Basics 3

Question 1

how does the body meet the challenge of increased energy demand during exercise

Answer 1

hormones
- fuel mobilization
- delivery
-fuel utilization
- maintenance

Question 2

where does fuel (substrate) mobilization occur

Answer 2

liver, muscle, adipose

Question 3

what hormones are associated with fuel mobilization

Answer 3

• norepi
  -epi
  -glucagon
  -insulin

Question 4

what are the two main catecholamine forms and how are they released

Answer 4

Norepi = released from sympathetic nervous system

epi = adrenal medulla: released stimulated by NE

Question 5

what happens to the catecholamines during exercise

Answer 5

= exponential increase in circulating levels
= norepinephrine circulates at much higher levels

Question 6

what effect does exercise have on catecholamine response and why?

Answer 6

it blunts the response as a trained individual because more accustomed to the physical stress

Question 7

what do catecholamines do at the level of the liver

Answer 7

increase HGP
- increase glycogenolysis (first)
- increase gluconeogenesis (need to wait for available non-glucose sources)

Question 8

In a mice study why is liver sensitivity to epi/norepi reduced by training

Answer 8

• liver are less responsive to EP in trained mice as it is trying to preserve the limited stores in the liver

Question 9

What occurs at the level of adipose tissue in response to catecholamines

Answer 9

Lipolysis occurs which is the breakdown of TG to FA and glycerol

Question 10

what are the three lipase

Answer 10

adipose TG lipase
hormone sensitive lipase
monoglyceride lipase

Question 11

what effect does exercise have on lipolysis

Answer 11

increase (even in walking)

Question 12

what fates do fatty acids have after lipolysis

Answer 12

• oxidized within adipose tissue (<1%)
• released to circulation (60%)
• re-esterified within adipose tissue (40%)

Question 13

what does the increase in lipolysis do

Answer 13

activates hormone sensitive lipase in the adipose; FA is released
- mainly due to epi (B2 receptors)

Question 14

T or F responsiveness is greater in trained individuals for catecholamines at the level of the adipose tissue

Answer 14

true

Question 15

what increases due to catecholamines at the level of the skeletal muscle

Answer 15

increased muscle glycogenolysis
- activates glycogen phosphorylase (breakdown of glycogen)

Question 16

T or F the muscle can share its glucose stores (released into circulation)

Answer 16

false it is selfish and can only be used by the muscle it was held in

Question 17

where is glucagon released from and what does it counter act

Answer 17

alpha cells in the pancreas
counter-hormone to insulin

Question 18

what does glucagon do during exercise

Answer 18

increases as it responds to SNS activation

Question 19

what does glucagon stimulate

Answer 19

Hepatic glycogenolysis and gluconeogenesis
- some stimulation of adipose lipolysis

Question 20

what happens to insulin during exercise

Answer 20

it decreases early as epi and catecholamines reduce insulin secreetion

Question 21

does insulin decrease less or more frequently in trained individuals

Answer 21

more rapidly

Question 22

what does insulin inhibit

Answer 22

• HGP
• lipolysis

Question 23

what 3 hormones play a role in substrate delivery

Answer 23

NE
EPI
insulin

Question 24

equation for delivery of substrate =

Answer 24

concentration x blood flow

Question 25

cardiac out put (Q) =

Answer 25

HR x SV

Question 26

what is the main regulator of Q during exercise

Answer 26

neural input (central drive + joint feedback)

Question 27

what can catecholamines still do in regulation of Q

Answer 27

increase HR increase force of myocardial contraction (SV) cause vasoconstriction at non working muscles to divert blood

Question 28

main hormone for substrate uptake

Answer 28

insulin

Question 29

what does insulin stimulate in relation to substrate uptake

Answer 29

GLUT4 and FA transporter movement to the plasma membrane

Question 30

what other effects does insulin have on substrate uptake

Answer 30

activates pyruvate dehydrogenase to increase glucose oxidation acts as a vasodilator to increase blood supply

Question 31

where are most of insulins beneficial effects occurring

Answer 31

at the muscle where local factors are likely more important (regulating metabolism and opening capillary beds)

Question 32

difference in metabolism and blood flow in relation to insulin

Answer 32

M = decrease ATP, increase ADP and Pi; increase Ca2+ BF = increase in H+, K+, CO2 and nitric oxide

Question 33

_____ blood flow to the ______ muscle ________ insulin delivery to muscle and thus compensates for the _______ plasma insulin concentration

Answer 33

increased, contracting, increases, decrease

Question 34

what does the study show on acute exercise activation of muscle glucose uptake between obese and lean rats

Answer 34

in obese, insulin fails to stimulate plasma membrane GLUT4 accumulation - however, the ability for exercise to drive GLUT4 accumulation is identical for lean and obese rats - showing separate pathways (contracting muscles are able to up take glucose disregarding impaired glucose)

Question 35

what are the two hormones responsible for maintenance of Temp + fluid balance

Answer 35

catecholamines and renin axis

Question 36

does plasma vol increase or decrease during exercise

Answer 36

decrease (we sweat)

Question 37

what do catecholamines do in regard to maintenance

Answer 37

stimulate sweat production and renin production (maintains plasma volume and blood pressure) also reduces blood flow to skin (redirect) impairing heat dissipation

Question 38

what does renin, aldosterone, antidiuretic hormone all do to help maintain temp and fluid balance

Answer 38

all increase during exercise act to conserve sodium and water to maintain or blunt decrease in plasma volume allowing us to maintain BP

Question 39

what factors influence vessel dilation and constriction

Answer 39

SNS and local metabolites

Question 40

how does SNS influence Blood flow

Answer 40

constricts in most vascular beds (adrenergic)

Question 41

how do local metabolites change blood flow

Answer 41

dilating vessels of working muscles - increase in H+, lactate, potassium, CO2, etc. all indicate metabolic stress to the muscle

Question 42

mean arterial pressure =

Answer 42

TPR x Q

Question 43

why doesn't MAP increase more during exercise

Answer 43

large decreases in TPR due to dilation of working muscles (prevents dangerous increases in BP)