MDS PREP
What is the effect of Secretin on the contraction of the pyloric sphincter?
1) It relaxes the pyloric sphincter.
2) It contracts the pyloric sphincter.
3) It has no effect on the pyloric sphincter.
4) It depends on the presence of gastrin.
Secretin has no effect on the contraction of the pyloric sphincter, which is primarily regulated by other hormones.
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.
The primary site of absorption for:
1) Calcium - Jejunum
2) Iron - Jejunum
3) Vitamin B12 - Duodenum
4) All of the above
The small intestine, particularly the duodenum and jejunum, are responsible for the absorption of various nutrients. Calcium and iron are mainly absorbed in the duodenum, while vitamin B12 absorption primarily occurs in the ileum with the help of intrinsic factor.
What are the main stimuli that increase the secretion of growth hormone (GH)?
1) High blood glucose levels and physical inactivity
2) Hypoglycemia, exercise, protein meals, and stress
3) REM sleep and increased IGF-1 levels
4) High cortisol and fatty acid levels
Answer: 2) Main stimuli that increase GH secretion include hypoglycemia, exercise, protein meals, and stress.
What is the role of gastrin in the gastric phase of acid secretion?
1) It is released by the pancreas and stimulates acid secretion in the stomach
2) It is released by the duodenum and inhibits acid secretion
3) It is released by the stomach and stimulates acid secretion in response to food
4) It has no role in gastric acid secretion
Gastrin is released by the stomach and stimulates acid secretion in response to food, playing a key role in the gastric phase of digestion.
What is the primary neurotransmitter involved in the sympathetic nervous system's response at the neuromuscular junction?
1) Acetylcholine
2) Norepinephrine
3) Epinephrine
4) Dopamine
Answer: 2) The primary neurotransmitter involved in the sympathetic nervous system's response at the neuromuscular junction is norepinephrine, which acts on alpha and beta-adrenergic receptors.
What is the effect of stimulating the cholinergic system in the male reproductive system?
1) Decreased testosterone secretion
2) Decreased penile erection
3) Increased testosterone secretion
4) Increased penile erection
Stimulation of the cholinergic system can lead to increased penile erection due to the vasodilation of blood vessels in the penis, allowing for greater blood flow and engorgement of the corpora cavernosa.
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.