help!!! I can't find these answers anywhere!

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someone please help, I've searched all my books and the internet and I'm still confused! :(

Which rationale describes why the cusp valves are different from the valves at the pulmonary artery and aorta? Select all that apply.

A- Chordi tendoni are needed to prevent back flow of blood into the atria due to the level of pressure occurring during ventricular contraction

B- Cusp valves prevent back flow of blood by closing after "forward" pressure reduces during diastole

C- Valves are needed to keep blood flowing from low pressure to high pressure vessels attached to the heart

D- Valves are different because of the kind of blood that passes through their openings

Is it A and B??

Why do veins have valves when arteries don't? Select all that apply

A- Because blood flow accelerates in the venous system

B- Because blood flow slows in the venous system

C- To prevent back flow of blood as venous walls don't have smooth muscle like arteries

D- To prevent blood clots from developing in the lower extremities

I know it's B and C, but could D work too?

Which is the best explanation of why fetal heart rate is 120-160 beats per minute?

A- The smaller the mammal, the faster the heart beat

B- The fetus exists in a reduced oxygen level in the uterus, so the heart rate increases to meet oxygen demand

C- The conduction system of the heart is immature; therefore it is more prone to a faster rate than an adult

D- Because the fetus doesn't "breathe" in the uterus, its heart rate stabilizes to circulate blood

D??

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Do you have a recent A&P book? You might want to check out Marieb's book.

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Why do veins have valves when arteries don't? Select all that apply

I don't think D has anything to do with it because the majority of DVTs occur in the lower legs.

...where'd you get these questions from? I don't think they are very good.

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Specializes in Case Mgmt, Anesthesia, ICU, ER, Dialysis.

a- chordi tendoni are needed to prevent back flow of blood into the atria due to the level of pressure occurring during ventricular contraction

b- cusp valves prevent back flow of blood by closing after "forward" pressure reduces during diastole

c- valves are needed to keep blood flowing from low pressure to high pressure vessels attached to the heart

d- valves are different because of the kind of blood that passes through their openings

is it a and b??

yes, it is a and b. c is incorrect because the only transition from low to high pressure in regards to vessels in the heart is during left ventricular systole to the aorta. both the rv and la connections to pulmonary vasculature are part of the pulmonary vascular system, a low pressure system, with 1/10th the resistance of the systemic vasculature. i would have to assume they're trying to differentiate between oxygenated and deoxygenated blood for d, but oxygenation isn't a factor in blood's viscocity, so i'm not sure what they're going for there.

why do veins have valves when arteries don't? select all that apply

a- because blood flow accelerates in the venous system

b- because blood flow slows in the venous system

c- to prevent back flow of blood as venous walls don't have smooth muscle like arteries

d- to prevent blood clots from developing in the lower extremities

i know it's b and c, but could d work too?

don't be so sure about b. if you say that blood flow slows in the venous system, then how does the body maintain its' ~5 lpm cardiac output? what goes out must come in, and for the body to maintain a constant cardiac output, would it not stand to reason that it would need to come in at the same rate it goes out? sequestration of blood in the pulmonary vasculature notwithstanding, if the respiratory rate and tidal volume remain fairly constant, the rate of continuous blood return to the right atrium should be roughly equivalent to what's exiting the left ventricle during systole, especially when factored over a constant time frame, e.g. per minute.

c is correct.

d is not correct. it is an indirect benefit of valves in the venous system, but it is not the reason veins have valves when arteries don't.

which is the best explanation of why fetal heart rate is 120-160 beats per minute?

a- the smaller the mammal, the faster the heart beat

b- the fetus exists in a reduced oxygen level in the uterus, so the heart rate increases to meet oxygen demand

c- the conduction system of the heart is immature; therefore it is more prone to a faster rate than an adult

d- because the fetus doesn't "breathe" in the uterus, its heart rate stabilizes to circulate blood

d??

well, it's definitely not b or c. not sure about a...it's not an explination per se, so i wouldn't answer that.

d is the only one left, so if you have to go with one, try that. trying to reason through why, and the only thing i can come up with is the pulmonary sequestration of blood during the respiratory cycle. if you're missing the volume of blood that's involved in gas exchange during the respiration, it increases how rapidly blood is presented to the lv, via the fetal pulmonary bypass systems of the ductus arteriosus and foramen ovale.

more blood = increased stroke volume or increased heart rate.

since an increased stroke volume would necessitate a larger chamber size, an increased heart rate is the logical conclusion - there's not a lot of room in utero to increase chamber size, after all.

agree with the person who said these are not the greatest questions. is this for a pathophys class or fundamentals??

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Specializes in Case Mgmt, Anesthesia, ICU, ER, Dialysis.
do you have a recent a&p book? you might want to check out marieb's book.

elaine marieb does have a good book. i second the recommendation. rhoades and bell is good, guyton and hall is also decent.

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why do veins have valves when arteries don't? select all that apply

a- because blood flow accelerates in the venous system

b- because blood flow slows in the venous system

c- to prevent back flow of blood as venous walls don't have smooth muscle like arteries

d- to prevent blood clots from developing in the lower extremities

i know it's b and c, but could d work too?

don't be so sure about b. if you say that blood flow slows in the venous system, then how does the body maintain its' ~5 lpm cardiac output? what goes out must come in, and for the body to maintain a constant cardiac output, would it not stand to reason that it would need to come in at the same rate it goes out? sequestration of blood in the pulmonary vasculature notwithstanding, if the respiratory rate and tidal volume remain fairly constant, the rate of continuous blood return to the right atrium should be roughly equivalent to what's exiting the left ventricle during systole, especially when factored over a constant time frame, e.g. per minute.

c is correct.

d is not correct. it is an indirect benefit of valves in the venous system, but it is not the reason veins have valves when arteries don't.

thank you soo much!! :redbeathe

for this question, it says "select all that apply" which makes me think there's more than 1 answer? so b could be an answer too? since it's not a or d

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LoL, these questions look very familiar. I have the same exact questions! This is for nursing 119. Glad I found this thread as I had put a different answer on the fetal heart rate but I see what you are saying as making sense.

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Specializes in CTICU.

"Select all that apply" does NOT mean that there's more than one answer correct. It means there could be.

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LoL, these questions look very familiar. I have the same exact questions! This is for nursing 119. Glad I found this thread as I had put a different answer on the fetal heart rate but I see what you are saying as making sense.

i tried to PM you but it wont let me. are you going to put B for the vein/valve question or just C?

I thought blood flow slowed in veins so thats why they had valves...

ahh confusing

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Specializes in Medical and general practice now LTC.
i tried to PM you but it wont let me. are you going to put B for the vein/valve question or just C?

I thought blood flow slowed in veins so thats why they had valves...

ahh confusing

Site requiremetns are 15 or more posts to be able to send a pm. You can read any that are sent to you just not reply until 15 or more posts

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Specializes in Emergency Dept. Trauma. Pediatrics.
"Select all that apply" does NOT mean that there's more than one answer correct. It means there could be.

Thankfully this is soon changing, at least according to our teachers, our professors told us on their exams if it says more then one can apply then there is for sure more then one. They feel that it stumbles the student up to much to put that and then only have one. They also said that NCLEX was soon going this route as well. Which I think is great, especially if you have test anxiety, if you have 15 questions with one answer and then come to one that is a MACA question your brain tries to automatically convince you their is more then one.

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Im going with c

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