The hormone secretin, released by the duodenal mucosa, primarily stimulates the pancreas to secrete:
A. Insulin
B. Water and bicarbonate ions
C. Glucagon
D. Digestive enzymes
Answer: Option B
Solution (By JKSSB Mock Tests)
Secretin is a peptide hormone released by the S cells of the duodenal mucosa in response to acidic chyme entering from the stomach. Its primary action is to stimulate the pancreatic ductal cells to secrete a large volume of water and bicarbonate ions. This alkaline juice neutralizes the acidic chyme, providing the optimal pH for pancreatic digestive enzymes to function. Cholecystokinin (CCK) stimulates enzyme secretion.
Explanation:
The pleura consists of visceral pleura (adhering to lungs) and parietal pleura (lining chest wall), with pleural fluid between them reducing friction during breathing. Pericardium surrounds the heart, peritoneum lines the abdominal cavity, meninges cover the brain and spinal cord.
Explanation:
Prokaryotic cells contain 70S ribosomes, which are composed of a 50S large subunit and a 30S small subunit. The 'S' stands for Svedberg units, a measure of sedimentation rate. Eukaryotic cytoplasm contains 80S ribosomes, though their mitochondria and chloroplasts contain 70S ribosomes.
Explanation:
Guttation occurs when root pressure forces water out through special pores (hydathodes) at leaf tips/margins, forming droplets, usually at night or early morning. Transpiration is vapor loss, evaporation from wet surfaces, precipitation is rain.
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