Mean systemic filling pressure (Psf) and gravity

[Dr.Bajaber]

I was reading about the effect of gravity on the heart from . When a person goes from supine to an upright posture, pressure in the dependent veins increases,blood volume in the dependent veins increases,VR decreases"
If venus pressure increases in the veins this means the mean systemic filling pressure (Psf) should increase and according to what we know Psf is the pressure head, and since gravity causes less pressure in the right atrium, this mean we have more pressure gradient Venus return=Psf-Right atrial pressure over compliance. Why do we have increased venus return? I am confused. Can anyone explain?

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[Dr.Bajaber]

I kinda feel I got it
Wiki "The reason for this is when a person initially stands, cardiac output and arterial pressure decrease (because right atrial pressure falls). The flow through the entire systemic circulation falls because arterial pressure falls more than right atrial pressure; therefore the pressure gradient driving flow throughout the entire circulatory system is decreased"
Thanks anyways .How can I delete the post ?

 

[Phloston]

I kinda feel I got it
Wiki "The reason for this is when a person initially stands, cardiac output and arterial pressure decrease (because right atrial pressure falls). The flow through the entire systemic circulation falls because arterial pressure falls more than right atrial pressure; therefore the pressure gradient driving flow throughout the entire circulatory system is decreased"
Thanks anyways .How can I delete the post ?

These types of posts generally aren't deleted because people checking the thread will probably benefit from at least transiently contemplating the topic.

I'm not entirely sure what your question is, as it sounds more just you thinking aloud / through writing. But yes, supine --> standing causes decreased VR and reduced RA preload. Vascular tonal and cardiac chrono-/inotropic changes follow to boost the RA / maintain CO.