Ohio Assessment for Educators (OAE) Integrated Science (024) Practice Exam

What is hydrostatic pressure in the context of the circulatory system?

1. The pressure that draws fluid back into the blood vessel

2. The pressure exerted by the heart's contractions

3. The pressure within a blood vessel tending to push water out

4. The pressure influencing osmotic balance

The correct answer is: The pressure within a blood vessel tending to push water out

Hydrostatic pressure in the context of the circulatory system refers to the pressure exerted by the fluid (in this case, blood) within the blood vessels that tends to push water and solutes out of the vascular space into the surrounding tissues. This pressure is critical for the process of capillary exchange, where nutrients and oxygen are delivered to tissues while waste products are removed. The hydrostatic pressure is primarily generated by the force of the heart's contractions propelling the blood through these vessels, creating a gradient that facilitates this movement. Under normal physiological conditions, hydrostatic pressure is balanced by osmotic pressure, which pulls fluid back into the blood vessels. This dynamic is essential for maintaining fluid balance within the tissues and ensuring proper nutrient delivery and waste removal. Understanding hydrostatic pressure is crucial for comprehending how the circulatory system functions in maintaining homeostasis in the body.