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.
In the presence of which substance does vitamin B12 combine in the stomach to prevent its degradation by gastric acid?
1) Intrinsic factor
2) Pepsin
3) Gastric acid
4) Pancreatic amylase
In the presence of intrinsic factor, vitamin B12 combines in the stomach to prevent its degradation by gastric acid, ensuring its availability for absorption.
What is the role of the area postrema in the regulation of food intake?
1) It senses the presence of food in the stomach
2) It detects the nutritional content of food
3) It is involved in the detection of toxins and the initiation of vomiting
4) It directly stimulates the release of hunger hormones
The area postrema is part of the chemoreceptive trigger zone and detects the presence of toxins in the bloodstream, leading to the initiation of vomiting as a protective mechanism against the ingestion of harmful substances.
Which of the following is the correct statement regarding mammalian nerve fibers?
1) A-alpha fibers have the lowest conduction velocity and are responsible for pain and temperature sensation.
2) A-beta fibers have the highest conduction velocity and are responsible for motor supply to skeletal muscles.
3) A-gamma fibers are heavily myelinated and have the fastest conduction velocity.
4) C fibers have a large diameter and are responsible for fine motor control.
Answer: 2) A-beta fibers have the second highest conduction velocity after A-alpha fibers and are responsible for touch, kinesthetic sense, and pressure sensation, not motor supply to skeletal muscles. A-alpha fibers have the highest conduction velocity and are indeed responsible for motor supply to skeletal muscles.
What is the primary mechanism by which acid secretion is regulated in the stomach?
1) By the pH of the stomach content
2) By the amount of food present
3) By the time of day
4) By the type of food consumed
The primary mechanism by which acid secretion is regulated in the stomach is by the pH of the stomach content, which influences gastric secretions.
How does the cerebellum contribute to motor coordination?
1) By timing and comparing the duration of agonist muscle activity and latency of antagonist activity
2) By directly controlling the force of muscle contraction
3 ) By regulating the rate of nerve impulse conduction in motor neurons
4) By initiating voluntary movement
The cerebellum is crucial for the coordination of movement. It receives signals from the motor cortex about the intended movement and the actual position of the limb through climbing fibers. By timing these signals, it helps to stop the movement at the correct point by inhibiting the agonist muscles and stimulating the antagonist muscles.
What is the primary action of antidiuretic hormone (ADH) in the kidneys?
1) Increases the permeability of water in the proximal tubules
2) Increases the permeability of water in the collecting tubules and ducts
3) Stimulates glomerular filtration rate
4) Inhibits sodium reabsorption
The primary action of antidiuretic hormone (ADH) in the kidneys is to increase the permeability of water in the collecting tubules and ducts, promoting water reabsorption.
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.