Exercise Physiology Flashcards Preview

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Flashcards in Exercise Physiology Deck (62):
1

What is the equation for SV?

SV = EDV - ESV

2

What is the equation for MAP?

CO x TPR

3

What is the equation for VO2?

CO x avO2 diff

4

What are the effects of the SNS with exercise?

Increases HR, contractility, and TPR

5

What is the limiting factor of exercise, normally?

cardiac output

6

What are the three factors of CO that the SNS affects?

HR
TPR
Contractility

7

Why does SNS activity increase with exercise?

Resetting the baroreflex set point to a higher pressure d/t changes in the central command and the exercise pressor reflex

8

How is the baroreceptor reflex controlled? (3)

-Mechanoreceptors in the heart
-central command
-Exercise pressor reflex

9

What are the two receptors that are responsible for baroreceptor resetting via the exercise pressor reflex?

Mechanoreceptors
Metaboreceptors

10

What is the feedforward mechanism of SNS?

Central command increases SNS

11

What is the feedback mechanism of the SNS during exercise?

Exercise pressor reflex

12

What is the effect of the SNS on nerve activity with a drop in arterial pressure? Sudden increase?

-Inhibit the vagus if drops
-Stimulate if increases

13

What happens to SNS activity with increased BP? When in the cardiac cycle do these bursts occurs?

Increased discharge

When pressure drops during diastole

14

Where does arterial constriction occur at to increase TPR? (3)

Skin
Muscle
Kidney

15

What is the central command bit of BP regulation? What does this do?

Higher CNS areas that operate in anticipatory phase of exercise and during exercise

Increases SNS output with increased alpha motor neuron output

16

What are the three areas that are affected with increased activity of "central command"?

Skeletal muscles
CV system
Respiratory system

17

What are the nerves that relay the exercise pressor reflex?

Grp III = mechanoreflex
Grp IV = Metaboreflex

18

What is the effector part of the exercise pressor reflex? What is the integration site?

SNS

CV centers

19

What are the two variables sensed with the exercise pressor reflex?

-Metaboreflex (VD metabolites)
-Mechanoreflex (speed and force of contraction)

20

What happens to the distribution of blood with increasing intensity of exercise?

Redistributes more to the muscles

21

What percent of flow can be redirected to muscle during exercise?

80%

22

What is the normal CO during rest? Exercise in an athlete?

5 L/min

40L/min in an athlete

23

What allows vasodilation of the muscles despite SNS activity telling it to constrict?

Metabolic autoregulation--accumulation of VD metabolites increase during exercise, causing vasodilation

24

What are the two places in the body that are not affected with constrictive SNS activity?

Brain
Coronary vasculature

25

What happens to SBP and DBP as exercise intensity increases?

-SBP increases
-DBP stays constant, or lowers

26

What causes the drop in DBP with exercise?

Muscular vasodilation causes a drop in TPR

27

SBP rises in proportion to what?

Flow

28

What happens to DBP with resistance exercises?

Increased TPR d/t resistance to flow in the muscles

29

What is the relative increase in BP and HR with arm exercise compared to leg? What is the significance of this?

Arm causes a higher increase in HR and BP

MIs frequently occur with arm exercise

30

What is the range of average VO2max?

30s, with higher being better

31

What is the VO2max that indicates difficulties with ADLs?

12-14 ml/kg*min

32

What are METs?

x resting VO2

33

What is the relation between HR and work rate?

Will increase in similar amounts.

34

What is the use of submaximal tests or walking tests?

Increase in distance for a 6 min walk test

measures improvement

35

What is the equation for VO2?

HR x SV x avgO2 diff

36

What causes the increase in HR with exercise?

Vagal withdrawal, increases in SNS

37

What is the max HR equation?

208- (0.7 x age)

38

Why does stroke volume increase with exercise? (3)

-Increased venous return
-SNA on cardiac muscle (Ca)
-Decreased TPR

39

What is the Ca induced Ca release model of cardiac myocytes?

Increase in Ca from SNS increase, increases contractility

40

What is avO2 difference?

Difference between the oxygen content in arterial blood and venous blood

41

Why does the avO2 difference increase with exercise? (2)

-Redistribution of flow to active tissues during exercise
-Rightward shift of oxyhemoglobin dissociation curve

42

What happens to the hypothalamic set point with increased heat with exercise?

No change in the set point, but still regulated

43

What is the compensatory response to increased heat generation? How?

Cutaneous vasodilation d/t dual innervation of the SNS

44

What are the four responses to cold?

-Cutaneous vasoconstriction
-Piloerection
-Shivering
-Increased thermogenesis

45

What are the two major responses to increased heat?

-Cutaneous vasodilation
-sweating and evaporation

46

True or false: skin competes with muscle for flow during exercise

True

47

What does it mean that skin is a compliant circulation?

Readily changes circulation with temperature changes

48

Why is heating a cardiac strain?

Blood is shunted into skin, meaning more CO is needed to maintain homeostasis

49

What happens to SV with prolonged sweating from exercise? How is this compensated for?

Drops d/t dehydration
Increases HR

50

What is the MOA of heat related stress problems?

Decreased SV causes problems if heart has issues increasing rates

51

What is phase I of integrated regulation during exercise?

Central command increases ventilatory rate

52

What is phase II of integrated regulation during exercise?

Ve rises to reach steady state

53

Lactate accumulation in exercise is due to what?

Inability to remove it

54

What is the LT?

Point at which lactate accumulates within the blood

55

What is the VT?

VE/VO2 relationship departs from linearity

56

What happens physiologically with exercise training?

Better at extracting the O2, so decreased muscle blood flow spares blood for thermoregulation

57

What are the metabolic adaptations to training? (5)

-Increased mitochondrial response
-Capillary density
-Glucose sparing effect
-Blood lactate clearance
-Insulin sensitivity

58

What are the GLUT transporters that are increased with exercise?

GLUT4

59

What does it mean that exercise is a natural insulin?

Will cause an increase in GLUT4

60

What are the two primary controllers of ventilatory rate?

CO2 and pH

61

What happens in phase III of ventilation during exercise?

Fine tuning through peripheral feedback

62

What happens in the recovery phase of ventilation regulation?

Abrupt loss of central command and peripheral muscle causes drop in ventilation