Final answer:
ANP increases the surface area for filtration by dilating afferent arterioles and constricting efferent arterioles, increasing the GFR. It also inhibits the reabsorption of sodium and water, thus reducing blood volume and pressure.
Step-by-step explanation:
The heart's atrial cells secrete the hormone atrial natriuretic peptide (ANP) in response to increased blood volume, causing dilation of the afferent arterioles and constriction of the efferent arterioles in the kidneys. This action increases the surface area available for filtration, leading to increased glomerular filtration rate (GFR). ANP also inhibits the reabsorption of sodium and water by the renal tubules, and suppresses the release of renin and aldosterone, reducing blood volume and pressure and promoting diuresis.
Atrial Natriuretic Peptide (ANP) increases the surface area for filtration by causing vasodilation of the afferent arteriole and vasoconstriction of the efferent arteriole. This leads to an increased glomerular filtration rate (GFR) because it allows more blood to enter the glomerulus while slowing down the blood flow leaving the glomerulus. ANP also decreases sodium reabsorption in the distal convoluted tubule, which promotes water loss and further increases GFR.