MDS PREP
What are the two major functions of GH?
1) Stimulation of growth hormone-dependent lipolysis and glycogenolysis
2) Stimulation of gluconeogenesis and growth of the skeletal system
3) Stimulation of cortisol synthesis and thyroid hormone release
4) Regulation of insulin secretion and cardiovascular function
Answer: 2) The two major functions of GH are the growth of the skeletal system and metabolic effects, including gluconeogenesis.
What is the primary mechanism by which the pancreas regulates the activity of its own enzymes in the small intestine?
1) By secreting specific enzyme inhibitors
2) By controlling the pH of pancreatic juice
3) By altering the concentration of bile salts
4) Through the action of the sphincter of Oddi
E) By regulating the flow of pancreatic juice into the intestine
The pancreas secretes specific enzyme inhibitors, such as trypsin inhibitor, to prevent the premature activation of pancreatic enzymes in the pancreas itself. These inhibitors are degraded in the duodenum when the enzymes encounter the higher pH, allowing the enzymes to become active and participate in the digestion of food. Additionally, the presence of food in the intestine triggers the release of secretin, which stimulates the pancreas to secrete bicarbonate to neutralize acidic chyme and create an optimal environment for enzyme activity.
The macula densa is found in:
1) The proximal convoluted tubule
2) The loop of Henle
3) The distal convoluted tubule
4) The collecting duct
The macula densa is a specialized group of epithelial cells located in the distal convoluted tubule at the junction with the afferent and efferent arterioles. It plays a role in the tubulo-glomerular feedback mechanism to regulate renal blood flow and glomerular filtration rate.
What is the primary difference between type IIA and type IIB muscle fibers?
1) Presence of myoglobin in type IIA fibers
2) Metabolic profile (oxidative vs glycolytic)
3) Location in the muscle
4) Size of the fibers
Type IIA fibers are oxidative-glycolytic, meaning they have a mix of oxidative and glycolytic metabolism, while type IIB fibers are purely glycolytic, relying on anaerobic metabolism for energy production during high-intensity, short-duration contractions.
What is the primary neurotransmitter involved in the sympathetic nervous system's response at the neuromuscular junction?
1) Acetylcholine
2) Norepinephrine
3) Epinephrine
4) Dopamine
Answer: 2) The primary neurotransmitter involved in the sympathetic nervous system's response at the neuromuscular junction is norepinephrine, which acts on alpha and beta-adrenergic receptors.
Norepinephrine is stored at the
1. Preganglionic parasympathetic nerve endings
2. Postganglionic parasympathetic nerve endings
3. Preganglionic sympathetic nerve endings
4. Postganglionic sympathetic nerve endings
Physiology
Answer: 2
Norepinephrine is stored at the Postganglionic parasympathetic nerve endings
What is the significance of the increased pulse rate and blood pressure during REM sleep?
1) It indicates the body is preparing for wakefulness
2) It is a byproduct of increased brain activity during dreaming
3) It is not significant and does not reflect any physiological changes
4) It indicates a pathological condition
The increased pulse rate and blood pressure during REM sleep are associated with the heightened brain activity and autonomic system arousal that occurs during this phase of sleep, despite the presence of muscular atonia.
In which brain regions are Broca's and Wernicke's areas located?
1) Inferior temporal gyrus and superior parietal gyrus
2) Inferior frontal gyrus and superior temporal gyrus
3) Superior frontal gyrus and middle temporal gyrus
4) Inferior parietal lobule and superior occipital gyrus
Answer: 2) Broca's area is located in the inferior frontal gyrus and is involved in motor speech, while Wernicke's area is located in the superior temporal gyrus and is associated with language comprehension.