Cardiovascular System Flashcards
Define cardiac output
The amount of blood ejected out of the heart per minute (Q = HR x SV)
What does the pulmonary circuit do?
Carries deoxygenated blood to the lungs & oxygenated blood back to the heart
What does the systemic circuit do?
Carries oxygenated blood to the body & deoxygenated blood back to the heart
Define stroke volume
the volume of blood ejected from the left ventricle per beat and occurs during ventricular systole
Why does heart rate increase just before exercise?
Anticipatory rise due to adrenaline release
Define heart rate
The numbers of beats per minute (measured in bpm)
What does myogenic mean?
It is the hearts capacity to generate it’s own electrical impulse
What does SA node stand for and where can it be found?
Sino-atrial node - located in the right atrial wall
What does the SA node do?
Generates the electrical impulse causing atria to contract
What does AV node stand for and what does it do?
Atrio-ventricular node: collects the impulse sent from the SA node and delays the impulse by 0.1 seconds
Why does the AV node delay the electrical impulse?
To allow both atria to finish contracting
After the AV node releases the electrical impulse, where does it travel next?
Down the Bundle of His
Where is the bundle of His located?
in the septum of the heart
What is cardiac diastole?
Relaxation of the cardiac muscle
What is cardiac systole?
Contraction of the cardiac muscle
What is the common way to calculate someone’s HRmax?
220 - age
What is venous return?
return of blood to the right atria through the veins
What is the difference between sub-maximal and maximal exercise?
Sub-max = lot to moderate intensity exercise below the anaerobic threshold
Maximal = high intensity exercise above the aerobic threshold
What is Starling’s law?
It shows how stroke volume is dependant upon venous return
What is an average HR at rest?
70-72 bpm
What is an average SV at rest?
70 ml
What is an average cardiac output at rest?
5 l/min
Where would you find the cardiac control centre (CCC)?
Medulla Oblongata in the brain
What are the 3 sources of information that determine the action of the cardiac control centre?
Chemoreceptors, proprioceptors and baroreceptors
How can you tell the difference between the sympathetic and parasympathetic nervous system?
Sympathetic = activated in response to exercise
Parasympathetic = activated during recovery from exercise
Which blood vessel has smooth muscle in it’s wall as well as pocket valves to prevent backflow?
Veins
What is blood pooling?
The accumulation of blood in the veins due to gravity and lack of venous return due to stopping exercise
How can an athlete prevent blood pooling?
Perform an active recovery
Describe the vascular shunt mechanism
- Control centres in the medulla oblongata detect changes due to exercise
- Activation of sympathetic nervous system
- Pre-capillary sphincters constrict to organs and dilate to working muscles
What part of the brain controls the vascular shunt mechanism?
Vasomotor Control Centre (VCC)
Where does the Vasomotor Control Centre receive information from?
Chemoreceptors and baroreceptors
