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Free STEP1 Exam Braindumps (page: 62)

Page 61 of 213
PDF with 845 Questions

Which of the following shows the correct effects of hormones, when increased in serum, on liver glycogen content?

  1. A
  2. B
  3. C
  4. D
  5. E

Answer(s): C

Explanation:

Glucagon and catecholamines such as epinephrine stimulate the mobilization of glycogen by triggering the cAMP cascade. Hormones that increase liver cell cAMP promote glycogen breakdown, and hormones that decrease liver cell cAMP promote glycogen synthesis. Cortisol, the main glucocorticoid, regulates the metabolism of proteins, fats, and carbohydrates. It acts on most organs catabolically. However, on the liver it has anabolic effects, increasing glycogen synthesis and accumulation in the liver. Choices A, B, D, and E do not correctly reflect the effects of the three different agents on glycogen metabolism.



Opioid peptides are an important physiological mechanism of the body for relief from painful stimuli. Used as pharmacologic agents, they are highly valuable tools for pain management, although side effects are usually inevitable. Which of the following problems are most likely during opiate treatments?

  1. difficulty sleeping
  2. hypermotility of the GI tract
  3. placebo effects
  4. respiratory alkalosis
  5. tolerance (need for higher dosage to achieve the same therapeutic effect)

Answer(s): E

Explanation:

Tolerance is commonly observed with many pharmacologic agents, including opioids. Difficulty sleeping (choice A), hypermotility of the GI tract (choice B), and respiratory alkalosis (choice D) are opposite to the expected effect of opiates. The placebo effect (choice C) is, at least in part, likely due to the release of endogenous opioid peptides in anticipation of pain relief, but is not a complication or side effect of therapy.



Following an automobile accident a patient suffers a pelvic fracture and significant internal blood loss resulting in hemorrhagic shock. Which of the following organs has the largest specific blood flow (blood flow per gram of tissue) under resting conditions and is especially vulnerable during the shock phase?

  1. brain
  2. heart muscle
  3. kidneys
  4. skeletal muscle
  5. skin

Answer(s): C

Explanation:

During resting conditions, approximately 15% of the cardiac output goes to the brain, 15% to the muscles, 30% to the GI tract, and 20% to the kidneys. However, when normalized by organ weight, the kidneys receive the largest specific blood flow (400 mL/100 g) at rest and are particularly vulnerable during hemorrhagic shock. The brain (choice A) also receives relatively high specific blood flow (50 mL/100 g).
Heart muscle (choice B), not surprisingly, also has a relatively high resting specific blood flow (60 mL/100 g), which may increase fivefold during exercise. Skeletal muscles (choice D) have low specific blood flow (23 mL/100 g) at rest, which may increase up to 20-fold during strenuous exercise. Blood flow through the skin (choice E) varies between 1 and 100 ml/100 g and serves temperature regulation.



A 75-year-old male presented with a 6-month history of early satiety and with upper abdominal discomfort for many years. Physical examination revealed mild epigastric tenderness. Esophago-gastro- duodenoscopy showed a large, ulcerated mass in the upper stomach, which was found to be cancerous. Surgery resulting in the removal of the gastric fundus was performed. After successful surgery, the patient was advised to eat small portions and to drink small volumes because of which of the following?

  1. almost complete absence of gastric motility
  2. distorted emptying of liquids
  3. inadequate mixing of large food boluses
  4. lack of receptive relaxation in the stomach
  5. weaker and slower propulsion of food toward the pylorus

Answer(s): D

Explanation:

The receptive relaxation reflex is a feature of the orad stomach, composed of the fundus and upper stomach body. Without food, the orad stomach shows low frequency, sustained contractions that are responsible for generating a basal pressure within the stomach. When food enters the stomach, a reflex is initiated, which allows gastric accommodation of large increases in volume with only small increases in intragastric pressure. The tonic contractions of the orad stomach also contribute to some extent to gastric emptying (choice B), since they generate a pressure gradient from the stomach to the intestine. However, neural and hormonal components play a more important role in regulating gastric emptying, which makes this not the best choice. Since the lower stomach is not affected by the surgery, characteristic motility patterns of the distal stomach remain (choice A). Features of the distal stomach include strong peristaltic waves of contractions, which cause the mixing of the chyme with digestive secretions (choice C), the grinding of the particles to a small size, and the propulsion through the gastroduodenal junction (choice E).
All these motility patterns would still be a feature of the remaining stomach.






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