MDS PREP
MCQ: 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
Luteinizing hormone (LH) stimulates the development of the corpus luteum and the secretion of progesterone, which is crucial for maintaining the uterine lining.
What is the primary mechanism of the inhibitory postsynaptic potential (IPSP) in the nervous system?
1) Activation of sodium channels causing depolarization
2) Activation of potassium channels causing hyperpolarization
3) Activation of chloride channels causing depolarization
4) Activation of calcium channels causing hyperpolarization
Answer: 2) Activation of potassium channels causing hyperpolarizationExplanation: IPSPs are typically generated when a neurotransmitter binds to GABA receptors on the postsynaptic membrane of a neuron, causing potassium channels to open and leading to efflux of K+ ions. This hyperpolarizes the neuron, reducing the likelihood of an action potential.
What is the role of the corpus luteum in the second half of the menstrual cycle?
1) It secrets FSH
2) It secrets LH
3) It secrets estrogen and progesterone
4) It secrets inhibin
The corpus luteum secretes estrogen and progesterone during the second half of the menstrual cycle, which are essential for maintaining the uterine lining.
What is the primary role of the cephalic phase of gastric acid secretion?
1) Stimulation of gastrin release in the stomach
2) Secretion of gastric juices in response to the thought or smell of food
3) Increase in gastric motility
4) Secretion of gastric juices in response to food entering the duodenum
Physiology
Answer: 2
The cephalic phase of gastric acid secretion is initiated by the parasympathetic system and is triggered by the sight, smell, or thought of food. It accounts for approximately 20% of total acid secretion and prepares the stomach for digestion even before food arrives.