PSC1002/L05 Cardiovascular System Flashcards
Give 2 functions of the CVS.
Controlled & continuous blood flow
Homeostasis
Describe the relative pressure in each side of the heart.
Left - high (systemic)
Right - low (pulmonary)
Which blood vessels carry blood away from the heart?
Aorta
Pulmonary artery
Which blood vessels carry blood towards the heart?
Vena cava
Pulmonary veins
What are the 4 valves in the heart?
AV right - tricuspid
AV left - mitral or bicuspid
Semilunar right - pulmonary
Left - aortic
What causes valves to open and close?
Pressure changes
Define stroke volume.
Volume of blood pumped by one ventricle (75ml at rest)
Define cardiac output. (2)
Total volume of blood pumped per ventricle per minute
Depends on heart rate
What is the equation for cardiac output?
CO = SV x HR
Define venous return.
Amount of blood returning to the heart
Under steady-state conditions, what is the relationship between VR and CO?
VR = CO
Describe arteries (3)
High pressure
Elastic
For distribution
Describe arterioles. (2)
High resistance
Control of blood flow to tissues
Describe capillaries. (3)
Thin-walled
Arranged in parallel
For exchange
Describe veins. (3)
Low pressure
Capacitance vessels
For collection & storage
What is the equation for pressure gradient?
P1 - P2 = Delta(P)
How is pressure gradient created? (2)
Setup by heart acting as pump
Energy required to maintain
Why does the pressure of a fluid in motion decrease with distance?
Friction
What is the equation for pulse pressure?
PP = SP - DP
What is mean arterial blood pressure?
Pressure averaged over time
What is blood flow proportional to?
1/resistance
What is Darcy’s Law?
Flow = Delta(P)/R
What parameters determine resistance? (3)
Length of blood vessels
Radius of vessel
Viscosity of blood
What is the difference between blood flow and blood velocity?
Blood flow is volume per minute
Blood velocity is distance travelled per minute
