What occurs in the afferent and efferent arterioles due to Angiotensin II activity?

Angiotensin II plays a crucial role in the regulation of blood pressure and fluid balance in the body. Its primary effect is to cause vasoconstriction, particularly in the efferent arterioles of the nephron. This constriction increases the glomerular hydrostatic pressure, leading to enhanced glomerular filtration.

In contrast, Angiotensin II induces dilation of the afferent arterioles. This dilation allows for increased blood flow into the glomeruli, which helps to maintain or increase glomerular filtration rate, particularly in states of low blood volume or low blood pressure.

The combination of these two effects—dilation of the afferent arterioles alongside constriction of the efferent arterioles—enhances glomerular filtration pressure and allows the kidney to maintain its functional output despite fluctuating systemic pressures. This is essential for maintaining homeostasis and ensuring adequate filtration of blood through the kidneys.

This physiological response is particularly important in situations such as dehydration or blood loss, where the body's overall blood volume may be compromised. The action of Angiotensin II ensures that the kidneys continue to filter blood efficiently despite these challenges. Therefore, the correct answer highlights this specific action of Angiotensin II on both