circulatory system

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?

Both are closed

At the instant following the second heart sound, which heart valves are open?

All valves are closed -this is considered the diastolic.

Rank the following blood vessels in order of their average pressure, from highest to lowest: artery, vein, arteriole, venule, aorta, capillary.

Aorta > artery > arteriole > capillary > venule > vein

What layer of the heart would be most immediately susceptible to infections caused by bacteria circulating in the blood?

Endocardium

What vessels carry deoxygenated blood away from the heart?

Pulmonary artery only

Which heart valves are NOT actively closed by the contraction of muscular structures?

Semilunar valves

What physical feature of large systemic arteries (resistance vessels) makes them relatively more responsive to changes in intracellular calcium concentrations?

Thick tunica media

How can the circulatory system promote heat retention/conservation, such as on a cold day?

Vasoconstriction -The circulatory system promotes heat retention/ conservation through vasoconstriction of vessels in the skin.

What is the correct path through the circulatory system which describes the passage of blood originating in the left leg?

Vena cava → right atrium → right ventricle → lungs → left atrium → left ventricle → aorta

A given arteriole has a resistance of 2. What would the new resistance of this vessel be if its radius were to double?

⅛ -Resistance in a tube is equal to (8*L*n)/(pi*r^4) where L is the length of the tube, n is the viscosity, and r is the radius.