Cardiovascular System
A given arteriole has a resistance of 2. What would the new resistance of this vessel be if its radius were to double?
1/8 Resistance of a tube = (8*L*n)/(pi*r^4) R is proportional to 1/r^4 Ex: 2 = 1/r^4 ; R' = 1/(2r)^4 R' = 1/(2r)^4 --> 1/16 * 1/r^4 --> 1/16 * 2 = 1/8
what does vasoconstriction do?
decreases blood flow due to HIGH resistance and increases BP
what is the time between S2 and S1
diastole
what occurs when you hear the S2
dub = 2nd heart sound T&M open P&A close (semilunar valves close)
What layer of the heart would be most immediately susceptible to infections caused by bacteria circulating in the blood?
endocardium
layers of the heart
endocardium (closest to RBCs), myocardium (thick smooth muscle tissues), and epicardium (visceral closest to myocardium, gap, then parietal = outer layer)
Where do you expect to have the highest pressure (in regards to blood)?
exiting the heart via aorta
what does vasodilation mean?
increase blood flow due to LOW resistance and decreases BP
Which blood vessels is composed of elastic?
large/medium arteries in their tunica media (smooth muscle) remember: increase elastic = increaser pressure
Where does systemic circulation begin?
left ventricle --> aorta and end in the R atrium (carries oxygenated blood)
what occurs at the beginning of S1
lub = 1st heart sound T&M close (atrioventricular valves close) P&A open
where does the pulmonary circulation begin?
right ventricle --> lungs and end in the L atrium (carries deoxygenated blood)
what is the time between S1 and S2
systole
In terms of being open or closed, what is the state of the mitral and tricuspid valves (left and right atrioventricular valves, respectively) at the end of the first heart sound?
they are both closed
In terms of being open or closed, what is the state of the semilunar valves at the end of the second heart sound?
they are both closed
In terms of being open or closed, what is the state of the mitral and tricuspid valves (left and right atrioventricular valves, respectively) at the end of the second heart sound?
they are both open
In terms of being open or closed, what is the state of the semilunar valves at the end of the first heart sound?
they are both open
How can the circulatory system promote heat retention/conservation such as on a cold day?
vasoconstriction because vasoconstriction will reduce the amount of energy dissipated retaining it in the body on a cold day
How can the circulatory system promote heat retention/conservation such as on a hot day?
vasodilation because the arteriole's radius will increase due to less pressure/resistance and thus more energy will dissipate
Rank the following blood vessels in order of their average pressure, from highest to lowest: artery, vein, arteriole, venule, aorta, and capillary
H: aorta > artery > arteriole > capillary > venule > vein :L
Where does lymph tissue reenter cardiovascular system and why?
It enters just before the vena cava because these veins have low pressure of 5 mmHg making it ideal to reenter such high pressure system
At the instant following the second heart sound, which heart valves are open?
The 2nd heart sound = beginning of diastole which means the semilunar valves have closed and there is a brief period of isovolumetric relaxation prior to next heart sound
How does the tunica media differ between arteries and arterioles?
arteries have elastin in their smooth muscle whereas arterioles have thicker tunica media without elastin otherwise remaining layers are the similar
what blood vessels can regulate BP?
arterioles
