2. basics cont. and endocrine system

Question 1

4 roles of hormones at the onset of exercise

Answer 1

1 - fuel mobalization (liver, adipose, muscle)
2 - delivery (cardiovascular)
3 - fuel utilization (skeletal muscle)
4 - maintenance of thermal/fluid regulation (cardiovascular, renal)

Question 2

role of insulin

Answer 2

substrate mobilization

stimulates
- glucose uptake into muscle

inhibits

• lipolysis (liver and adipose)
• hepatic glucose production

Question 3

what increases and decreases glucose release from liver

Answer 3

increase

• catecholamines
• glucagon
• cortisol

decrease
- insulin

Question 4

catecholamines

• release
• stimulation
• amount ratio

Answer 4

norepinephrine (NE)
- released from sympathetic nervous system (SNS)

epinephrine (EPI)

• adrenal medulla
• released stim by NE
• NE 7-fold higher than EPI
• EPI mainly produces the effect
• exponential increase with exercise

Question 5

catecholamines effect

- fuel mobilization

Answer 5

increase muscle glycogenolysis (glycogen breakdown)
- activates glycogen phosphorylase

induces GLUT4 translocation
- brings glucose into muscle

Question 6

one of the few hormones that decreases with exercise

Answer 6

insulin

• anabolic
• exercise is catabolic

Question 7

glucagon released from

Answer 7

pancreas

Question 8

role of glucagon

Answer 8

stimulates

• hepatic glucose production (gluconeogenesis)
• adipose tissue lipolysis (less important)
• counter hormone to insulin
• increases in response to exercise

Question 9

cortisol secreted from

Answer 9

adrenal cortex

Question 10

growth hormone secreted from

Answer 10

anterior pituitary

Question 11

role of cortisol and growth hormone

- response to exercise

Answer 11

increases with exercise

• possible role in stim lipolysis and hepatic glucose production
• importance not yet clear

Question 12

regulator of cardiac output during exercise

- which systems

Answer 12

main
- neural

others

• receptors in joints and muscle (act as accelerators)
• hormonal slower and less important

Question 13

catecholamines role during exercise

- delivery (cardiac output)

Answer 13

mostly NE

• increase HR
• increase stroke volume (increase force of myocardial contraction)
• vasoconstriction of non-muscle (skin, splanchnic bed, kidney) and non-working muscle
• diversion of cardiac output to where its needed

Question 14

insulin role

• substrate delivery
• why still decrease during exercise

Answer 14

stimulates glut4 and fat transporter movement to the plasma membrane
- increase glucose and FFA uptake into muscle

activates pyruvate dehydrogenase (PDH)
- increase glucose oxidation

acts as vasodilator
- increase blood supply

decrease during exercise*
- only want nutrient uptake by working muscle, not all tissues

Question 15

delivery of substrate calculation

- how insulin is effected

Answer 15

concentration x blood flow

insulin

• decreases concentration
• increases blood flow (vasodilation)
• less total insulin but more reaches working muscles for nutrient uptake

Question 16

catecholamines

- maintenance: temp and fluid balance

Answer 16

• reduce blood flow to skin (impairs heat dissipation* –> gets overridden)
• stimulates sweat production
• stimulates renin production (decreases plasma volume, manages blood pressure)

Question 17

renin secretion

Answer 17

kidney

- increase with exercise

Question 18

aldosterone secretion

Answer 18

adrenal

- increase with exercise

Question 19

antidiuretic hormone secretion

Answer 19

posterior pituitary

- increase with exercise

Question 20

renin, aldosterone and antidiuretic hormone

- function during exercise

Answer 20

increase with exercise

• conserve sodium and water to maintain/blunt the decrease in plasma volume (catecholamines cause decrease)
• regulate blood pressure

Question 21

role of hormones in exercise

Answer 21

minor effect muscle substrate utilization

HGP and adipose tissue lipolysis
- catecholamines, insulin, glucagon

*main effect "delivery" and "maintenance"
catecholamines
- direct away from non-working muscle
- increase cardiac output
- thermoregulation and fluid balance

Question 22

myokine

Answer 22

a cytokine

• protein involved in cell-cell communication
• released from muscle

ex. interleukin (IL-6)
- released by contracting muscle