Take the 2-minute tour ×
Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. It's 100% free, no registration required.

For further investigation into the progress of the blood pressure, we will measure a patient's blood pressure in the superior vena cava measured during inhalation and during an exhalation. His heart function remains the same during the measurements

Why is this subject's blood pressure in the superior vena cava during inhalation less than during the exhalation?

share|improve this question
add comment

1 Answer 1

The diaphragm moves down during inspiration. This leads to air being sucked in, due to the pressure difference created. The converse is true during expiration. As the thoracic space is where the SVC sits, it's pressure decreases during inspiration as it is subjected to the surrounding decrease in pressure.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.