The hormone that stimulates the kidney to reabsorb sodium and water, increasing blood pressure, is:
A. Renin
B. Aldosterone
C. ADH
D. ANP
Answer: Option B
Solution (By JKSSB Mock Tests)
Aldosterone, from the adrenal cortex, acts on the distal tubule and collecting duct to increase sodium reabsorption (and water follows) and potassium secretion, raising blood volume and pressure. ADH increases water reabsorption, ANP reduces sodium reabsorption, renin is an enzyme initiating the RAAS.
Explanation:
Myelin, a lipid-rich sheath formed by Schwann cells (PNS) or oligodendrocytes (CNS), insulates axons, allowing saltatory conduction—impulses jump from one node of Ranvier to the next, greatly speeding up transmission. It also conserves energy. Demyelinating diseases like multiple sclerosis slow conduction.
Explanation:
The beta cells of the pancreatic islets of Langerhans produce insulin, which lowers blood glucose by promoting cellular uptake and glycogen synthesis. The liver stores glucose, the spleen filters blood, the thyroid regulates metabolism.
Explanation:
The liver is the primary site of glycogen storage and releases glucose into the blood between meals (glycogenolysis) to maintain blood sugar. Muscles also store glycogen but for local use. The pancreas regulates blood sugar via insulin/glucagon, spleen stores blood and recycles iron, kidneys excrete waste.
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