Which of the following is a consequence of bone marrow failure?
- A. Seizures.
- B. Pancytopenia.
- C. Paraplegia.
- D. Pathologic fractures.
Correct Answer: B
Rationale: The corrected question focuses on the consequence of bone marrow failure, which is pancytopenia. Bone marrow failure results in decreased production of red blood cells, white blood cells, and platelets, leading to pancytopenia. This condition manifests as fatigue, weakness, increased infection susceptibility, and bleeding tendencies. Paraplegia, seizures, and pathologic fractures are not typical outcomes of bone marrow failure. Paraplegia is associated with spinal cord injury, seizures with neurological disorders, and pathologic fractures with conditions like osteoporosis or bone tumors.
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Which of the following terms means toward the front of the body?
- A. Superior
- B. Anterior
- C. Inferior
- D. Posterior
Correct Answer: B
Rationale: The correct answer is B: Anterior. The term 'anterior' specifically refers to the front of the body. In anatomical terms, anterior is the opposite of posterior, which means toward the back of the body. Superior and inferior, choices A and C, respectively, refer to top and bottom directions, not front and back. Therefore, 'Anterior' is the most appropriate term for describing a position toward the front of the body.
Which of the following organs is NOT part of the circulatory system?
- A. Kidneys
- B. Heart
- C. Blood
- D. Blood vessels
Correct Answer: A
Rationale: The correct answer is A: Kidneys. The kidneys are not part of the circulatory system. While the circulatory system includes the heart, blood, and blood vessels (arteries, veins, capillaries), the kidneys belong to the urinary system. The kidneys are responsible for filtering waste products from the blood and producing urine. Choice B, the heart, is a vital organ in the circulatory system responsible for pumping blood. Choice C, blood, is a key component of the circulatory system that carries oxygen and nutrients to the body's tissues. Choice D, blood vessels (arteries, veins, capillaries), facilitate the circulation of blood throughout the body, playing a crucial role in the circulatory system.
Which of the following is NOT an example of a homeostatic mechanism?
- A. Shivering when the body temperature falls.
- B. Increasing heart rate when blood pressure is low.
- C. Weight gain when consuming excess calories.
- D. Secreting insulin to decrease blood sugar concentration.
Correct Answer: C
Rationale: Weight gain when consuming excess calories is not an example of a homeostatic mechanism. Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. The other options listed (A, B, and D) involve physiological responses aimed at restoring balance or stability within the body (e.g., regulating body temperature, blood pressure, and blood sugar levels). Shivering, increasing heart rate, and secreting insulin are mechanisms to counteract specific imbalances and maintain internal equilibrium. In contrast, weight gain due to excess calorie intake does not represent a specific regulatory mechanism but rather an outcome of energy imbalance. The body stores excess energy as fat rather than actively regulating a physiological parameter to restore balance.
Which of the following structures is the natural pacemaker of the heart?
- A. Sinoatrial node
- B. Submental node
- C. Atrioventricular node
- D. Scalene node
Correct Answer: A
Rationale: The sinoatrial (SA) node is often referred to as the natural pacemaker of the heart because it is a group of cells located in the right atrium responsible for initiating the electrical signals that coordinate the heart's contractions. The SA node sets the rate and rhythm of the heartbeats, making it a crucial component in the heart's function. The other options, Submental node, Atrioventricular node, and Scalene node, are not related to the regulation of the heart's electrical activity. The Submental node is a lymph node located under the chin, the Atrioventricular node is responsible for passing electrical signals from the atria to the ventricles, and the Scalene node does not exist in the context of the heart's electrical system.
Which statement is true regarding the process of digestion?
- A. Digestion of starch begins in the mouth.
- B. Amylase is produced by the stomach to help break down food in the upper intestine.
- C. The di- and tri-saccharides produced in early digestion are absorbed through the intestinal wall.
- D. Proteases are responsible for breaking down starches.
Correct Answer: A
Rationale: The statement 'Digestion of starch begins in the mouth' is correct. Salivary amylase, an enzyme produced in the salivary glands, initiates the breakdown of starch into simpler sugars like maltose in the mouth before further digestion in the stomach. This initial breakdown of starch is crucial in the digestion of carbohydrates, marking the beginning of the digestive process. Choice B is incorrect because amylase is produced in the salivary glands, not the stomach. Choice C is incorrect because di- and tri-saccharides are further broken down into monosaccharides before absorption. Choice D is incorrect because proteases are enzymes that break down proteins, not starches.