Intro To CVS (and Maths) Flashcards
What is the heart made of and encased in
Myometrium encased in pericardium
What are the 2 circulations called
1- systemic (oxygenated to body)
2- pulmonary (de oxygenated to lungs)
What are the 4 valves called
1- left AV/bicuspid/mitral
2- right AV/tricuspid
3- aorta valve / left semilunar
4- pulmonary valve / right semilunar
What is stroke volume
Volume of blood pumped out in ventricle
What is cardiac output
Volume of blood pumped out in 1 minute
How do you work out cardiac output
SV x heart rate
What is cardiac output from ventricles equal to in steady state
Venous return (blood returning)
Why do arteries have large muscle layer
For distribution to withstand high pressure
why do arterioles have the thickest muscle layer
To control blood flow into capillaries
What is capillaries job
Exchange of materials
Why don’t veins need thick muscle
Low pressure and stretch without changing pressure
Why is vein job called ‘storage’
Most of the blood in the body are in veins
What 2 variants affect blood flow rate
Pressure gradient and resistance
How do you work out pressure gradient
P1 - P2
Why does pressure decrease with distance
Friction
Which out of the 2 circulations is at highest pressure
Systemic circulation
What is the maximum pressure and minimum pressure Called in arteries
Max = systolic pressure
Min = diastolic pressure
How do you work out pulse pressure
Systolic pressure - diastolic pressure
What is MAP
Mean artery pressure overtime
How do you work out blood flow
Pressure gradient / resistance
How is resistance worked out
8Ln / pi r^4
L x viscosity / pi r^4
Which part of resistance equation varies
Radius
What happens if radius doubles
Resistance will decrease
Blood flow will increase
What is blood velocity
Distance travelled by blood in 1 minute
How is blood velocity worked out
Blood flow rate / cross sectional area
How do you work out cross sectional area
Pi r 2
What happens if a vessel has large cross section
The blood velocity decreases
Which vessel has largest cross section
Capillaries in a bed
Why is low blood velocity in capillaries good
Allows for effective exchange
