MDS PREP
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.
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
Physiology
Answer: 4
Ghrelin is a hormone produced mainly by the stomach that stimulates appetite and food intake. It acts on the hypothalamus to increase hunger and is often referred to as the "hunger hormone." It also stimulates growth hormone secretion from the pituitary gland.
Most of the pre ganglionic sympathetic fibres are
1 A fibres
2 B fibres
3 C Fibres
4 None of the above
Physiology
Answer: 2
- A fibres are myelinated fibres having fastest rate of conduction
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.
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.
Which of the following statements about the neuronal circuit of the cerebellum is true?
1) Climbing fibers originate from the cerebral cortex and terminate on purkinje cells.
2) Mossy fibers establish excitatory synapses with interneurons in the molecular layer.
3) Stellate and basket cells are stimulated by inhibitory inputs from purkinje cells.
4) Golgi cells are inhibited by mossy fiber inputs.
E. All of the above.
Mossy fibers originate from various sources in the brain and spinal cord and terminate on granule cells in the granular layer of the cerebellum. The axons of granule cells, called parallel fibers, stimulate the purkinje cells and also synapse with interneurons such as stellate and basket cells in the molecular layer and Golgi cells in the granular layer. Climbing fibers originate from the inferior olivary nuclei and synapse directly on purkinje cells. The statement that stellate and basket cells are stimulated by inhibitory inputs from purkinje cells is incorrect; they are stimulated by parallel fibers and inhibit purkinje cells. Golgi cells are also stimulated by mossy fibers and help in the regulation of the overall output of the cerebellum.
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.
Which of the following is NOT a hormone secreted by the kidney?
1) 1,25 Dihydrocholecalciferol
2) Renin
3) Erythropoietin
4) Angiotensin I
Angiotensin I is NOT a hormone secreted by the kidney; it is produced from angiotensinogen in the liver and converted to angiotensin II by the kidneys.