Compare and contrast the hemodynamic responses when a person moves from the upright to the upside-down position on Earth and in a microgravity environment.

 

Answer:

The hemodynamic responses when a person moves from upright to the upside down position in Earth simulates the hemodynamic responses in a microgravity environment. However, adaptive changes happen during upside position in a microgravity environment.

Step-by-step explanation

When a person moves from upright to upside down position in Earth, there will be a fluid shift that increases the venous return to the heart. This leads to an increase in the stroke volume and cardiac output. There will be a transient increase in the blood pressure.

In a microgravity environment, there is a fluid shift that increases venous return to the heart that also leads to the increase in the stroke volume of the heart. However, adaptive changes in a microgravity environment happen. Despite the increase in cardiac output, the blood pressure remains the same or slightly decreases. The mean arterial pressure remains unchanged as well because of the dilation of the arterial resistance vessels. This induces a decrease in systemic vascular resistance.