MDS PREP
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
The primary role of the cephalic phase of gastric acid secretion is the secretion of gastric juices in response to the thought or smell of food, preparing the digestive system for incoming food.
What is the primary function of chymotrypsin in the digestive process?
1) Converting chymotrypsinogen into chymotrypsin
2) Breaking down proteins into peptides
3) Catalyzing the hydrolysis of disulfide bonds in proteins
4) Activating pepsinogen into pepsin
E) Releasing gastrin from gastric mucosa
Chymotrypsin is an endopeptidase enzyme that plays a crucial role in the digestive system by breaking down proteins into smaller peptides. It is activated from its precursor chymotrypsinogen by the enzyme trypsin. Once active, chymotrypsin hydrolyzes the peptide bonds at the carboxyl side of aromatic and bulky amino acids, such as phenylalanine, tryptophan, and tyrosine. This process is essential for the further digestion and absorption of dietary proteins.
Which of the following statements about glomerular filtrate is true?
1) It contains high levels of proteins.
2) It is isotonic to plasma.
3) It is essentially protein-free.
4) It has a higher concentration of glucose than plasma.
Glomerular filtrate is essentially protein-free, allowing for the passage of water, electrolytes, and small molecules while retaining larger proteins in the bloodstream.
What is the equilibrium potential for sodium (Na+) ions in a typical neuron?
1) -60 mV
2) -90 mV
3) +60 mV
4) +90 mV
Answer: 3) The equilibrium potential for sodium (Na+) ions in a typical neuron is +60 mV.
Which of the following is NOT an action of bile salts?
1) Emulsification of fat
2) Facilitation of fat absorption
3) Neutralization of stomach acid
4) Conjugation of bile acids
Physiology
Answer: 3
Bile salts are involved in the emulsification and absorption of fat, not in neutralizing stomach acid.
What type of aphasia is associated with lesions in the temporal lobe's auditory association area?
1) Broca's aphasia
2) Wernicke's aphasia
3) Global aphasia
4) Sensory aphasia
Wernicke's aphasia is associated with lesions in the temporal lobe's auditory association area, particularly Brodmann's area 22. It is characterized by fluent speech with impaired comprehension and repetition.
What is the most common cause of vitamin D deficiency?
1) Inadequate sunlight exposure
2) Poor dietary intake of vitamin D
3) Impaired liver function
4) Impaired kidney function
Physiology
Answer: 1
Vitamin D deficiency is most commonly due to insufficient exposure to sunlight, as the skin synthesizes vitamin D when exposed to UVB radiation. Other factors include poor dietary intake and impaired conversion or absorption in the liver and kidneys.
What is the normal plasma concentration of glucose that does not lead to its excretion in the urine?
1) 100 mg/100 ml
2) 180 mg/100 ml
3) 200 mg/100 ml
4) 250 mg/100 ml
Physiology
Answer: 1
In a healthy individual, glucose is completely reabsorbed when the plasma concentration is 100 mg/100 ml or less.