Biology Questions and Answers
Only capillaries perform exchange of
gases and other substancestissues. with the
- Are the arteries or the
veins constituted of more
muscle tissue? How different
are the walls of these two
types of blood vessels?
The arterial system has thicker muscle
walls since within circulates under higher pressure. Thearteries the blood (^)
veins are more flaccid than arteries.
From the lumen to thboth types of vessels are e external laymade of er
endothelium, muscle tissue aconnective tissue. In both thend
endothelium is a singlarteries the muscle tissue pe layer ortion of cells. Inis
thicker than in veins and in these
vessels the external cothicker than in arteries.nnective tissue is
Arteries are the pulsating The arterial pulse can be felt in ablood vessels.
medical examination, for example, by
the palpation ointernal and lateral ff the radial artery in ace of the wristthe
near the base of the thumb.
- What are the valves of the
venous system? What is their
function?
The valves of the venous system are
structures iblood to flow only nside the veins that pin the normal wayermit
(from the tissues to the heart) and
forbid it to return in the reverse way in
favor of gravity. The valves close whenthe pressure of the fluid colum(after, regarding normal flux) is highern above (^)
than the fluid pressure before them.
Valves arreturning of blood to the thus fundamental for thee heart.
- How do the muscles of the
legs and of the feet contribute
to the venous return?
The musclesmuscles of the calves, contract of the legs, mainly the and
compress the impelling the blood to the heart.deep veins of the legs
The plantar pblood and when it is compresseortion of the feet retainsd against (^)
the ground it impels its blood volume
and aids venous return.
- What are varices? Why are
they more common in the
inferior limbs?
Varix means abnormal enlargement of
veins. Varicespressure against the normal bl occur when excessiveood flux (^)
creates enlargement of the vein and
thus insufficient fu(venous insufficiency).nctioning of its valves
Varices arof the inferior limbs since the more common in the veinse fluid
column above these vesselsThis is the reason why people that is higher.
spend much time standing (e.g.,
surgeons) arvarices. e more susceptible to
In general varicessuperficial veins that appear in the leg are not the apparent
http://www.biology-questions-and-answers.com