Physio exam review Flashcards
What is the consequence of a septal defect between the L and R ventricles?
Blood flow from L to R because the L ventricle is under much greater pressure than the right.
What is the difference in pressure between the L and R atria?
Zero. If there is a septal defect in the atria, there is no blood flow between the two chambers.
What prevents the mitral and tricuspid valves from everting to lower pressure regions in the atria during ventricular systole?
Chordae tenineae
Which has a greater volume, the right or the left heart?
They are equal
What is the pressure in the left atrium while standing?
Sub-atmospheric, -2 to -4 atm. This makes it easy for blood to return from the lungs to the heart.
Which muscles in the heart keep the valves from everting?
The papillary muscles prevent eversion in conjunction with the chordae tendineae.
What prevents mitral regurgitation?
Chordae tendineae
What is the ultimate fate of the valve leaflets after a myocardial infarction?
A myocardial infarction causes dilation of the heart muscles (they become loose), which increases their size. However, the leaflets remain the same size and, therefore, regurgitation occurs.
What is the most posterior structure in the heart?
Left atrium
What makes up most of the anterior surface of the heart?
Right ventricle
What other vessels following the aortic valve would be compromised in the case of a clogged aortic valve?
Coronary arteries –> They supply blood to the myocardium.
Which valves are larger and why? The AV valves, or the aortic and pulmonary valves?
The AV valves are larger. The aortic and pulmonary are smaller because they are send the same volume of blood through a smaller opening and thus achieving a greater velocity.
Give the relative percentages of blood output to organs
Renal 25%, GI 25%, Muscles 25%, Cerebral 15%, Coronary 5%, and skin 5%.
Why does the brain require such a relatively high percentage of cardiac output?
Because it does not store glucose and needs a continuous flow.
Do arteries have valves? Veins?
Arteries NO. Veins YES, one-way valves.
Where is blood found at its highest velocity?
Aorta
Which blood vessels have the greatest surface areas?
Capillaries
Which blood vessels hold the greatest volume of blood?
Veins, 2/3
Which blood vessels exert the greatest control of BP? Why?
Arterioles, because they display the greatest change in size. Capillaries don’t change size, arteries don’t change size, veins change SLIGHTLY, but not as much as arterioles.
Through which blood vessels does the greatest drop in blood pressure occur?
Arterioles.
What is the only part of the vasculature that moves? What receptors mediate this movement?
Arterioles. Alpha-1 receptors constrict, Beta-2 receptors dilate.
If the pressure can be dropped at the ____ of a system, the total flow will go up.
At the END of a system –> Blood flow = (Arterial pressure - VENOUS PRESSURE)/Vascular resistance. NOTE how increasing the pressure at the beginning of the system WITHOUT reducing the end pressure will DECREASE TOTAL FLOW.
What is the range of cycles per second the human voice is capable of, in Hz?
300-
Define autoreceptor and what they do
Alpha 2 receptors on the sympathetic postganglionic nerve terminals. They are activated by norepinephrine from presynaptic nerve terminals and INHIBIT FURTHER RELEASE of norepinephrine from the SAME TERMINAL.