MDS PREP
Which of the following structures is associated with the control of voluntary eye movement?
1) Occipital lobe
2) Temporal lobe
3) Frontal eye field
4) Parietal lobe
The frontal eye field, located in the dorsolateral part of the frontal lobe, is involved in the control of voluntary eye movement. It is part of the motor system and helps in the planning and execution of saccadic movements.
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.
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
Neutralization of stomach acid is NOT an action of bile salts; bile salts primarily emulsify fats and facilitate fat absorption.
What is the role of ghrelin in the control of food intake?
1) It stimulates the release of growth hormone
2) It suppresses the secretion of gastric acid
3) It inhibits food intake
4) It increases the sensation of hunger
Ghrelin increases the sensation of hunger, stimulating appetite and food intake, particularly before meals.
Which sleep stage is associated with the lowest body temperature, decreased heart rate, and decreased muscle tone?
1) Stage 1 NREM
2) Stage 2 NREM
3) Stage 3 NREM
4) REM sleep
Stage 3 NREM, also known as slow-wave sleep, is characterized by delta waves on EEG and is associated with the lowest body temperature, decreased heart rate, and decreased muscle tone, indicating a deep restorative sleep state.
What is the role of Secretin in pancreatic enzyme secretion?
1) It directly stimulates the release of pancreatic enzymes.
2) It inhibits the release of pancreatic enzymes.
3) It has no effect on pancreatic enzyme secretion.
4) It augments the action of CCK in producing pancreatic enzyme secretion.
Secretin augments the action of CCK (cholecystokinin) in producing pancreatic enzyme secretion, facilitating digestion.
What is the primary mechanism of the inhibitory postsynaptic potential (IPSP) in the nervous system?
1) Activation of sodium channels causing depolarization
2) Activation of potassium channels causing hyperpolarization
3) Activation of chloride channels causing depolarization
4) Activation of calcium channels causing hyperpolarization
Answer: 2) Activation of potassium channels causing hyperpolarizationExplanation: IPSPs are typically generated when a neurotransmitter binds to GABA receptors on the postsynaptic membrane of a neuron, causing potassium channels to open and leading to efflux of K+ ions. This hyperpolarizes the neuron, reducing the likelihood of an action potential.
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.