62 clinical MCQs in Physiology. Which of the following best describes the slow waves in gastrointestinal smooth muscle? —. Kenya, Africa and global revi...
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Q1. Which of the following best describes the slow waves in gastrointestinal smooth muscle? ---
- They are true action potentials that trigger muscle contraction
- They result from cyclic changes in membrane potential due to sodium ion influx
- They are rhythmic changes in resting membrane potential generated
- They occur independently of any neural or hormonal input
Answer: They are rhythmic changes in resting membrane potential generated
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Q2. Spike potentials in gastrointestinal smooth muscle are mainly triggered by ---
- Sodium ion influx
- Potassium ion efflux
- Chloride ion efflux
- Calcium ion influx
Answer: Calcium ion influx
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Q3. A patient with chronic pancreatitis may experience protein malabsorption primarily due to deficiency of ---
- Pepsin
- Trypsin
- Elastase
- Dipeptidase
- Chronic pancreatitis destroys acinar cells, reducing trypsin output. Pepsin is gastric; dipeptidase is a brush border enzyme — neither…
Answer: Trypsin
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Q4. Which characteristic of bile salts is essential for emulsification of fats? ---
- Nonpolar nature
- Amphipathic structure
- High enzymatic activity
- Ability to hydrolyze lipids
Answer: Amphipathic structure
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Q5. How are triglycerides transported from enterocytes into the lymphatic circulation? ---
- Bound to albumin
- Packaged into chylomicrons
- Transported as free fatty acids
- Covered by bile salts
Answer: Packaged into chylomicrons
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Q6. A patient undergoes surgical resection of the terminal ileum. Which digestive function is most likely impaired? ---
- Protein absorption
- Emulsification of fats
- Recycling of bile salts
- Carbohydrate absorption
Answer: Recycling of bile salts
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Q7. All the following are true regarding the regulation of pancreatic enzyme synthesis EXCEPT ---
- Secretin is released in response to proteins in the duodenum
- Secretin stimulates the production of bicarbonate-rich pancreatic juice
- Cholecystokinin (CCK) is stimulated by the presence of fats in the duodenum
- Cholecystokinin (CCK) triggers the release of digestive enzymes from the pancreas
Answer: Secretin is released in response to proteins in the duodenum
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Q8. All of the following are true about plant fiber in the diet, EXCEPT ---
- Plant fiber retains water in the intestines due to its osmotic effect
- Regulate bowel movements promoting stronger colon contractions
- Can be fermented producing energy from short chain fatty acids
- It enhances nutrient absorption by speeding up digestion
Answer: It enhances nutrient absorption by speeding up digestion
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Q9. GLUT 2 transporters move glucose across cell membranes by ---
- Simple diffusion
- Facilitated diffusion
- Primary active transport
- Secondary active transport
Answer: Facilitated diffusion
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Q10. The cause of slow waves in gastrointestinal smooth muscles is ---
- Na influx only
- Ca influx only
- Na & Ca influx
- Na & Ca efflux
Answer: Na & Ca influx
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Q11. Regarding neural control of the gastrointestinal tract, all are true EXCEPT ---
- Vagus nerve provides more motor than sensory input
- Afferent signals transmitted by sensory nerve fibers initiate GI tract reflexes
- Stimulation of the parasympathetic nerves increases local blood flow
- Stimulation of the sympathetic nerves increase in sphincter contraction
Answer: Vagus nerve provides more motor than sensory input
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Q12. Enterogastrones work in which phase of the gastric secretion process? ---
- Cephalic phase
- Gastric phase
- Early intestinal phase
- Late intestinal phase
Answer: Late intestinal phase
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Q13. The type of salivary secretion from the parotid gland is ---
- Watery, enzyme-rich
- Both serous and mucous
- Thick, viscous, containing mucus
- Mostly mucous
- The submandibular produces mixed; sublingual produces mostly mucous.
Answer: Watery, enzyme-rich
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Q14. Which of the following hormones requires a binding protein for transport in the blood? ---
- Insulin
- Epinephrine
- Cortisol
- Oxytocin
Answer: Cortisol
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Q15. Which of the following statements is true regarding the adrenal glands? ---
- The zona glomerulosa primarily produces glucocorticoids
- 17α-hydroxylase is found in the zona fasciculata
- There is negative feedback from androgens on ACTH
- The zona fasciculata produces active androgens
- Zona glomerulosa makes aldosterone; zona reticularis makes androgens. ACTH feedback is from cortisol, not androgens.
