MDS PREP
Which part of the autonomic nervous system is responsible for the regulation of the visceral organs during rest and digestion?
1) Sympathetic nervous system
2) Parasympathetic nervous system
3) Enteric nervous system
4) Sensory nervous system
The parasympathetic nervous system is involved in the regulation of the body's rest and digest functions. It operates to conserve energy and restore the body to a state of equilibrium. It acts on various visceral organs, such as the heart, gastrointestinal tract, and bladder, to slow down the heart rate, increase glandular secretions, and promote peristalsis for food assimilation.
What is the primary role of the cephalic phase of gastric acid secretion?
1) Stimulation of gastrin release in the stomach
2) Secretion of gastric juices in response to the thought or smell of food
3) Increase in gastric motility
4) Secretion of gastric juices in response to food entering the duodenum
Physiology
Answer: 2
The cephalic phase of gastric acid secretion is initiated by the parasympathetic system and is triggered by the sight, smell, or thought of food. It accounts for approximately 20% of total acid secretion and prepares the stomach for digestion even before food arrives.
What is the primary mechanism of H+ secretion by parietal cells?
1) Active transport via the sodium-hydrogen exchanger (NHE3)
2) Secretion through H+-K+ ATPase pump
3) Secretion through a chloride-bicarbonate antiporter
4) Secretion through a sodium-bicarbonate cotransporter
E) Secretion through a sodium-hydrogen antiporter
The primary mechanism of H+ secretion by parietal cells is through the action of the H+-K+ ATPase pump, also known as the proton pump. This enzyme is responsible for actively transporting H+ ions into the gastric lumen while moving K+ ions into the cells, thereby acidifying the gastric content.
What is the primary visual area of the occipital lobe also known as?
1) Brodmann area 17
2) V1
3) Calcarine cortex
4) Striate cortex
The primary visual area is Brodmann area 17, which is located in the occipital lobe's medial side of the calcarine sulcus. It is also commonly referred to as the striate cortex due to the distinctive myelinated strip, the stria of Gennari.
What is the primary type of receptor involved in the sympathetic nervous system's response at the neuromuscular junction?
1) Muscarinic receptors
2) Nicotinic receptors
3) Alpha-1 receptors
4) Beta-2 receptors
Answer: 2) The primary type of receptor involved in the sympathetic nervous system's response at the neuromuscular junction is the nicotinic receptor, which is an intrinsic ligand-gated ion channel.
In which brain regions are Broca's and Wernicke's areas located?
1) Inferior temporal gyrus and superior parietal gyrus
2) Inferior frontal gyrus and superior temporal gyrus
3) Superior frontal gyrus and middle temporal gyrus
4) Inferior parietal lobule and superior occipital gyrus
Answer: 2) Broca's area is located in the inferior frontal gyrus and is involved in motor speech, while Wernicke's area is located in the superior temporal gyrus and is associated with language comprehension.
Which of the following is NOT a primary bile acid synthesized in the liver from cholesterol?
1) Cholic acid
2) Chenodeoxycholic acid
3) Deoxycholic acid
4) Lithocholic acid
Deoxycholic acid is NOT a primary bile acid synthesized in the liver from cholesterol; it is a secondary bile acid formed from the bacterial action on primary bile acids in the intestine.
What is the primary function of the pyloric sphincter?
1) To regulate the flow of chyme into the small intestine
2) To mix and churn food in the stomach
3) To secrete intrinsic factor for vitamin B12 absorption
4) To secrete mucus for the protection of the gastric mucosa
E) To produce hydrochloric acid
The pyloric sphincter, also known as the pylorus, is a ring of smooth muscle that connects the stomach to the duodenum. It relaxes to allow small, controlled amounts of chyme to pass from the stomach into the duodenum. This regulation is important to prevent the rapid emptying of the stomach and the potential overwhelming of the small intestine with food and acid.