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In the presence of antidiuretic hormone (ADH), which part of the nephron becomes highly permeable to water?
1) Proximal Convoluted Tubule (PCT)
2) Loop of Henle
3) Collecting Duct
4) Afferent Arteriole
The post-prandial alkaline tide refers to the increase in blood bicarbonate levels that occurs after a meal due to the secretion of bicarbonate by the pancreas and duodenal mucosa to neutralize the acidic chyme entering the small intestine. This temporary rise in blood pH reduces the secretion of gastrin and therefore decreases gastric acidity.
What is the role of the post-prandial alkaline tide in the regulation of gastric pH?
1) It increases gastric acidity
2) It decreases gastric acidity
3) It has no effect on gastric acidity
4) It neutralizes gastric acid
E) It promotes the secretion of bicarbonate into the gastric lumen
LH is responsible for the transformation of the follicle into the corpus luteum and the initiation of progesterone production during the luteal phase of the menstrual cycle.
Which of the following hormones stimulates the development of the corpus luteum and the secretion of progesterone?
1) Follicle-stimulating hormone (FSH)
2) Luteinizing hormone (LH)
3) Estrogen
4) Progesterone
Which of the following statements about Secretin is true?
1) It is structurally similar to insulin.
2) It is structurally similar to glucagon.
3) It stimulates the release of hydrochloric acid by the stomach.
4) It is secreted in response to high blood glucose levels.
Answer: 1) Activation of glycogen phosphorylase by epinephrine
Explanation: Epinephrine acts on the beta-adrenergic receptors of liver and muscle cells, which activate protein kinase. This kinase then phosphorylates and activates glycogen phosphorylase, an enzyme that breaks down glycogen into glucose-1-phosphate, which is rapidly converted to glucose-6-phosphate for use in glycolysis or for release into the bloodstream to maintain glucose levels during stress.
What is the primary mechanism of the fight-or-flight response in the regulation of glycogenolysis?
1) Activation of glycogen phosphorylase by epinephrine
2) Inhibition of glycogen synthase by cortisol
3) Stimulation of glucose-6-phosphatase by thyroid hormones
4) Activation of hexokinase by norepinephrine
In which part of the nephron is bicarbonate primarily reabsorbed?
1) Loop of Henle
2) Distal convoluted tubule
3) Proximal convoluted tubule
4) Collecting duct
Answer: 4) Increased parathyroid hormone during pregnancy stimulates liberation of calcium ions from maternal bones for the fetus's calcium needs.
What is the effect of increased parathyroid hormone during pregnancy?
1) Decreased calcium ion liberation from maternal bones
2) Increased calcium ion absorption in the gut
3) Increased calcium ion excretion in the urine
4) Increased calcium ion mobilization from maternal bones for fetal use
Ponto-genital occipital spikes, or PGO waves, are characteristic of REM sleep and are thought to be associated with the onset of dreaming, as they often coincide with rapid eye movement and increased brain activity during this phase.
What is the significance of the ponto-genital occipital spikes seen in REM sleep?
1) They indicate deep sleep
2) They indicate the onset of dreaming
3) They are associated with eye movement
4) They are markers of REM sleep
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