Answer: 17α-hydroxylase is found in the zona fasciculata
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Q16. Which of the following statements regarding the regulation of calcium homeostasis is TRUE? ---
- PTH secretion increases in response to elevated plasma calcium levels
- Calcitonin promotes calcium reabsorption from the kidneys to raise plasma calcium
- Vitamin D enhances intestinal absorption of calcium by increasing expression of calcium-binding proteins
- FGF23 increases plasma calcium by stimulating osteoclast activity
Answer: Vitamin D enhances intestinal absorption of calcium by increasing expression of calcium-binding proteins
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Q17. Which of the following plasma proteins has the highest affinity but lowest capacity for binding thyroxine (T4)? ---
- Transthyretin
- Albumin
- Thyroxine-binding globulin (TBG)
- Thyroxine-binding pre-albumin
Answer: Transthyretin
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Q18. A researcher selectively destroys pancreatic delta cells. Which physiological change is most likely to occur? ---
- Increased glucagon secretion
- Increased somatostatin levels
- Increased blood glucose
- Increased pancreatic polypeptide secretion
Answer: Increased glucagon secretion
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Q19. Both insulin and somatostatin ---
- Are released from extra-pancreatic sites only
- Receptors are linked to G proteins
- Inhibit release of glucagon
- Cause K+ uptake by cells
Answer: Inhibit release of glucagon
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Q20. Secretion of aldosterone would be affected if which layer of the adrenal cortex is damaged? ---
- Zona reticularis
- Zona fasciculata
- Zona glomerulosa
- Zona fasciculata and reticularis
- Fasciculata makes cortisol; reticularis makes sex steroids.
Answer: Zona glomerulosa
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Q21. All of the following bind to intracellular receptors EXCEPT ---
- Cortisol
- Aldosterone
- Thyroxine
- Parathyroid hormone
Answer: Parathyroid hormone
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Q22. Which of the following hormones secreted by the anterior pituitary is not classified as a trophic hormone? ---
Answer: Prolactin
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Q23. Regarding energy stores in the human body, which of the following statements is TRUE? ---
- Fats are more readily available for immediate use than carbohydrates
- Carbohydrates yield more ATP per gram than fats
- Fats provide a much higher total energy reserve than carbohydrates
- Carbohydrates are stored in larger quantities in the body than fats
Answer: Fats provide a much higher total energy reserve than carbohydrates
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Q24. Nutritional essential amino acids include ---
- Glycine
- Serine
- Lysine
- Tyrosine
Answer: Lysine
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Q25. Which of the following lipoproteins is primarily responsible for delivering cholesterol to peripheral tissues? ---
- Chylomicrons
- Very Low-Density Lipoprotein (VLDL)
- Low-Density Lipoprotein (LDL)
- High-Density Lipoprotein (HDL)
Answer: Low-Density Lipoprotein (LDL)
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Q26. Which of the following substances decreases the activity of hormone-sensitive lipase? ---
- Adrenaline
- Thyroxine
- Serotonin
- Prostaglandin E
Answer: Prostaglandin E
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Q27. Kidneys mostly reabsorb sodium by ---
- Simple diffusion
- Secondary active transport
- Primary active transport
- Facilitated diffusion
Answer: Secondary active transport
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Q28. Which part of the Loop of Henle is more permeable to water? ---
- Collecting ducts
- Thin ascending limb
- Thin descending limb
- Distal convoluted tubule
Answer: Thin descending limb
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Q29. Which part of the renal tubule has fewer microvilli and its main function is secretion? ---
- Proximal convoluted tubule
- Loop of Henle
- Distal convoluted tubule
- Collecting duct
Answer: Distal convoluted tubule
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Q30. Which of the following is NOT true about the macula densa? ---
- Release autocrine signals
- Function as chemoreceptors
- Functions as osmoreceptors
- Release paracrine signals
Answer: Release autocrine signals
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Q31. Which cell in the collecting tubule functions in maintaining acid-base balance? ---
- Principal cells
- Intercalated cells
- Tubular cells
- Mesangial cells
- directly regulate acid-base balance by secreting H+ and reabsorbing/secreting HCO3-. Principal cells regulate sodium, water, and…
Answer: Intercalated cells
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Q32. What is the definition of tubular secretion? ---
- The selective transfer of substances from the tubular lumen to the peritubular capillary
- The passive transfer of substances from the glomerulus to the renal tubule
- The selective transfer of substances from the peritubular capillary to the tubular lumen
- The active reabsorption of water from the renal tubule into the bloodstream
Answer: The selective transfer of substances from the peritubular capillary to the tubular lumen
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Q33. Stimulation of the renin-angiotensin-aldosterone system (RAAS) by the kidney primarily occurs in response to ---
- Decreased potassium levels in extracellular fluid
- Decreased atrial natriuretic peptide (ANP) secretion
- Decreased sodium delivery to the distal tubule
- Decreased antidiuretic hormone (ADH) secretion
Answer: Decreased sodium delivery to the distal tubule
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Q34. Which of the following is correct regarding glomerular filtrate? ---
- 99% of glomerular filtration rate excreted
- 1% of glomerular filtration rate reabsorbed
- 50% of glomerular filtration rate reabsorbed
- 1% of glomerular filtration rate excreted
Answer: 1% of glomerular filtration rate excreted
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Q35. Which of the following mechanisms describes the intrinsic ability of blood vessels to constrict in response to an increase in blood pressure? ---
- Hormonal regulation through vasoactive substances
- Sympathetic nervous system control of renal blood flow
- Myogenic response to stretch in vascular smooth muscle
- Tubuloglomerular feedback involving the macula densa cells
- This maintains constant renal blood flow independently of external neural or hormonal input.
