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Multiple Choice
What is the most direct function of the juxtaglomerular apparatus in the kidney?
A
Reabsorption of glucose from the filtrate
B
Secretion of antidiuretic hormone (ADH)
C
Regulation of blood pressure by releasing renin
D
Filtration of blood to form urine
Verified step by step guidance
1
Understand the role of the juxtaglomerular apparatus (JGA): The JGA is a specialized structure in the kidney located near the glomerulus. Its primary function is to regulate blood pressure and the filtration rate of the glomerulus.
Learn about renin release: The JGA contains juxtaglomerular cells that release renin, an enzyme that plays a key role in the renin-angiotensin-aldosterone system (RAAS). This system helps regulate blood pressure and fluid balance.
Clarify the mechanism of renin: Renin converts angiotensinogen (produced by the liver) into angiotensin I. Angiotensin I is then converted into angiotensin II by the enzyme angiotensin-converting enzyme (ACE), primarily in the lungs. Angiotensin II causes vasoconstriction and stimulates the release of aldosterone, which increases sodium and water reabsorption, raising blood pressure.
Differentiate the JGA's function from other kidney processes: The JGA does not directly reabsorb glucose, secrete antidiuretic hormone (ADH), or filter blood to form urine. These functions are performed by other parts of the kidney, such as the proximal tubule, posterior pituitary gland, and glomerulus, respectively.
Conclude the direct function: The most direct function of the juxtaglomerular apparatus is the regulation of blood pressure by releasing renin, which initiates the RAAS pathway.