Chapter 5: Hormonal Responses to Exercise

Question 1

GH location of synthesis

Answer 1

anterior pituitary

Question 2

stimulus for GH release

Answer 2

*exercise, sleep, stress, low BG

Question 3

actions of GH

Answer 3

anabolic hormone, promotes muscle hypertrophy

Question 4

how does GH change for prolonged exercise? graded exercise?

Answer 4

increased duration increases GH, increased intensity increases GH

Question 5

catecholamines site of synthesis

Answer 5

adrenal medulla

Question 6

stimulus for catecholamine release

Answer 6

flight or fight response

Question 7

how does catecholamine levels change for prolonged exercise? graded exercise?

Answer 7

increased duration increases NE & Epi, increased intensity increases NE & Epi

Question 8

how do levels of NE and Epi change with training?

Answer 8

NE & Epi decrease at the same given work rate with training

Question 9

cortisol location of synthesis

Answer 9

adrenal cortex

Question 10

stimulus for cortisol release

Answer 10

*exercise, stress, bone breaks

Question 11

how do cortisol levels change with exercise?

Answer 11

increased intensity increases cortisol levels

Question 12

glucagon site of synthesis

Answer 12

pancreas

Question 13

stimulus for glucagon release

Answer 13

decreased BG

Question 14

how do blood glucagon levels differ for trained and untrained athletes during prolonged exercise?

Answer 14

untrained individuals see a larger percent increase in glucagon levels (using more glycogen) whereas trained individuals do not see a percent increase in glucagon levels over time at the same intensity

Question 15

insulin site of synthesis

Answer 15

pancreas

Question 16

stimulus for insulin release

Answer 16

increased BG

Question 17

how do NE and Epi affect the hormones secreted by the pancreas?

Answer 17

stimulate glucagon secretion and inhibit insulin secretion

Question 18

how do insulin levels change with prolonged exercise? graded exercise?

Answer 18

increased duration decreases insulin, increased intensity decrease insulin

Question 19

which hormones increase circulating BG

Answer 19

glucagon, GH, cortisol, NE/Epi

Question 20

adequate glucose during exercise requires:

Answer 20

1) glucose release by the liver
2) glucose uptake by muscles

Question 21

actions of catecholamines

Answer 21

1) increase glycogenolysis at the liver & muscle (muscle glycogen used first) via B1 ADR
3) stimulates glucagon release and inhibits insulin release
2) increase lipolysis in adipose tissue

Question 22

actions of glucagon

Answer 22

1) increases glycogenolysis and gluconeogenesis at the liver
2) lipolysis in adipose tissue

Question 23

actions of GH

Answer 23

1) gluconeogenesis in liver
2) lipolysis in adipose tissue

Question 24

actions of cortisol

Answer 24

1) gluconeogenesis in the liver
2) lipolysis in adipose tissue

Question 25

how does glucose uptake remain high during exercise with lower insulin levels?

Answer 25

cellular insulin sensitivity is increased & there is increased blood flow and increased insulin delivery to active muscles despite lower concentration

Question 26

actions of insulin

Answer 26

1) stimulates glucose uptake in muscle cells via translocating GLUT4 transporters

Question 27

how does exercise increase glucose uptake independently of insulin?

Answer 27

exercise (contractions of muscles) translocate GLUT4 transporters to the membrane

Question 28

what 4 factors drive fat utilization down as exercise intensity increases (even though hormones are increasing lipolysis)

Answer 28

1) elevated H+ concentration inhibits hormone sensitive lipase (needed for fat mobilization)
2) high levels of lactic acid promotes resynthesis of triglycerides
3) inadequate blood flow to adipose tissue
4) insufficient albumin to transport FFA in plasma

Question 29

how does plasma volume change with exercise?

Answer 29

increased hydrostatic pressure (BP) –> fluid push out into interstitial space (+ water loss via sweating) –> decreased blood volume & decreased blood pressure –> increases heart strain

Question 30

vasopressin site of synthesis

Answer 30

hypothalamus

Question 31

stimulus for vasopressin release

Answer 31

decreased plasma volume or decreased MAP

Question 32

actions of vasopressin

Answer 32

increases water absorption by kidneys by inserting aquaporins into the membrane

Question 33

how does vasopressin change with exercise?

Answer 33

increased exercise intensity increases vasopressin

Question 34

aldosterone site of synthesis

Answer 34

adrenal cortex

Question 35

stimulus for aldosterone release

Answer 35

decreased plasma volume

Question 36

actions of aldosterone

Answer 36

increases Na+ and decreases K+ reabsorption in kidney, which causes water to follow the Na+

Question 37

how do aldosterone levels change with exercise?

Answer 37

aldosterone increases with exercise

Question 38

why does plasma volume continue to decrease with exercise even though vasopressin and aldosterone increase?

Answer 38

these hormones act at the kidneys, which receive decreased blood flow during exercise

Question 39

which is used first, muscle glycogen or liver glycogen?

Answer 39

muscle glycogen

Question 40

does blood glucose concentration change significantly during exercise?

Answer 40

no, because we are inhibiting glucose uptake in some areas (& promoting glycogenolysis and gluconeogenesis) but we are promoting glucose uptake at the active tissues

Question 41

why is there only a decrease in FFA mobilization during high intensity exercises rather than longer duration exercises?

Answer 41

factors such as H+ levels, lactic lacid, and insufficient albumin aren’t an issue in steady state exercise