exam q's

Question 1

adrenal failure is caused by inability of adrenal glands to produce sufficient amount of cortisol and aldosterone
-in healthy people, the hormone ACTH is produced by the pituatry gland and causes the sdrenal cortext to release more coritsol and aldosterone
-a pituatry tumour can stop ACTH production by the pituatry = adrenal failure
-symptoms of adrenal failure include severe fatigue and weekness, weight loss, low blood pressure and salt craving
explain the symptoms of adrenal failure

Answer 1

-cortisol regulates carbohydrate metabolism
-lack of aldosterone causes low blood pressure/ salt craving as it regulates ion concentration

Question 2

explain why patients with a pituitary tumour have adrenal failure but still respond normally to situations of danger or excitement

Answer 2

-ACTH only affects cortex
-adrenaline is produced by medulla
-adrenaline is responsible for fight or flight response

Question 3

suggest why anabolic steroid are effective when applied to the surface of the skin

Answer 3

-skin has large surface area for absorption
-steroids are lipid soluble
-so can cross phospholipid bilayer
-muscles are close to the skin so short diffusion distance

Question 4

describe the different ways in which the pancreas acts as both an endocrine and an exocrine gland

Answer 4

endocrine=
-hormones released directly into blood
-beta cells secrete insulin
-alpha cells secrete glucagon
-alpha and beta cells detect blood glucose concentration

exocrine
-enzymes/ juice released into duct
-pancreatic secretion into small intestine/ duodenum
-hydrogen carbonate it neutralise stomach contents
-lipase and amylase

Question 5

Describe how negative feedback is used to control blood glucose concentration (6)

Answer 5

fi high(er) glucose (concentration) ,
beta / B, cells (ni pancreas) release insulin;
(increased) uptake / absorption, of glucoseb y ,
liver / muscle / effector, cells;
enters through glucose transport proteins
(in cell surface membrane);
glucose converted toglycogen /glycogenesis;
increased (use of glucose in) , respiration / ATP production;

fi lower) glucose (concentration) ,
alpha / a , (in pancreas) cells release glucagon;
(increased) conversion of glycogen to glucose / glycogenolysis;
(increased) conversion of other compounds
(amino acids / lipids) to glucose / gluconeogenesis :