starbrite520
Forum Guru
Topics: 130
Posts: 428
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HELP
okay very embaressing but.. i am so confused , utterly confused
what constricts what dilates? when wh y?
what is it when its veno constriction, rather then vasoconstrictin. why does it happen, to what responses? stimulations?
same with veno/vaso dilations, and artery dilations and constrictions
im so confused
i know that if arterial pressure would decrease, then there is vaso constriction to conserve the pressure.
but then at the same time there is vasoconstrictin if there is increased perfusion pressure
im sorry, my mind is running a blank, and im mixing it up
can someone give me a sort of high yield way to kno when its dilate n when its constrict nw hy, in the body,s diff systems
im drawing a blank while studying at the library
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| drhouse
Forum Senior
Topics: 21
Posts: 192
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hey starbrite520,
pl b clear wot do u want to know..
u r making confusion worse by yr question
___________________
everybody can do it.... its just matter of time
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| tompat
Forum Elite
Topics: 36
Posts: 319
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well this what my impression is.
veno constriction is constriction of VEINS
vasoconstriction is constriction of VESSELS that cud be artery or vein or both, generally meant both.
venoconstriction--
this happens when there is less blood in the circulation as u must be knowing veins are primary reservoirs of extra blood in circulatory tree.
drugs containing nitrites dilate veins and decrease blood pressure.
vasoconstriction--
this also happens when there is less of blood in system to normalise the blood pressure.
when arteriols dilate the blood pressure decreases, mainly diastolic.
drugs such as hydralazine n diazoxide and minoxidil cause arteriolar dilation.
remember arteries are RESISTANCE vessels while VEINS are CAPACITANCE VESSELS.
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body has intrensic n natural tendency to prevent any harm that is being incured on it thru altered physiology.
consider low blood pressure, here veins will store less blood and arteries will also have lessened their capacity so that less blood remains at a normal pressure and any ischemic injury is avoided.
now if we have incresed perfusion pressure to the extent that the pressure itself is damaging the end organ then there wud be such resposes so as to decrease the effect of pressure. hence in this case arterioles or vessels supplying that portion will constrict and blood flow is decreased.
this is what i think.
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