L2

Question 1

what do steroid receptors do?

Answer 1

alter gene expression - change the proteins the cell makes or change what they do

Question 2

what does an ion channel do?

Answer 2

changes membrane conductance - changes the ability of ions to move across the membrane

Question 3

what does a G-protein coupled receptor do?

Answer 3

alters protein activity

Question 4

what does a cytokine receptor do?

Answer 4

regulates many cellular events

Question 5

what are steroids?

Answer 5

molecules chemically based on modifications of cholesterol

Question 6

cortisol is a steroid. where is it produced?

Answer 6

adrenal cortex

Question 7

aldosterone is a steroid. where is it produced?

Answer 7

adrenal cortex

Question 8

progesterone and estradiol are female sex hormones (steroids). where are they produced?

Answer 8

ovaries

Question 9

testosterone and dihydrotesterone are male sex hormones (steroids). where are they produced?

Answer 9

testes

Question 10

what are neurosteroids made by?

Answer 10

neurons and glial cells

Question 11

what is cortisol released in response to?

Answer 11

stress

Question 12

what is aldosterone produced in response to?

Answer 12

fall in blood pressure

Question 13

what steroid are neurosteroids based on?

Answer 13

pregnenolone

Question 14

where do neurosteroids act?

Answer 14

brain

Question 15

are steroids hydrophobic and lipophilic or hydrophilic and lipophobic?

Answer 15

hydrophobic and lipophilic

Question 16

why are lipophilic hormones synthesised on demand?

Answer 16

because they cannot be stored

Question 17

how do lipophilic hormones leave the steroid releasing cell?

Answer 17

diffusion

Question 18

how do lipophilic hormones act on the receptors? what kind of receptor and how does it interact with the cell

Answer 18

crosses cell membrane and acts on intracellular receptors

Question 19

why are all cells exposed to a lipophilic hormone when released into the blood?

Answer 19

because it’s in the blood which goes everywhere and can interact with cells as it is lipophilic

Question 20

what two hormones does stress cause the release of? where from?

Answer 20

cortisol and adrenaline from adrenal gland

Question 21

what are 3 differences between cortisol and adrenaline’s effects, increase in blood and elevation?

Answer 21

• increase in cortisol concentration in blood is slower than adrenaline
• cortisol remains elevated for longer
• cortisol’s effects on target tissues are more prolonged

Question 22

what is the first step of cortisol release?

Answer 22

adrenal cortical cells activated by ACTH via MC2 receptor (ACTH receptor)

Question 23

what occurs after the adrenal cortical cells are activated?

Answer 23

the G-protein coupled receptor is activated

Question 24

what does the activated G-protein coupled receptor do?

Answer 24

increases cAMP

Question 25

what does the increase in cAMP stimulate?

Answer 25

protein kinase A (PKA)

Question 26

what does PKA activate?

Answer 26

transcription factors

Question 27

what does the the stimulation of PKA increase?

Answer 27

increases expression of cortisol synthesising enzymes