Answer: Myogenic response to stretch in vascular smooth muscle
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Q36. During voluntary inhibition of micturition when the bladder is full, which of the following responses occurs? ---
- Inhibit the pelvic nerve
- Inhibit the pudendal nerve
- Inhibit the hypogastric nerve
- Inhibit the parasympathetic system
- to prevent detrusor contraction. The pudendal nerve is kept active to maintain external sphincter contraction.
Answer: Inhibit the pelvic nerve
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Q37. First stimulation in the micturition reflex occurs when the volume of urine in the bladder reaches ---
Answer: 150 ml
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Q38. Which of the following is true about glucose reabsorption from the tubular lumen to the tubular cell in the kidneys? ---
- It is done by carrier-mediated passive transport
- Direction of transport is downhill
- No energy is consumed in the process
- It is done by secondary active transport of sodium
- dragging glucose against its gradient. This is secondary active transport and consumes energy indirectly.
Answer: It is done by secondary active transport of sodium
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Q39. Which of the following is false regarding the reabsorption of bicarbonate ion? ---
- H+ is formed inside the cells then secreted into the tubular fluid
- H+ combines with HCO3- in the tubular fluid forming H2CO3
- CO2 combines with H2O using extracellular carbonic anhydrase
- The renal tubules are poorly permeable to HCO3
Answer: CO2 combines with H2O using extracellular carbonic anhydrase
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Q40. Which of the following hormones is required for absorption of 8–15% of water reabsorbed in the distal convoluted tubule? ---
- Aldosterone
- Antidiuretic hormone (ADH)
- Angiotensin II
- Atrial natriuretic peptide (ANP)
Answer: Antidiuretic hormone (ADH)
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Q41. What is the cause of rapid decrease in pituitary secretion of LH seven days after ovulation? ---
- The anterior pituitary becomes unresponsive to GnRH
- Estrogen from the developing follicles exerts feedback inhibition on the hypothalamus
- The rise in body temperature inhibits hypothalamic release of GnRH
- Corpus luteum secretions suppress hypothalamic secretion of GnRH
Answer: Corpus luteum secretions suppress hypothalamic secretion of GnRH
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Q42. Which of the following could inhibit the initiating of labor? ---
- Administration of an antagonist of the actions of progesterone
- Administration of luteinizing hormone
- Administration of an antagonist of prostaglandin E2 effects
- Administration of oxytocin hormone
- would actually promote labor since progesterone normally suppresses contractions.
Answer: Administration of an antagonist of prostaglandin E2 effects
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Q43. What is the negative feedback signal associated with sperm cell production that inhibits pituitary formation of FSH? ---
- Testosterone
- Inhibin
- Estrogen
- Luteinizing hormone
Answer: Inhibin
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Q44. When do progesterone levels rise to their highest point during the female hormonal cycle? ---
- Between ovulation and the beginning of menstruation
- Immediately before ovulation
- When the blood concentration of LH is at its highest point
- When 12 primary follicles are developing to the antral stage
Answer: Between ovulation and the beginning of menstruation
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Q45. What is the source of the rapid rise of estrogen at the end of menstruation? ---
- Corpus luteum
- Developing follicles
- Endometrium
- Stromal cells of the ovaries
Answer: Developing follicles
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Q46. Which of the following medications can interfere with the emission phase of the male sexual cycle? ---
- Medication that prolongs the duration of action of nitric oxide
- Medication that blocks the smooth muscle receptors for nitric oxide
- Medication that increases the release of nitric oxide
- Medication that inhibits beta-adrenergic receptors
Answer: Medication that inhibits beta-adrenergic receptors
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Q47. A 58-year-old postmenopausal woman has unexpectedly low FSH levels. Which is the most likely explanation? ---
- She has been using hormone replacement therapy containing estrogen
- She has been using calcium and vitamin D supplements since menopause
- Her ovaries have resumed follicular development
- She is experiencing a resurgence of menstrual cycles
Answer: She has been using hormone replacement therapy containing estrogen
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Q48. Why is milk produced only after delivery, not before? ---
- LH and FSH are too low during pregnancy to support milk production
- High levels of progesterone and estrogen during pregnancy suppress milk production
- The alveolar cells of the breast do not reach maturity until after delivery
- High levels of oxytocin are required for milk production and oxytocin is not secreted until the baby stimulates the nipple
