neuroendocrinology- week 2

Question 1

what is the neuroendocrine system ??

Answer 1

NS uses neurotransmitters to relay messages through neurones

endocrine system uses hormones in the blood

Question 2

what are hormones ? (2)

Answer 2

chemical messengers sent through the blood stream

bind to specific hormone receptors to exert their effect

Question 3

what is blood hormone concentration?

Answer 3

effect of hormone on tissue determined by the plasma concentration and number of active receptors

Question 4

what is plasma concentration determined by?

Answer 4

rate of secretion of hormone

rate of metabolism/excretion

quantity of transport proteins

changes in plasma volume

Question 5

how does the rate of secretion of the hormone effect plasma concentration?

Answer 5

magnitude of stimulatory input

stimulatory vs input

Question 6

how does the rate of metabolism/excretion effect plasma concentration?

Answer 6

blood flow during exercise to kidneys and liver

Question 7

how does the quantity of transport proteins effect plasma concentration?

Answer 7

steroid hormones are transported bound to plasma proteins

Question 8

how does changes in plasma volume effect concentration?

Answer 8

high intensity exercise decreases volume due to decreased water content, which increases hormone concentration

Question 9

what does the magnitude of effect of the hormone depend upon ? (3)

Answer 9

concentration of the hormone

number of target receptors on the cell

affinity of the receptor for the hormone

Question 10

what is meant by down regulation ?

Answer 10

decrease in receptor number in response to high concentration of hormone

Question 11

what is meant by up regulation ?

Answer 11

increase in receptor number ins response to low concentration of hormone

Question 12

what are the 3 mechanisms of hormone action? (3)

Answer 12

activation of genes to alter protein synthesis

activating second messengers in the cell via G proteins

altering membrane transport

Question 13

what is the mechanism of steroid hormone action ? (5)

Answer 13

hormone must be free to interact with the receptor

able to diffuse easily through the membrane

binds to protein receptor in the cytoplasm

translocated to the nucleus to bind to elements related to DNA and regulation of mRNA

can increase/decrease protein synthesis

Question 14

what is the cyclic AMP second messenger mechanism ?? (6 :|)

Answer 14

some hormones can’t pass through membrane due to size

bind to receptor on the membrane

activates G protein

this activates adenylate cyclase causing ATP conversion to AMP

AMP acts as secondary messenger

this activates protein kinase-A

Question 15

what is the membrane transport mechanism e.g. insulin receptor ?? (4)

Answer 15

binds to membrane receptor

hormone effects carrier molecules near/in membrane

GLUT4 activated which translocates from cytoplasm to membrane allowing glucose into the cell

diffuses through which allows glycogen synthesis

Question 16

what is ADH ? (4)

Answer 16

antidiuretic hormone

secreted from posterior pituitary gland

reduces water loss to maintain plasma volume

favours reabsorption of water from kidney tubules to capillaries

Question 17

what is ADH release stimulated by ? (4)

Answer 17

high plasma osmolality

low plasma volume

Question 18

how does exercise effect ADH in the plasma ? (2)

Answer 18

strenuous exercise causes decrease in plasma volume and osmolality

plasma release favours conservation of water to maintain the plasma volume

Question 19

what is aldosterone?(2)

Answer 19

secreted from the adrenal cortex control of Na+ reabsorption and K+ secretion

regulation of blood volume and pressure

Question 20

what is aldosterone release stimulated by ?

Answer 20

increase in plasma K+ concentration - NEG FEEDBACK

decrease in plasma volume