Medical Physiology Paper I — Exam III, OmpathStudy

Continued from $1. Question 51 The presentation of a bolus of solid food to the mouth: A) Stimulates taste buds B) Is usually followed by mastication C) Reflexively stimulates salivary glands D) All are correct Answer: D) All are correct Explanation: When food enters the mouth, it stimulates taste buds (gustatory), initiates mastication (chewing), and reflexively stimulates salivary glands through both tactile and taste stimuli. All these responses occur simultaneously. --- Question 52 The salivary secretion: A) Has a serous component B) Has a mucous component C) A and B are correct D) It is largely under hormonal control E) A, B and D are correct Answer: C) A and B are correct Explanation: Saliva has both serous (watery, enzyme-rich) and mucous (viscous, lubricating) components. However, salivary secretion is primarily under neural control (parasympathetic stimulation), not hormonal control. --- Question 53 The salivary secretion: A) Is stimulated by most GIT hormones specially gastrin B) Is essential for complete digestion of starch C) Increases more by sweet than by bitter substances D) Is markedly increased by parasympathetic stimulation E) Contains lower concentration of K+ & HCO3- than those in the plasma Answer: D) Is markedly increased by parasympathetic stimulation Explanation: Parasympathetic stimulation (via facial and glossopharyngeal nerves) markedly increases salivary secretion. Saliva actually contains higher concentrations of K+ and HCO3- than plasma, and bitter substances stimulate more saliva than sweet substances. --- Question 54 Salivation can become a conditioned reflex. This suggests that: A) Pleasant taste sensations are not related to the reflex B) Only salivatory nuclei in the brainstem need to be excited by taste sensation without participation of suprasegmental influences C) The cerebral cortex partially controls salivation D) Salivation could be completely interrupted in a decorticate animal whose tongue is mechanically stimulated Answer: C) The cerebral cortex partially controls salivation Explanation: The fact that salivation can be conditioned (like Pavlov's dogs) indicates cerebral cortex involvement in salivary control. Higher brain centers can influence the brainstem salivatory nuclei through learned associations. --- Question 55 Chronic gastritis is often associated with the following: A) Microcytic anemia B) Hyperchlorhydria C) Steatorrhea D) Pernicious anemia Answer: D) Pernicious anemia Explanation: Chronic gastritis, especially atrophic gastritis, destroys parietal cells that produce intrinsic factor. This leads to vitamin B12 deficiency and pernicious anemia (megaloblastic anemia), not microcytic anemia. --- Question 56 Vitamin B12 absorption: A) Depends on presence of intrinsic factor B) Depends on passive diffusion C) Occurs in the jejunum D) Occurs in the stomach Answer: A) Depends on presence of intrinsic factor Explanation: Vitamin B12 absorption requires intrinsic factor (produced by parietal cells) and occurs in the terminal ileum, not jejunum or stomach. It's an active process, not passive diffusion. --- Question 57 The secretion of the intrinsic factor occurs in: A) Parietal cells of the stomach B) Chief cells of the stomach C) Upper duodenum D) Beta cells of pancreas E) Liver Answer: A) Parietal cells of the stomach Explanation: Intrinsic factor is secreted by parietal cells in the gastric fundus and body, along with hydrochloric acid. Chief cells secrete pepsinogen, not intrinsic factor. --- Question 58: Hunger Pangs Question: So-called hunger pangs: a. Are truly due to smooth muscle spasm of the transverse colon b. Are associated with esophageal and pyloric contraction that coexist with an empty relaxed stomach c. Are more common if starvation is associated with hypoglycemia d. May occur in a totally vagotomized patient Answer: d. May occur in a totally vagotomized patient Explanation: Hunger pangs are contractions of the empty stomach that can occur even after vagotomy because they are primarily controlled by intrinsic gastric mechanisms and hormonal factors, not just vagal innervation. The other options are incorrect as hunger pangs originate from the stomach, not the colon, and are not necessarily associated with esophageal contractions or hypoglycemia. --- Question 59: Basal Acid Output Question: Basal acid output is increased with which of the following: a. Acidification of the antrum b. Administration of a H₂ receptor antagonist c. Vagotomy d. Alkalinization of the antrum e. Acidification of the duodenum Answer: d. Alkalinization of the antrum Explanation: Alkalinization of the antrum stimulates gastrin release, which increases basal acid output. Acidification of the antrum inhibits gastrin release through negative feedback. H₂ receptor antagonists and vagotomy both decrease acid output. --- Question 60: Cephalic Phase of Gastric Secretion Question: The cephalic phase of gastric secretion: A. Occurs when food reaches the stomach B. Is controlled by t