Nokea
Which region of the small intestine is the primary site of absorption?
- A. Duodenum
- B. Jejunum
- C. Ileum
- D. Cecum
Correct Answer: B
Rationale: The jejunum is the correct answer. It is the primary site of nutrient absorption in the small intestine. The duodenum mainly facilitates digestion, the ileum is responsible for further absorption, while the cecum is part of the large intestine and not involved in nutrient absorption.
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Which structure in the lungs is the site of gas exchange?
- A. Trachea
- B. Alveoli
- C. Bronchioles
- D. Diaphragm
Correct Answer: B
Rationale: The correct answer is B: Alveoli. Alveoli are tiny air sacs in the lungs where gas exchange occurs. Oxygen from inhaled air diffuses into the bloodstream, while carbon dioxide from the blood is released into the alveoli to be exhaled. The trachea (Choice A) is the windpipe that carries air to and from the lungs, but it is not involved in gas exchange. Bronchioles (Choice C) are small air passages within the lungs that branch off from the bronchi, leading air to the alveoli but not directly involved in gas exchange. The diaphragm (Choice D) is a muscle below the lungs that helps in breathing by expanding and contracting the chest cavity, but it is not the site of gas exchange.
Which part of the cell is responsible for storing genetic information?
- A. Ribosome
- B. Mitochondrion
- C. Nucleus
- D. Cytoplasm
Correct Answer: C
Rationale: The correct answer is C, Nucleus. The nucleus is responsible for storing genetic information in the form of DNA. The DNA within the nucleus controls the activities of the cell by directing the synthesis of proteins and regulating gene expression. Choices A, Ribosome, B, Mitochondrion, and D, Cytoplasm, do not store genetic information. Ribosomes are involved in protein synthesis, mitochondria produce energy for the cell, and cytoplasm is a gel-like substance that houses organelles and where many cellular activities occur.
Which of the following is responsible for maintaining homeostasis in the body?
- A. Brainstem
- B. Hypothalamus
- C. Medulla oblongata
- D. Cerebrum
Correct Answer: B
Rationale: The correct answer is the Hypothalamus (choice B). The hypothalamus plays a crucial role in maintaining homeostasis by regulating various bodily functions such as hunger, thirst, body temperature, and sleep cycles. While the brainstem (choice A) is involved in basic life functions like breathing and heart rate, it is not primarily responsible for maintaining homeostasis. The medulla oblongata (choice C) is part of the brainstem and controls vital autonomic functions like breathing and heart rate, but it is not the main regulator of homeostasis. The cerebrum (choice D) is responsible for higher brain functions such as thinking, memory, and voluntary movement, but it is not directly involved in maintaining overall bodily balance or homeostasis.
Which of the following is a function of the kidneys?
- A. To produce digestive enzymes
- B. To filter waste from the blood
- C. To produce white blood cells
- D. To produce red blood cells
Correct Answer: B
Rationale: The correct answer is B: 'To filter waste from the blood.' The kidneys are vital organs responsible for filtering waste products from the blood, regulating fluid and electrolyte balance, and producing urine. Choice A is incorrect because the production of digestive enzymes primarily occurs in the pancreas and salivary glands. Choice C is incorrect as the production of white blood cells mainly takes place in the bone marrow and lymphatic system. Choice D is incorrect as the production of red blood cells occurs in the bone marrow.
What does the P-wave in an ECG correspond to?
- A. Atrial repolarization
- B. Depolarization of SA node
- C. Ventricular depolarization
- D. Ventricular repolarization
Correct Answer: B
Rationale: The P-wave in an ECG represents the depolarization of the SA node and the atria, not atrial repolarization. Choice C, ventricular depolarization, is incorrect because the P-wave does not correspond to ventricular activity. Choice D, ventricular repolarization, is also incorrect as the P-wave does not depict ventricular repolarization. The correct interpretation is that the P-wave signifies the initiation of the electrical impulse at the SA node and subsequent atrial depolarization, making option B the correct answer.