Hormones

Question 1

What is the difference between an endo/exocrine gland?

Answer 1

Endocrine - gland that secreates hormones directly into the bloodstream (ductless)
Exocrine - gland that secreates molecules into a duct that carries molecules to where they are needed

Question 2

What is a hormone?

Answer 2

A molecule that is released into the blood that acts as a chemical messanger

Question 3

What is the difference between a primary and secondary messanger?

Answer 3

Primary - hormone that acts as a message in the blood stream

Secondary - A chemical inside the cell that is released in response to a hormone binding to a cell surface receptor

Question 4

What does the Adrenal medulla secrete?

Answer 4

Adrenalin (in times of stress)

Question 5

What does the Adrenal cortex secrete, and what are their jobs?

Answer 5

Aldosterone (control Na+ and K+ concentrations)

Cortisol (controls metabolism of CHO)

Question 6

How does adrenaline work?

Answer 6

Adrenaline binds to its complementory receptor on the target cell (in the cell surface membrane)
This activates Adenyl Cyclase
This catalyses the conversion of ATP&raquo_space; cAMP (cyclic AMP) which is the secondary messanger
This then activates other enzymes

Question 7

True or false? The pancreas is both an endocrine and exocrine system

Answer 7

True

Question 8

What does the pancreas produce? And what are they secreated into?

Answer 8

Digestive enzymes

Alkaline pancreatic juice (NaHCO3)

Question 9

What do Alpha cells secrete?

Answer 9

Glucagon

Question 10

What happens when the bloods glucose level is too low?

Answer 10

The drop is detected by the alpha cells in the islets of langerhans
The alpha cells secrete glucagon
The glucagon is detected by receptors on the target cell (hepatocytes in the liver cells)
The hepatocytes convert glycogen&raquo_space; glucose
So the blood glucose level returns normal

Question 11

Explain the mechanism of insulin secreation

Answer 11

K+ ions normally flow out, so the membrane is polarised (-70mv)
When there is an increase of blood glucose, it diffuses into the cell
The glucose is respired to form ATP
The influx of ATP closes the K+ ion channels
This causes a build up of K+ ions inside the cell, so the inside is more positive than the outside
This causes the Ca2+ ion channels to open, and so they flow into cell
This causes the insulin containing vesicles to fuse with the cell surface membrane
Insulin is released by exocytosis

Question 12

True of false? Hyperglycaemia is the state in which the blood glucose concentration is too high

Answer 12

True

Question 13

What type of diabetes mellitus is also termed as late onset?

Answer 13

Type 2