal of 120 day old erythrocytes.

Question 26

What kind of cell is a kupffer cell?

Answer 26

Specialised macrophage

Question 27

What is the function of stellate (Ito) cells?

Answer 27

Storage of vitamin A
Found in liver

Question 28

What happens to stellate/Ito cells in liver cirrhosis?

Answer 28

They lose their vitamin A storage capability and differentiate into myofibroblasts, which deposit collagen within the perisinusoidal space, resulting in liver fibrosis

Question 29

What is the main cell type in the liver?

Answer 29

Hepatocytes - constitute 80% of liver cell population

Question 30

List some features of hepatocytes.

Answer 30

• Remarkable regenerative ability
• Numerous mitochondria
• Lots of peroxisomes
• Numerous free ribosomes
• Lots of RER
• Lots of SER
• Numerous Golgi complexes
• Glycogen deposits

Question 31

List the storage functions of the liver.

Answer 31

Metals - iron and copper
Vitamins - A, D, E & K
Sugars - Glucose as glycogen

Question 32

What are the anabolic functions of the liver?

Answer 32

• More than 60% of all the body’s proteins - major plasma proteins, enzymes, lipid carrier proteins
• Amino acid synthesis
• Haemopoiesis in embryo/foetus

Question 33

List the catabolic functions of the liver.

Answer 33

• Drugs
• Hormones
• Haemoglobin - bilirubin passed to gall bladder
• Poisons/toxins
• Sugars - fructose to glucose
• (after splenectomy) removal of aged and damaged RBCs

Question 34

What are some other functions of the liver?

Answer 34

• Bile production - exocrine
• Filtering of cell debris from blood
• Hormones/Growth factor production - endocrine
• Modifies hormones for excretion or function