comparison of lymph and veins

[UIUCstudent]

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So just need some clarification on this comparison.

Lymph system are similar to veins, in that flow is caused by skeletal muscles squeezing the vessels and the flow is in one direction because of semilunar valves. Are there any other forces that cause this movement?

Vasoconstriction can occur by the smooth muscles surronding the lacteal and vein vessels.

 

[jphwki82]

So just need some clarification on this comparison.

Lymph system are similar to veins, in that flow is caused by skeletal muscles squeezing the vessels and the flow is in one direction because of semilunar valves. Are there any other forces that cause this movement?

Vasoconstriction can occur by the smooth muscles surronding the lacteal and vein vessels.

The lymphatic vessels will spontaneously contract. Other things contributing to the flow of lymph consist of its valves, compression during skeletal muscle contraction and arterial pulsation.

 

[UIUCstudent]

The lymphatic vessels have smooth muscle, which will undergo peristalsis. Other things contributing to the flow of lymph consist of its valves, compression during skeletal muscle contraction and arterial pulsation.

Sweet. I wonder how arterial pulsation factors in?

This contradicts a passage I had though.

What force moves the lymph inside the lymphatic vessels?
I. Squeezing by the muscles.
II. Contraction of the muscular layer of the lymph vessels.
III. Blood Pressure.

A. I only
B. I and II only
C. II and III only
D. I, II, and III

Correct answer was A. I don't think I'll dwell too much on this question b/c the wording seems vague. Choice I. doesn't specify that it is the skeletal muscle, yet the answer key mentions that's what it was referring to in the back.

 

[jphwki82]

Sweet. I wonder how arterial pulsation factors in?

This contradicts a passage I had though.

What force moves the lymph inside the lymphatic vessels?
I. Squeezing by the muscles.
II. Contraction of the muscular layer of the lymph vessels.
III. Blood Pressure.

A. I only
B. I and II only
C. II and III only
D. I, II, and III

Correct answer was A. I don't think I'll dwell too much on this question b/c the wording seems vague. Choice I. doesn't specify that it is the skeletal muscle, yet the answer key mentions that's what it was referring to in the back.

I went to check out my old MCAT prep book to confer what they expect you to know for MCAT purposes. To simplify things for the MCAT purposes, they main means lymph flow is accomplished is via rhythmic contraction of the lymph vessels and by contraction of skeletal muscles. What prep book are you using? Also, was this question associated with a passage?

 

[UIUCstudent]

I went to check out my old MCAT prep book to confer what they expect you to know for MCAT purposes. To simplify things for the MCAT purposes, they main means lymph flow is accomplished is via rhythmic contraction of the lymph vessels and by contraction of skeletal muscles. What prep book are you using? Also, was this question associated with a passage?

Berkeley Review. The passage had a sentence that said the structure of the lymph vessel is similar to the vein. "the vein does not have a muscular layer like the artery. Choice II is incorrect. "

Still, peristalsis involves contraction of the muscle. I guess this is one of those questions you have to try to understand the author's intention behind the question.

 

[Rabolisk]

It appears that BR is wrong, although this is a very nit-picky topic. It appears that only some lymph vessels have the smooth muscular layer around them, and that overall, this is a minor factor in movement of the lymphatic system.