CNS + CV control during exercise - week 3

Question 1

what is the cardiovascular control centre ?

Answer 1

medulla oblongata

Question 2

what does the medulla oblongata do ?

Answer 2

activates para vagus nerve which connects to SA and AV node

Question 3

what does the parasympathetic NS do interns of the heart ?

Answer 3

calms down the heart

reduces signalling from SA node

Question 4

what withdraws in the initial inset of exercise ?

Answer 4

parasympathetic system/signalling

Question 5

what is end-diastolic volume ?

Answer 5

volume of blood in ventricles at end of diastole ‘preload’

Question 6

what is aortic blood pressure?

Answer 6

pressure heart must pump against to eject blood ‘afterload’

Question 7

during exercise ___ system kicks in , increasing ___ ___ which reduces ___ on the heart for those with hypertension

Answer 7

sympathetic

stroke volume

pressure

Question 8

greater end diastolic volume results in ?

Answer 8

more forceful contraction

Question 9

what factors influence venous return ? (3)

Answer 9

venoconstriction

skeletal muscle pump

respiratory pump

Question 10

how do skeletal muscle pump effect venous control ?

Answer 10

rhythmic contractions of muscle force blood towards the heart

one way valves prevent back flow

Question 11

how does the respiratory pump effect venous return ? (3)

Answer 11

changes in thoracic pressure pull blood toward heart

pull blood from lower extremities to heart

changes in respiratory rate increase venous return during exercise

Question 12

what factors regulate cardiac output ? (5)

Answer 12

symp/parasymp

SA node increasing HR

stroke volume

end-diastolic volume

contraction strength

Question 13

what is systolic pressure?

Answer 13

pressure generate during ventricular contraction

(higher number )

Question 14

what is diastolic pressure ?

Answer 14

pressure in arteries during cardiac relaxation

Question 15

What is pulse pressure ?

Answer 15

Difference between systolic and diastolic

Question 16

What is mean arterial pressure ?

Answer 16

Average pressure in the arteries

Question 17

What is the equation for cardiac output ?

Answer 17

CO= stroke volume x HR

Question 18

Give an equation for MAP

Answer 18

MAP= CO x total vascular resistance

Question 19

What are short term regulators of MAP? (3/4)

Answer 19

Baroreceptors

Increase in BP = decrease SNS activity
Decrease in BP = increase in SNS activity

Low BP causes less baroreceptor signals to brain so body increases BP

Question 20

What are 2 changes to CV variables during exercise ?

Answer 20

Increased cardiac output

Redistribution of blood flow to working skeletal muscles

Question 21

What do changes to HR and BP depend on during exercise ? (3)

Answer 21

Type, duration and intensity

Environmental conditions

Emotional influence pre and during submax exercise

Question 22

State the changes that occur from rest to onset of exercise (3)

Answer 22

Rapid increase in HR, SV and CO

Plateau in submax exercise

Parasymp withdrawal

Question 23

State the changes from exercise to recovery (2)

Answer 23

Decrease in HR, SV and CO to resting levels

Parasymp takes over, symp withdrawal

Question 24

What’s the relationship between HR and CO with incremental exercise ? (3)

Answer 24

Increase linearly with increasing work rate

Directly proportional to O2 intake

Reaches plateau at 100% VO2 max

Question 25

What’s the relationship between BP and incremental exercise ? (3)

Answer 25

MAP increases linearly

Systolic BP increases (contractility of heart)

diastolic BP remains constant

Question 26

What occurs during a prolonged exercise at constant work rate ? (2)

Answer 26

CO is maintained

Gradual decrease in SV due to dehydration and reduced plasma volume