MDS PREP
In which part of the nephron does the majority of bicarbonate reabsorption occur?
1) Glomerulus
2) Proximal Convoluted Tubule (PCT)
3) Loop of Henle
4) Collecting Duct
The majority of bicarbonate reabsorption occurs in the Proximal Convoluted Tubule (PCT), which is essential for maintaining acid-base balance.
What is the relationship between serum bilirubin levels and the appearance of sclera icterus?
1) Sclera icterus occurs when serum bilirubin levels are below 51 ?mol/L (3.0 mg/dL).
2) Sclera icterus occurs when serum bilirubin levels are at least 51 ?mol/L (3.0 mg/dL).
3) Sclera icterus occurs when serum bilirubin levels are above 100 ?mol/L (6.0 mg/dL).
4) Sclera icterus is not related to serum bilirubin levels.
Sclera icterus occurs when serum bilirubin levels are at least 51 ?mol/L (3.0 mg/dL), indicating jaundice.
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 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.
What is the role of the acrosome in sperm?
1) Provides energy for sperm motility
2) Contains enzymes that help in the penetration of the ovum
3) Protects the sperm DNA
4) Involved in the fertilization process by fusing with the egg membrane
The acrosome in sperm contains enzymes that help in the penetration of the ovum during fertilization, facilitating the fusion of sperm and egg.
What is the result of increased sympathetic nervous system activity on sodium and water reabsorption in the kidney?
1) Decreased sodium and water reabsorption
2) Increased sodium and water reabsorption in the PCT
3) Increased sodium and water reabsorption in the DCT
4) Decreased sodium and water reabsorption in the collecting ducts
E) No effect on sodium and water reabsorption
Sympathetic activity enhances sodium and water reabsorption in the PCT (proximal convoluted tubule) through increased activity of sodium pumps and sodium-potassium-2-chloride cotransporters, which helps in fluid and electrolyte retention.
What is the significance of the blood-brain barrier being absent in the circumventricular organs?
1) Allows free passage of hormones and neurotransmitters to the cerebrospinal fluid (CSF)
2) Enables direct interaction with the hypothalamus for osmoregulation
3) Facilitates the entry of pathogens and drugs into the brain
4) Necessary for the synthesis of neurotransmitters in these areas
The absence of the blood-brain barrier in circumventricular organs allows for the unimpeded movement of substances between the blood and the CSF, which is crucial for the regulation of various physiological processes, including osmoregulation.
What is the role of the corpus luteum in the second half of the menstrual cycle?
1) It secrets FSH
2) It secrets LH
3) It secrets estrogen and progesterone
4) It secrets inhibin
The corpus luteum secretes estrogen and progesterone during the second half of the menstrual cycle, which are essential for maintaining the uterine lining.