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What is the role of the spleen in the immune system?
- A. To filter blood and remove old red blood cells
- B. To produce white blood cells
- C. To store lymphocytes
- D. To produce antibodies
Correct Answer: A
Rationale: The spleen plays a crucial role in the immune system by filtering blood, specifically removing old or damaged red blood cells. It also stores lymphocytes, which are white blood cells that help fight infections. While the spleen does not produce white blood cells or antibodies, its main functions lie in blood filtration and storage of immune cells. Therefore, the correct answer is A. Choice B is incorrect because the spleen does not produce white blood cells. Choice C is incorrect as the spleen stores lymphocytes but does not primarily function to do so. Choice D is incorrect because the spleen does not produce antibodies.
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Which of the following endocrine system glands releases the thyrotrophic-releasing hormone, growth hormone-releasing hormone, and gonadotropin-releasing hormones?
- A. Thymus
- B. Pituitary gland
- C. Pineal gland
- D. Hypothalamus
Correct Answer: D
Rationale: The correct answer is D, the Hypothalamus. The hypothalamus is responsible for releasing various essential hormones, including thyrotrophic-releasing hormone, growth hormone-releasing hormone, and gonadotropin-releasing hormones. These hormones play crucial roles in regulating the functions of other endocrine glands by stimulating or inhibiting their hormone production. The Thymus (choice A) is primarily involved in the immune system, the Pituitary gland (choice B) secretes various hormones but not the ones specified in the question, and the Pineal gland (choice C) mainly produces melatonin, which regulates sleep-wake cycles, and is not related to the hormones mentioned in the question.
Which of the following is known as the production of red blood cells?
- A. Thrombopoiesis
- B. Erythropoiesis
- C. Hematopoiesis
- D. Phagocytosis
Correct Answer: B
Rationale: Erythropoiesis specifically refers to the process of producing red blood cells (erythrocytes) in the bone marrow. Hematopoiesis is the broader term that encompasses the production of all types of blood cells, including red blood cells, white blood cells, and platelets. Phagocytosis is the process by which cells engulf and digest particles, while thrombopoiesis is the production of platelets. Therefore, the correct answer is B as it directly relates to the production of red blood cells.
Which of the following is an organ of the respiratory system?
- A. Pancreas
- B. Brain
- C. Urethra
- D. Larynx
Correct Answer: D
Rationale: The larynx is a vital organ of the respiratory system, responsible for producing sound and connecting the pharynx to the trachea. It plays a crucial role in breathing, swallowing, and vocalization. The brain, pancreas, and urethra are not part of the respiratory system; the brain is part of the nervous system, the pancreas is part of the digestive system, and the urethra is part of the urinary system. Therefore, the correct answer is the larynx.
Which cellular structure is responsible for producing energy?
- A. Nucleus
- B. Mitochondria
- C. Ribosome
- D. Golgi apparatus
Correct Answer: B
Rationale: Mitochondria are the organelles responsible for producing energy in the cell through a process called cellular respiration. They are often referred to as the powerhouses of the cell due to their role in generating ATP, the cell's energy currency. The nucleus is not involved in energy production but houses the cell's genetic material. Ribosomes are responsible for protein synthesis, not energy production. The Golgi apparatus is involved in processing and packaging proteins for secretion, not energy production.
Which of the following statements best describes endocrine glands?
- A. They absorb chemicals from the blood
- B. They secrete chemicals into the blood
- C. They filter chemicals from the blood
- D. They absorb chemicals from the lymphatic system
Correct Answer: B
Rationale: The correct answer is B: 'They secrete chemicals into the blood.' Endocrine glands release hormones directly into the bloodstream to regulate various body functions. This process helps in maintaining homeostasis and coordinating different physiological processes within the body. Choice A is incorrect as endocrine glands do not absorb chemicals from the blood; instead, they release hormones. Choice C is incorrect as endocrine glands do not filter chemicals from the blood; they secrete hormones. Choice D is incorrect as endocrine glands do not absorb chemicals from the lymphatic system; they release hormones into the bloodstream.