MDS PREP
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.
Which of the following is NOT a secondary bile acid?
1) Cholic acid
2) Deoxycholic acid
3) Lithocholic acid
4) Chenodeoxycholic acid
Cholic acid is NOT a secondary bile acid; it is a primary bile acid synthesized in the liver from cholesterol.
What happens when the transport maximum for glucose is exceeded?
1) All excess glucose is reabsorbed
2) Some glucose is reabsorbed and some is excreted
3) All excess glucose is excreted in the urine
4) No glucose is excreted regardless of the amount
When the transport maximum for glucose is exceeded, some glucose is reabsorbed and some is excreted in the urine, leading to glucosuria.
What is the primary effect of norepinephrine on blood vessels during the fight-or-flight response?
1) Vasodilatation in most vessels
2) Vasoconstriction in most vessels
3) Vasodilatation in arterioles of skeletal muscles and the heart
4) Vasoconstriction in arterioles of skeletal muscles and the heart
Answer: 2) Vasoconstriction in most vesselsExplanation: Norepinephrine acts on alpha-adrenergic receptors in the vascular smooth muscles, causing vasoconstriction in most blood vessels. This diverts blood flow to critical organs like the brain and muscles, preparing the body for physical exertion.
What is the primary function of the Adrenal Medulla in the fight-or-flight response?
1) Secretion of cortisol
2) Secretion of epinephrine and norepinephrine
3) Secretion of aldosterone
4) Secretion of thyroxine
Answer: 2) Secretion of epinephrine and norepinephrineExplanation: The Adrenal Medulla is part of the sympathetic nervous system and produces the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline) in response to stress or danger. These hormones are crucial for the fight-or-flight response, which prepares the body for immediate action by increasing heart rate, blood pressure, and diverting blood flow to the muscles and brain.
What is the primary mechanism by which acid secretion is regulated in the stomach?
1) By the pH of the stomach content
2) By the amount of food present
3) By the time of day
4) By the type of food consumed
Physiology
Answer: 1
The primary mechanism by which gastric acid secretion is regulated is through the feedback loop involving the pH of the stomach content. Low pH inhibits further acid secretion by decreasing the release of gastrin and the responsiveness of parietal cells to gastrin.
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.
In the presence of which substance does vitamin B12 combine in the stomach to prevent its degradation by gastric acid?
1) Intrinsic factor
2) Pepsin
3) Gastric acid
4) Pancreatic amylase
Physiology
Answer: 1
Vitamin B12 combines with intrinsic factor to form a complex that is protected from degradation by gastric acid.