MDS PREP
What is the function of the enteric nervous system?
1) Controls the heart rate and rhythm
2) Regulates the contraction of skeletal muscles
3) Regulates the function of the gastrointestinal tract
4) Controls the pupillary response to light
The enteric nervous system is the intrinsic nervous system of the gastrointestinal tract and is responsible for the regulation of digestion and other gastrointestinal functions. It can operate independently of the central nervous system and consists of a network of neurons and glial cells that are embedded within the wall of the gut, coordinating local reflexes and influencing the muscle and secretory activities of the digestive system.
What is the role of the acrosome in sperm penetration of the egg during fertilization?
1) It produces energy for the sperm's movement
2) It contains enzymes that help dissolve the egg's outer layers
3) It transfers genetic material to the egg
4) It has no role in the penetration process
The acrosome in sperm contains enzymes that help dissolve the egg's outer layers, facilitating sperm penetration during fertilization.
What is the primary mechanism of sodium reabsorption in the distal convoluted tubule and collecting ducts?
1) Passive diffusion
2) Active transport with sodium-potassium ATPase pump
3) Facilitated diffusion
4) Countercurrent exchange with hydrogen ions
The primary mechanism of sodium reabsorption in the distal convoluted tubule and collecting ducts is active transport with the sodium-potassium ATPase pump.
What is the primary function of the juxtaglomerular apparatus (JGA)?
1) Regulation of blood volume and blood pressure
2) Formation of urine
3) Secretion of renin
4) Concentration of urine
The primary function of the juxtaglomerular apparatus (JGA) is the secretion of renin, which regulates blood volume and blood pressure.
What is the primary function of bile acids in the intestine?
1) Emulsification of dietary fat
2) Neutralization of intestinal pH
3) Digestion of proteins
4) Absorption of water and electrolytes
The primary function of bile acids in the intestine is the emulsification of dietary fat, which aids in fat digestion and absorption.
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 the sodium-calcium exchanger (NCX) in calcium homeostasis?
1) It transports calcium into cells
2) It transports sodium into cells and calcium out of cells
3) It transports sodium out of cells and calcium into cells
4) It has no role in calcium homeostasis
Physiology
Answer: 3
The sodium-calcium exchanger (NCX) is involved in the regulation of calcium levels in cells. It exchanges three sodium ions (Na+) for one calcium ion (Ca2+), thereby helping to maintain intracellular calcium homeostasis.
What is the role of antidiuretic hormone (ADH) in the nephron?
1) Increases sodium reabsorption
2) Increases water reabsorption
3) Decreases potassium secretion
4) Inhibits renin secretion
Antidiuretic hormone (ADH) increases water reabsorption in the nephron, particularly in the collecting ducts, by making them more permeable to water.