Answer: High levels of progesterone and estrogen during pregnancy suppress milk production
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Q49. Men who take large doses of testosterone for long periods are sterile. What is the explanation? ---
- High levels of androgens bind to testosterone receptors in the Sertoli cells
- Overstimulation of sperm cell production results in defective sperm cells
- High levels of androgen compounds inhibit the secretion of gonadotropin-releasing hormone
- High levels of androgen compounds produce hypertrophic dysfunction of the prostate gland
Answer: High levels of androgen compounds inhibit the secretion of gonadotropin-releasing hormone
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Q50. Two days before onset of menstruation, FSH and LH reach their lowest levels. What is the cause? ---
- Anterior pituitary becomes unresponsive to GnRH
- Estrogen from developing follicles exerts feedback inhibition on the hypothalamus
- Rise in body temperature inhibits hypothalamic release of GnRH
- Secretion of estrogen, progesterone, and inhibin by the corpus luteum
Answer: Secretion of estrogen, progesterone, and inhibin by the corpus luteum
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Q51. An XX chromosome baby is born with a penis, scrotum with no testes, no vagina. Which could cause this? ---
- Abnormally high levels of hCG production by trophoblast cells
- Abnormally low rates of estrogen production by the placenta
- Abnormally high levels of LH in the maternal blood
- Abnormally high levels of testosterone in the maternal blood
Answer: Abnormally high levels of testosterone in the maternal blood
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Q52. A man suffers a disease destroying only the motor neurons of the spinal cord below the thoracic region. Which aspect of sexual function would not be possible? ---
- Arousal
- Erection
- Lubrication
- Ejaculation
- Destroying lower motor neurons abolishes this. Psychogenic erection via higher centres could still occur.
Answer: Ejaculation
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Q53. By what mechanism does the combined oral contraceptive prevent pregnancy? ---
- Prevention of the preovulatory surge of luteinizing hormone
- Prevention of development of the ovarian follicles
- Suppressing function of the corpus luteum soon after it forms
- Prevention of normal development of the endometrium
Answer: Prevention of the preovulatory surge of luteinizing hormone
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Q54. An individual suffers a traumatic event and is unable to recall anything from the moment of injury or to retain memories of recent events. This is known as ---
- Dissociative amnesia
- Anterograde amnesia
- Post-traumatic amnesia
- Transient global amnesia
Answer: Anterograde amnesia
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Q55. One of the most widely used tests of executive functioning is the ---
- Manhattan card sorting test
- Quebec number sorting task
- Wisconsin card sorting test
- Minnesota number ordering test
Answer: Wisconsin card sorting test
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Q56. Executive functions are normally associated with which area of the brain? ---
- The parietal cortex
- The temporal cortex
- The prefrontal cortex
- The occipital cortex
Answer: The prefrontal cortex
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Q57. Emotions are ---
- Objective responses to experiences in our environment
- Subjective responses to experiences in our environment
- Physiological changes to experiences in our environment
- Behavioural changes to experiences in our environment
Answer: Subjective responses to experiences in our environment
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Q58. The number of chunks that can be held in short-term memory is typically conceptualised as ---
- 7 plus or minus 2
- 5 plus or minus 2
- 3 plus or minus 2
- 6 plus or minus 3
Answer: 7 plus or minus 2
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Q59. A patient with right-sided removal of the hippocampus would be impaired on which of the following ---
- Short-term verbal memory
- Long-term verbal memory
- Short-term visuo-spatial memory
- Long-term visuo-spatial memory
Answer: Long-term visuo-spatial memory
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Q60. Declarative memory depends on the ; repetition priming depends on the ; procedural memory depends on ---
- Hippocampus; neocortex; basal ganglia
- Hippocampus; basal ganglia; neocortex
- Neocortex; basal ganglia; hippocampus
- Basal ganglia; neocortex; hippocampus
Answer: Hippocampus; neocortex; basal ganglia
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Q61. If you can remember the capital city of Kenya is Nairobi, this is an example of ---
- Episodic memory
- Semantic memory
- Working memory
- Implicit memory
- Procedural memory
Answer: Semantic memory
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Q62. All of the following are true regarding Lower Motor Neurons (LMNs) EXCEPT
- Alpha LMNs synapse with skeletal muscle fibers
- LMN syndrome is characterised by spastic paralysis
- LMN groups are organised topographically in the spinal cord
- LMN lesions may result in fasciculations
Answer: LMN syndrome is characterised by spastic paralysis