MDS PREP
Which hormone binding protein is increased during pregnancy?
1) Thyroxine binding globulin (TBG)
2) Thyroxine binding albumin
3) Thyroxine binding prealbumin
4) All of the above
Answer: 1) Thyroxine binding globulin (TBG) is increased during pregnancy, which is a major thyroid hormone binding protein in the plasma.
What is the primary mechanism of bicarbonate reabsorption in the proximal convoluted tubule?
1) Passive diffusion
2) Active transport
3) Combination with hydrogen ions
4) Co-transport with sodium
The primary mechanism of bicarbonate reabsorption in the proximal convoluted tubule involves combination with hydrogen ions, forming carbonic acid, which is then converted to water and carbon dioxide.
What is the role of calbindin in calcium absorption in the intestine?
1) It sequesters calcium in the intestinal lumen
2) It transports calcium across the brush border membrane
3) It binds calcium and prevents it from affecting epithelial signaling
4) It stimulates the release of calcium from the intestinal cells into the bloodstream
Physiology
Answer: 3
Calbindin sequesters calcium within the intestinal epithelial cells to prevent it from interfering with calcium-dependent signaling processes, thereby facilitating efficient calcium absorption without disrupting normal cellular function.
Which cranial nerve is involved in the parasympathetic innervation of the lacrimal gland and pupillary constriction?
1) Cranial nerve III (Oculomotor)
2) Cranial nerve VII (Facial)
3) Cranial nerve X (Vagus)
4) Cranial nerve V (Trigeminal)
The vagus nerve, also known as the tenth cranial nerve, provides the parasympathetic innervation to various organs, including the lacrimal gland for tear production and pupillary constriction via the ciliary ganglia.
Which of the following is NOT a hormone produced by the kidneys?
1) Renin
2) Erythropoietin
3) Aldosterone
4) 1,25 Dihydrocholecalciferol
Aldosterone is NOT a hormone produced by the kidneys; it is produced by the adrenal glands and acts on the kidneys to regulate sodium and potassium balance.
What is the effect of increased parathyroid hormone during pregnancy?
1) Decreased calcium ion liberation from maternal bones
2) Increased calcium ion absorption in the gut
3) Increased calcium ion excretion in the urine
4) Increased calcium ion mobilization from maternal bones for fetal use
Answer: 4) Increased parathyroid hormone during pregnancy stimulates liberation of calcium ions from maternal bones for the fetus's calcium needs.
What is the primary function of the gastric inhibitory polypeptide (GIP)?
1) Stimulating gastric acid secretion
2) Inhibiting gastric acid secretion
3) Stimulating insulin secretion
4) Inhibiting insulin secretion
E) Stimulating gastric emptying
GIP is released from the K cells of the duodenum and jejunum in response to the presence of nutrients, particularly glucose and fat. Its primary function is to stimulate insulin secretion from the pancreatic beta cells, which helps regulate postprandial blood glucose levels. It also inhibits gastric acid secretion and gastric emptying.
What is the primary function of the parasympathetic nervous system during rest and digest conditions?
1) Stimulation of the heart and increased cardiac output
2) Constriction of blood vessels in the GI tract
3) Diverting blood flow to skeletal muscles
4) Decreasing heart rate and promoting gastrointestinal activity
Answer: 4) Decreasing heart rate and promoting gastrointestinal activityExplanation: The parasympathetic nervous system is responsible for the "rest and digest" functions. It slows the heart rate, constricts pupils, and stimulates digestive processes such as increased salivation, gastric acid secretion, and gastrointestinal motility.