Overview of the function of the CVS1 and CVS2 Flashcards
What does cardiovascular system transport?
O2 and CO2
Nutrients
Metabolites
Hormones
Heat
What side of heart pumps blood into pulmonary circulation?
right side of heart
What side of heart is responsible for pumping blood into the systemic circulation?
left side
How is the cardiovascular system flexible?
Pump can vary output
Vessels can redirect blood
Vessels can store blood
Describe why pumps of heart are in series?
in parallel
output is equal and tissues don’t receive deoxygenated blood
Describe how vascular beds are arranged?
in parallel
Allows regional redirection of blood
e.g. in exercise want more blood going to skeletal muscle
Why are gut and liver in series?
so nutrients in gut to be metabolised in liver
What is the name of the liver’s own blood supply that’s arranged in parallel?
portal system
Why does skin receive 9% of total output but only using 2% of oxygen?
more blood to skin so heat can be lost from it
Why do kidneys receive 20% output but only use 6% oxygen?
kidneys are acting as filter
Why does heart receive 4% of cardiac output but uses 10% of oxygen?
What is darcy’s law?
flow= difference in pressure/ resistance
What is meant by pressure difference?
mean arterial pressure (left hand side pressure)- central venous pressure (left hand side pressure)
Where is the higher pressure on sides of the heart?
high pressure on left- to pump blood to systemic circ
low pressure on right-to pump blood back to heart
How is resistance determined?
controlled by radius cubed
What acts ass taps in resistance?
arterioles
Difference between arteries and veins?
arteries - carry blood away from heart
veins - carry blood towards heart
Role of veins and venules?
capacitance vessels
blood storage
Veins and venules return blood to right side of heart
Describe the meaning of fractional distribution of blood?
the proportion of blood that is in veins and venules versus the rest of your systemic circulation
Features of aorta?
blood leaves heart from left side here
Elastic arteries
Wide lumen ( low resistance for blood to flow very easily from left ventricle into aorta and off to systemic circulation)
Thick elastic wall
Damp pressure variations
What are the two elastic arteries in your body?
aorta and pulmonary trunk
Features of arteries?
Muscular arteries
Wide lumen
Strong, thick, non-elastic wall
Low resistance conduit
Features of arterioles?
Resistance vessels
Narrow lumen
Thick contractile wall
Control resistance and therefore flow
Allow regional redirection of blood
Give features of capillaries?
Exchange vessels
Narrow lumen
Thin wall
Give features of venules?
Capacitance vessels (2/3 body’s blood)
Wide lumen
Thin, distensible wall
Low resistance conduit and reservoir
Allows fractional distribution of blood between veins and rest of circulation
Blood flow?
blood is squeezed from the left ventricle out into the aorta
aorta is an elastic artery and so during that ejection phase - the wall of aorta stretches out
the blood will pass into muscular arteries and then into arterioles
after arterioles, blood passes into very small capillaries
deoxygenated blood returns to RHS of heart via veins and venules
Pumps of heart?
pump on right- pumps to pulmonary circulation
pump on left- pumps blood into systemic circulation
Through what does deoxygenated blood return to right atrium through?
through the vena cava
Functions of superior and inferior vena cava?
superior- returns blood from part of body above heart
inferior - below heart
How is deoxygenated blood pumped into pulmonary circulation?
deoxygenated blood will fill into the right ventricle then into pulmonary trunk- which bifurcates into a left and right pulmonary artery - where it’s then pumped into pulmonary circulation.
When blood has been oxygenated, it returns to the left atrium via the pulmonary veins.
Oxygenated blood will then fill into the left ventricle and it will be pumped out into the aorta to go round the body again.
What is the valve between the left ventricle and the aorta?
aortic valve
What is the valve between the right ventricle and the pulmonary trunk?
pulmonary valve
When are valves open and closed?
open when heart is in systole - blood squeezed out of ventricles unto aorta and pulmonary trunk
closed when heart is in diastole- when heart chambers are filling up with blood
Where is the tricuspid valve?
between right atrium and right ventricle
Where is the mitral valve?
between LA and RV
-only two cusps
What are the jobs of the mitral and tricuspid valves?
to prevent regurgitation of blood from the ventricle back into the atrium
What are chordae tendinae attached to?
papillary muscles- contract at same time as ventricles
How do the valves open and close?
due to changes in pressure in heart.
The chordae tendinae and papillary muscles are only there to stop valves from turning inside out
