Cardio 2 Flashcards
How does the pericardium help with pumping?
It helps distribute pressures around the heart –> increases efficiency of the pumping
What’s the maximum number of chambers in the heart in any species?
Four
What is the function of the papillary muscles?
To prevent eversion of the atrioventricular valves (prevent backward flow)
Conduit
transport rapidly at high pressure (arteries)
Capacitance
transport slowly at low pressure, for storage (veins)
Do veins have valves?
Some present in larger veins (make sure flow is unidirectional)
Component of the circulatory system with highest cross-sectional area?
Capillaries
What does compliant mean?
Easily distendable with no pressure
Compliance = change in volume divided by change in pressure
Are arteries compliant?
No, very stiff, thicker walls
Are veins compliant?
Yes, thinner walls, lower pressure
If you appply pressure to arteries, what is the maximum increase in blood volume you might see?
10%
What component of the systemic circulation holds the most blood?
Venules and veins
What component of the systemic circulation has the highest flow velocity?
Arteries
Perfusion pressure
Difference between the pressure at the inlet and the outlet
Transmural pressure
Difference between the pressure inside and outside the vessel
Units of pressure
mm Hg
Systole
Contraction, blood leaving the heart
Diastole
rest (not contracting)
Why does your systolic blood pressure increase as you age?
Arteries become less elastic, so the pressure wave from the arterioles is reflected back earlier
What happens to blood pressure as you get further away from the heart?
Systolic pressure increases
Mean and diastolic pressure decrease
Highest mean pressure in systemic circulation?
Ascending aorta
Lowest mean pressure in systemic circulation?
Right atrium
What’s the purpose of blood flow through the lungs?
Oxygenate the blood and dispose of carbon dioxide (flow more important than pressure)
Windkessel Effect of the Aorta
The most proximal part of the aorta has a lot of elastin; when blood is ejected from the LV, some will expand the aorta, then when the aortic valve shuts that volume will create more [continous] flow
Aortic Aneurysm
weakening of arota over time leads to tears, blood fills around the heart and then you die
