MDS PREP
What is the primary function of vitamin D in the body?
1) Blood clotting
2) Bone formation and maintenance
3) Vision
4) Immune system function
Physiology
Answer: 2
Vitamin D is essential for the absorption of calcium and phosphorus from the diet, which are critical for bone formation and maintenance. It also plays roles in muscle function and immune system regulation, but its primary function is in the skeletal system.
MCQ: The gastrocolic reflex is:
1) The contraction of the stomach triggered by the presence of food in the duodenum
2) The contraction of the small intestine triggered by the presence of food in the stomach
3) The contraction of the rectum triggered by the presence of food in the stomach
4) The contraction of the gallbladder triggered by the presence of food in the small intestine
The gastrocolic reflex is the contraction of the colon triggered by the presence of food in the stomach, facilitating bowel movements.
What is the normal ratio of glycine to taurine conjugates of bile acids in the bile?
1) 1:1
2) 2:1
3) 3:1
4) 4:1
The normal ratio of glycine to taurine conjugates of bile acids in the bile is approximately 3:1, reflecting the different conjugation patterns of bile acids.
What are the primary metabolic effects of GH?
1) Lipolysis and protein anabolism
2) Lipolysis and gluconeogenesis
3) Lipolysis and increased peripheral utilization of glucose
4) Lipolysis and increased uptake of glucose by muscles
Answer: 2) The primary metabolic effects of GH are lipolysis and gluconeogenesis, which result in increased plasma fatty acids and glucose levels.
What is the primary role of estrogen during the follicular phase of the menstrual cycle?
1) Suppression of FSH secretion
2) Stimulation of follicular development
3) Preparation of the endometrium for implantation
4) Induction of the LH surge
During the follicular phase of the menstrual cycle, estrogen stimulates follicular development, promoting the maturation of ovarian follicles.
Angiotensin I is formed by the action of which enzyme on Angiotensinogen?
1) Renin
2) ACE
3) Aldosterone
4) Erythropoietin
Angiotensin I is formed by the action of renin on Angiotensinogen, which is produced by the liver and released into the bloodstream.
What is the primary mechanism by which insulin stimulates glucose uptake in the liver?
1) Induction of glucokinase
2) Increase in glycolysis rate
3) Inhibition of gluconeogenesis
4) Stimulation of glycogenolysis
Answer: 1) Induction of glucokinaseExplanation: Insulin enhances glucose uptake in the liver by inducing the synthesis of glucokinase, an enzyme that converts glucose into glucose-6-phosphate. This "glucose trapping" mechanism keeps intracellular glucose levels low and promotes further glucose entry into the cell.
Which of the following is the correct sequence of enzyme activation in the pancreatic juice?
1) Trypsinogen -> Chymotrypsinogen -> Procarboxypeptidase A -> Proelastase
2) Enterokinase -> Trypsinogen -> Trypsin -> Chymotrypsinogen -> Chymotrypsin
3) Procarboxypeptidase B -> Chymotrypsinogen -> Trypsin -> Procarboxypeptidase A
4) Proelastase -> Chymotrypsinogen -> Chymotrypsin -> Trypsinogen
E) Trypsin -> Chymotrypsinogen -> Chymotrypsin -> Procarboxypeptidase A
The activation of pancreatic enzymes involves a cascade. Enterokinase, an enzyme present in the brush border of the small intestinal epithelial cells, first cleaves trypsinogen into active trypsin. Trypsin then cleaves chymotrypsinogen into chymotrypsin. This process continues with chymotrypsin activating proelastase and procarboxypeptidase A and B into their respective active forms, which are essential for the complete breakdown of proteins in the small intestine.