CNS + CV control during exercise - week 3 Flashcards
what is the cardiovascular control centre ?
medulla oblongata
what does the medulla oblongata do ?
activates para vagus nerve which connects to SA and AV node
what does the parasympathetic NS do interns of the heart ?
calms down the heart
reduces signalling from SA node
what withdraws in the initial inset of exercise ?
parasympathetic system/signalling
what is end-diastolic volume ?
volume of blood in ventricles at end of diastole ‘preload’
what is aortic blood pressure?
pressure heart must pump against to eject blood ‘afterload’
during exercise ___ system kicks in , increasing ___ ___ which reduces ___ on the heart for those with hypertension
sympathetic
stroke volume
pressure
greater end diastolic volume results in ?
more forceful contraction
what factors influence venous return ? (3)
venoconstriction
skeletal muscle pump
respiratory pump
how do skeletal muscle pump effect venous control ?
rhythmic contractions of muscle force blood towards the heart
one way valves prevent back flow
how does the respiratory pump effect venous return ? (3)
changes in thoracic pressure pull blood toward heart
pull blood from lower extremities to heart
changes in respiratory rate increase venous return during exercise
what factors regulate cardiac output ? (5)
symp/parasymp
SA node increasing HR
stroke volume
end-diastolic volume
contraction strength
what is systolic pressure?
pressure generate during ventricular contraction
(higher number )
what is diastolic pressure ?
pressure in arteries during cardiac relaxation
What is pulse pressure ?
Difference between systolic and diastolic
What is mean arterial pressure ?
Average pressure in the arteries
What is the equation for cardiac output ?
CO= stroke volume x HR
Give an equation for MAP
MAP= CO x total vascular resistance
What are short term regulators of MAP? (3/4)
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
What are 2 changes to CV variables during exercise ?
Increased cardiac output
Redistribution of blood flow to working skeletal muscles
What do changes to HR and BP depend on during exercise ? (3)
Type, duration and intensity
Environmental conditions
Emotional influence pre and during submax exercise
State the changes that occur from rest to onset of exercise (3)
Rapid increase in HR, SV and CO
Plateau in submax exercise
Parasymp withdrawal
State the changes from exercise to recovery (2)
Decrease in HR, SV and CO to resting levels
Parasymp takes over, symp withdrawal
What’s the relationship between HR and CO with incremental exercise ? (3)
Increase linearly with increasing work rate
Directly proportional to O2 intake
Reaches plateau at 100% VO2 max
What’s the relationship between BP and incremental exercise ? (3)
MAP increases linearly
Systolic BP increases (contractility of heart)
diastolic BP remains constant
What occurs during a prolonged exercise at constant work rate ? (2)
CO is maintained
Gradual decrease in SV due to dehydration and reduced plasma volume
