Nokea
Which cells myelinate neurons in the CNS?
- A. Schwann cells
- B. Astrocytes
- C. Microglia
- D. Oligodendrocytes
Correct Answer: D
Rationale: The correct answer is D, Oligodendrocytes. Oligodendrocytes are responsible for myelinating neurons in the central nervous system (CNS). Schwann cells, found in the peripheral nervous system, are responsible for myelinating neurons there. Astrocytes support and maintain the neuronal environment, while microglia function as immune cells in the CNS, participating in immune responses and cellular debris clearance. Therefore, choices A, B, and C are incorrect for myelination of CNS neurons.
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What is the atomic number of an atom?
- A. The number of protons in an atom
- B. The number of neutrons in an atom
- C. The number of electrons in an atom
- D. The sum of protons and neutrons
Correct Answer: A
Rationale: The correct answer is A: The atomic number of an atom is the number of protons in its nucleus. This number uniquely identifies the element, as each element has a distinct number of protons. Neutrons and electrons play roles in the atom's structure and stability, but the atomic number specifically refers to the number of protons. Choice B (The number of neutrons in an atom) is incorrect because the atomic number does not include neutrons; it only represents the number of protons. Choice C (The number of electrons in an atom) is incorrect because the atomic number is not related to the number of electrons, which can vary in different atomic configurations. Choice D (The sum of protons and neutrons) is incorrect because it refers to the mass number of an atom, which is the total number of protons and neutrons in the nucleus, not just the protons.
Which of the following is NOT a function of the forebrain?
- A. To regulate blood pressure and heart rate
- B. To perceive and interpret emotional responses like fear and anger
- C. To perceive and interpret visual input from the eyes
- D. To integrate voluntary movement
Correct Answer: A
Rationale: The correct answer is A. The forebrain is primarily responsible for higher cognitive functions such as perception, interpretation, and integration of sensory information, emotional responses, and voluntary movements. Functions like regulating blood pressure and heart rate are mainly controlled by various structures in the brainstem, such as the medulla oblongata and the pons. Choices B, C, and D are all functions associated with the forebrain. Choice B relates to the limbic system, which is part of the forebrain responsible for emotional responses. Choice C corresponds to the occipital lobe in the forebrain, involved in processing visual information. Choice D involves the motor cortex and other areas in the forebrain that coordinate voluntary movements.
Smooth muscle is the only ____________ muscle in the body.
- A. Voluntary, striated
- B. Involuntary, non-striated
- C. Involuntary, striated
- D. Voluntary, non-striated
Correct Answer: B
Rationale: Smooth muscle is the only involuntary, non-striated muscle type in the body. It is found in organs like the intestines and blood vessels, where it controls movements without conscious effort. Choice A is incorrect because voluntary muscles are under conscious control, while smooth muscle is involuntary. Choice C is incorrect because striations are not present in smooth muscle, unlike skeletal muscle. Choice D is incorrect because smooth muscle is not voluntary and lacks striations, making it different from skeletal muscle.
What are the four types of cells in the gastric glands of the stomach mucosa?
- A. Endocrine, parietal, chief, mucous cells
- B. Parietal, mucous, goblet, endocrine cells
- C. Chief, parietal, goblet, lymphoid cells
- D. Goblet, lymphoid, parietal, chief cells
Correct Answer: A
Rationale: The correct answer is A: Endocrine, parietal, chief, mucous cells. In the gastric glands of the stomach mucosa, the four types of cells are endocrine (producing hormones), parietal (secreting acid and intrinsic factor), chief (responsible for producing digestive enzymes), and mucous cells (providing protection to the stomach lining). These cells play essential roles in the digestive processes and maintaining the health of the stomach mucosa. Choices B, C, and D are incorrect because they do not accurately represent the types of cells found in the gastric glands of the stomach mucosa. Parietal cells secrete acid and intrinsic factor, chief cells produce digestive enzymes, and mucous cells provide protection, making these the correct choices in the context of gastric gland cellular composition.
What is the purpose of a catalyst?
- A. To increase a reaction rate by increasing the activation energy
- B. To increase a reaction rate by increasing the temperature
- C. To increase a reaction rate by decreasing the activation energy
- D. To increase a reaction rate by decreasing the temperature
Correct Answer: C
Rationale: The purpose of a catalyst is to increase a reaction's rate by decreasing the activation energy required for the reaction to occur. This allows the reaction to proceed more quickly without being consumed in the process. The catalyst provides an alternate mechanism with a lower activation energy, making it easier for the reactants to convert into products. Choice A is incorrect because a catalyst lowers, not increases, the activation energy. Choice B is incorrect because a catalyst does not affect the temperature directly but provides an alternative pathway for the reaction to occur more easily. Choice D is incorrect because a catalyst does not lower the temperature but facilitates the reaction by lowering the activation energy barrier. Therefore, the correct answer is C, 'To increase a reaction rate by decreasing the activation energy.'