NEET MDS Shorts
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PhysiologyGastric emptying is regulated by a combination of vagal reflexes, intestinal hormones such as secretin and cholecystokinin, and local neural reflexes known as the enterogastric reflex. These mechanisms work in concert to modulate the rate of emptying based on the needs of the body.
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PhysiologyAround day 11 of the menstrual cycle, the rising estrogen level reaches a threshold that has a positive feedback effect on LH secretion, leading to the LH surge. This LH surge is essential for ovulation to occur.
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PhysiologyAnswer: 1) Dilatation (mydriasis)Explanation: Norepinephrine acts on alpha-adrenergic receptors in the pupillary dilator muscles, leading to pupil dilation. This is a component of the sympathetic nervous system's response to stress, which also includes pupil dilatation mediated by epinephrine.
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PhysiologyAnswer: 1) ContractionExplanation: Norepinephrine acts on alpha-adrenergic receptors on the pupillary dilator muscle, causing its contraction and pupil dilatation (mydriasis). This is part of the sympathetic nervous system's response to stress and increased alertness during the fight-or-flight response.
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PhysiologyAnswer: 1) DepolarizationExplanation: EPSPs occur when the neurotransmitter binds to postsynaptic receptors that open sodium channels, allowing sodium ions to flow into the neuron and causing the membrane to depolarize. This increases the excitability of the neuron, bringing the membrane potential closer to the threshold for action potential firing.
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PhysiologyAnswer: 1) Thyroxine binding globulin (TBG) is increased during pregnancy, which is a major thyroid hormone binding protein in the plasma.
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PhysiologyThe primary stimulus for the secretion of Secretin is low pH in the duodenal lumen, which indicates the presence of acidic chyme.
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PhysiologySpermatogenesis, the process of producing mature sperm cells from spermatogonia, takes approximately 74 days in humans. This includes the development of spermatids and their subsequent transformation into spermatozoa.