MDS PREP
What is the primary neurotransmitter released by the parasympathetic nervous system?
1) Norepinephrine
2) Acetylcholine
3) Serotonin
4) Dopamine
The parasympathetic nervous system primarily uses acetylcholine as its neurotransmitter, which acts on muscarinic receptors to produce its characteristic effects on various organs.
Which type of receptors are involved in the contraction of the detrusor muscle during micturition?
1) Muscarinic receptors
2) Adrenergic receptors
3) Dopaminergic receptors
4) Serotonergic receptors
The contraction of the detrusor muscle during micturition is mediated by the activation of muscarinic receptors (specifically M3 receptors) on the smooth muscle cells of the detrusor. This leads to increased muscle tone and the expulsion of urine from the bladder.
What is the primary stimulus for the secretion of Secretin?
1) High blood glucose levels
2) Low pH in the duodenal lumen
3) The presence of fatty acids and amino acids in the duodenal lumen
4) Stretching of the duodenal wall
The primary stimulus for the secretion of Secretin is low pH in the duodenal lumen, which indicates the presence of acidic chyme.
What is the primary function of the pharyngeal stage of deglutition?
1) Voluntary contraction of the pharyngeal muscles to move food into the esophagus
2) Relaxation of the upper esophageal sphincter
3) Closure of the epiglottis to prevent aspiration of food into the trachea
4) Involuntary contraction of the pharyngeal muscles to propel the food bolus into the esophagus
E) Stimulation of salivary glands to secrete saliva
The pharyngeal stage of deglutition involves involuntary contraction of the pharyngeal muscles and is responsible for the rapid passage of the food bolus from the oral cavity to the upper esophagus. It is primarily a reflex act triggered by the voluntary movement of food into the back of the mouth.
In which sleep stage are delta waves most prominent?
1) Stage 1 NREM
2) Stage 2 NREM
3) Stage 3 NREM
4) REM sleep
Delta waves are high-amplitude, low-frequency brain waves that are most prominent during the deepest stage of NREM sleep, which is Stage 3 NREM, indicating deep sleep.
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 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.
What is the primary site of vitamin B12 absorption in the intestine?
1) Stomach
2) Duodenum
3) Jejunum
4) Ileum
Physiology
Answer: 4
The ileum is the primary site of vitamin B12 absorption, facilitated by intrinsic factor binding to specific receptors.