CV response to exercise

Question 1

define physical activity

Answer 1

any body movement

Question 2

define exercise

Answer 2

body movement that is planned, structured, repetitive; has goal to improve physical fitness

Question 3

define physical fitness

Answer 3

a set of attributes related to the ability to perform a skill

Question 4

what is VO2

Answer 4

oxygen consumption (ml/min)

Question 5

3 determinants of VO2

Answer 5

HR
SV
oxygen diff. between arterial & venous sides

Question 6

equation for VO2

Answer 6

VO2 = HR x SV x (aO2 - vO2)

Question 7

increase in exercise = _____ VO2

Answer 7

increases

Question 8

what is VO2 max (literal definition)

Answer 8

maximal oxygen consumption

(maximum of all 3 components of equation)

Question 9

what is VO2 max (overall definition)

Answer 9

maximal / optimal rate at which heart, lungs, & muscles can effectively use oxygen during exercise

Question 10

_____ can improve VO2 max

Answer 10

training

Question 11

3 factors that change VO2 (impact all determinants of VO2)

Answer 11

-CO
-sympathetic activity
-redistribution of blood flow to exercising muscle

Question 12

equation for CO

Answer 12

CO = HR x SV

Question 13

pathway symp/parasymp response to increase in exercise

Answer 13

exercise
->
increase symp / decrease parasymp
->
increase HR & SV
->
increase CO, increase VO2

Question 14

does HR or SV have a larger impact on CO

Answer 14

HR

Question 15

CO _____ with exercise in order to _____

Answer 15

CO increases
to deliver O2 to exercising muscle

Question 16

_____ SNS, _____ PNS = increase HR

Answer 16

increase SNS
decrease PNS

Question 17

2 reasons SV increases during exercise

Answer 17

-positive inotropic effect
(increased contractility = increased SV)
-increased EDV (bc of increased venous return)

Question 18

why does ESV decrease during exercise

Answer 18

less blood in chamber after each contraction (bc increased contractility- Frank Starling)

Question 19

increase venous return = _____ EDV = _____ SV = _____ CO

Answer 19

increase venous return

increase EDV
=
increase SV
=
increase CO

Question 20

3 reasons venous return increases during exercise

Answer 20

-skeletal muscle pump activity
-respiratory pump activity
-SNS-induced vasoconstriction (decreased compliance)

Question 21

normally:
increase SNS = _____ vasoconstriction, _____ TPR

Answer 21

increases vasoconstriction
increases TPR

Question 22

exercise:
increase SNS = _____ vasodilation, _____ TPR

Answer 22

induces vasodilation
unchanged TPR

Question 23

5 mechanisms of vasodilation / smooth muscle relaxation

Answer 23

-sheer stress
-prostacyclin / nitric oxide pathways
-increase [H+] (lower pH, increase CO2)
-functional sympatholysis
-epinephrine (stimulates beta2 receptors- induces vasodilation)

Question 24

what is functional sympatholysis

Answer 24

local vasodilators can ALSO block alpha1-adrenergic receptors (which normally constrict)

Question 25

increase in MAP during exercise is attributed to _____ & _____

Answer 25

increase in SBP increase in CO

Question 26

equation for MAP

Answer 26

MAP = CO x TPR

Question 27

_____ relay changes in MAP during exercise

Answer 27

arterial baroreceptor afferents

Question 28

increase in MAP = activity of baroreceptor firing normally vs activity of baroreceptor firing during exercise

Answer 28

normally: increase in MAP = increases baroreceptor firing exercise: increase in MAP = decreases baroreceptor firing

Question 29

increase in MAP pathway normally

Answer 29

Question 30

increase in MAP pathway during exercise

Answer 30

Question 31

why does exercise result in a decrease in baroreceptor activity even though MAP increases

Answer 31

exercise "resets" the baroreceptor reflex

Question 32

normal mechanism of MAP increase

Answer 32

MAP increases -> aortic baroreflex afferents increase firing / excite NTS -> suppresses RVLM -> suppresses SNS activity / outflow

Question 33

exercise mechanism of MAP increase

Answer 33

MAP increases -> aortic baroreflex afferents INHIBITED by muscle mechano- & metaboreflex afferents -> NTS inhibited -> RVLM no longer inhibited -> increases SNS activity / outflow

Question 34

during exercise, TPR _____

Answer 34

is unchanged (or slightly decreases)