dr_kh
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Can someone please explain the changes in systemic venous return and systemic blood pressure with the change in IPP?
AND how does performing valsalva maneuver affect the above listed factors?
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| Alexis
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Before inspiration we have the equilibrium point of the resp syst when IPP is -ve ( -5) and is equal to recoil force and we have the FRC. The alveolar pressure is 0=atmosph pressure.
During inspir the diaphragm contratcs and the IPP becomes more -ve and this makes the lung to expand which leads to a slight decrease in alveolar pressure of gases (they expand to along with the lung). This causes the air to flow into the lungs. And the recoil force increases too ...becasue the IPP becomes more -ve.
End if inspir: when the recoil force = IPP again..we have again equilibrium but at a larger volume of lung. and the TD=500 ml, alveolar pressure is again 0.
Expiration....the diaphragm relaxes and increases IPP which returns to -5 cm...which also makes the recoil force to decrease. This lung deflation makes the alveolar press to become slightly + so the air is flown out of the lungs....which makes the alv press to return to 0...
Hope that helps u.....good luck with the studying....
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| Alexis
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We have a more -ve IPP during inspir so that increases the venous return to the lung ...which increases the preload at the right heart....pulmonary vessels expand and the volume of blood in the pulmonary circuit increases
That makes to decrease the output of the left ventricle which makes a decreased systemic arterial pressure...and an increased heart rate....this is what happens during inspiration.
During expiration...we have an increase of IPP...more +ve and this decreases the syst venous return...the pulmonary vessels are compressed which increases the left ventricle output which increases the syst arterial pressure and by reflex decreases the heart rate.
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| Alexis
Forum Newbie
Topics: 2
Posts: 7
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We have a more -ve IPP during inspir so that increases the venous return to the lung ...which increases the preload at the right heart....pulmonary vessels expand and the volume of blood in the pulmonary circuit increases
That makes to decrease the output of the left ventricle which makes a decreased systemic arterial pressure...and an increased heart rate....this is what happens during inspiration.
During expiration...we have an increase of IPP...more +ve and this decreases the syst venous return...the pulmonary vessels are compressed which increases the left ventricle output which increases the syst arterial pressure and by reflex decreases the heart rate.
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| Alexis
Forum Newbie
Topics: 2
Posts: 7
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IN Valsalva maneuver we have a very positive IPP which makes it similar to the expiration conditions...so u have the answer above...
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