Page 1 of 3: physiology!

sravya · Credits: 28740 My Scrapbook

At the end of isovolumetric contraction the pressure of Lt ventricle is
1:Equal to systolic pressure
2:Diastolic pressure
3:Mean Arterial pressure
4:Pulse pressure

dana · Credits: 3703 My Scrapbook My Reading List 9 Books

Hi Sravya,
gud to have your questions back in this forum.
I think the ans is 2. Diastolic pressure
I am quoting what ganong says about left ventricular pressure in the phase of isovolumetric contraction-

" The period of Isovolumetric contraction lasts for about 0.05sec until the pressures in the left and right ventricles exceed the pressure in the aorta (80 mm Hg and 10.6kPa)and pulmonary artery (10mm Hg) and the aortic & pulmonary valves open."

The left ventricular pressure equals the systolic pressure in the Phase of Ventricular ejection.

dr4jc · Credits: 4396 My Scrapbook

At the end of isovolumetric contraction, the pressure in Lt ventricle should obviously be equal to the systolic pressure in the aorta(120mmHg)...only then blood can move frm ventricle to aorta
(ejection)...so ans is A

dana · Credits: 3703 My Scrapbook My Reading List 9 Books

hi,
the question specifically states teh left ventricular pressure at the end of isovolumetric contraction phase.
The ventricular pressure reaches its peak i.e. systolic pressure during the rapid ejection phase.
Also please note that the pressure in the aorta falls during diastole.It reaches 80 mm Hg during the late diastole of the heart.
That is why when at the end of the isovolumetric phase the ventricular pressure jst exceeds 80mm Hg, it is sufficient to open the aortic valve.
Please refer to the diagram of the ventricular and aortic pressure curves during the cardiac cycle.That should make the ans clear.

bharatvedin · Credits: 4094 My Scrapbook

hi,

i think our DEAR SISTER DANA is right.

i think the pressure shud be equal to diastolic pressure.

THANX!

drche · Credits: 11979 My Scrapbook My Reading List 10 Books

shud be equal to systolic pressure...a

sravya · Credits: 28740 My Scrapbook

hey,

at the end of isovloumetric contraction the pressure is 80mmof hg n in rapid ejection phase the pressure changes to 120 mmof hg! guys! 80 mmof hg means diastolic!

i think i'm not mistaken u go thru the ganong !

byebye!

dr4jc · Credits: 4396 My Scrapbook

from the graph what I percieve is that the pressure should be more than 80mmHg if ejection has to occur...after ejection finishes the pressure drops to 80mmHg...so ans would still be A

dr4jc · Credits: 4396 My Scrapbook

The ejection phase is followed by the diastolic phase where the pressure drops still lower to nearly 0 for blood to fill the ventricles

sneha_usmle · Credits: 1527 My Scrapbook

though the diastolic pressure drops to ''0''at the end wat we willtake in usual for diastloic blood pressre is 80 mmof hg!n systloic 120 mm of hg!

the steps r like this!

in isovolumetric contraction blood pressure steeply rises to 80 mm of hg n
semi lunar valves will open!here ends isvc!

2. now rapid ejection phase lt ventricle sstarts contracting so though the bllood pressure doesnot raise much but still ventrile is contracting so rises to 120 mm of hgslowly! now here it reaches 120 mm of hg!

let me quote u sthg from nalpak !in heart mechanics it is clearly given that--- closure of the aortic valve termintaes isvc and begins ejection phase! see the graf! u will get an idea!
i guess sravya's answer is justified!i also think the same!
welcome for any differences!

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