Nokea
Which part of the neuron is responsible for transmitting signals away from the cell body and toward other neurons or muscles?
- A. Axon
- B. Dendrite
- C. Synapse
- D. Myelin sheath
Correct Answer: A
Rationale: The axon is the part of the neuron responsible for transmitting signals away from the cell body and toward other neurons or muscles. It is a long, slender projection covered by the myelin sheath, which speeds up signal transmission. Dendrites, on the other hand, receive signals from other neurons and transmit them toward the cell body. The synapse is the junction between two neurons where communication occurs, but it is not responsible for transmitting signals away from the cell body.
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In the context of the cardiac cycle, what does the P wave on an electrocardiogram (ECG) represent?
- A. Atrial depolarization
- B. Ventricular depolarization
- C. Atrial repolarization
- D. Ventricular repolarization
Correct Answer: A
Rationale: The P wave on an electrocardiogram (ECG) represents atrial depolarization, which signifies the electrical activation of the atria as they prepare to contract. During the cardiac cycle, atrial depolarization occurs first, leading to atrial contraction. Ventricular depolarization is represented by the QRS complex, not the P wave. Choices B, C, and D are incorrect because the P wave specifically corresponds to atrial depolarization, not ventricular depolarization, atrial repolarization, or ventricular repolarization.
Which vitamin is synthesized in the skin upon exposure to sunlight?
- A. Vitamin A
- B. Vitamin C
- C. Vitamin D
- D. Vitamin E
Correct Answer: C
Rationale: Vitamin D is synthesized in the skin upon exposure to sunlight. When the skin is exposed to sunlight, a form of cholesterol in the skin is converted into vitamin D3 (cholecalciferol) through a series of chemical reactions. Vitamin D plays a crucial role in calcium absorption and bone health. Choice A, Vitamin A, is not synthesized in the skin upon exposure to sunlight; it is obtained through dietary sources. Choice B, Vitamin C, is not synthesized in the skin upon exposure to sunlight either. Vitamin C is obtained through dietary sources like fruits and vegetables. Choice D, Vitamin E, is not synthesized in the skin upon exposure to sunlight. Vitamin E is a fat-soluble vitamin that acts as an antioxidant and is obtained through dietary sources like nuts, seeds, and vegetable oils.
The gland located on top of the kidneys responsible for regulating blood pressure and electrolyte balance is the:
- A. Thyroid gland
- B. Pituitary gland
- C. Adrenal gland
- D. Parathyroid gland
Correct Answer: C
Rationale: The gland located on top of the kidneys responsible for regulating blood pressure and electrolyte balance is the adrenal gland. The adrenal gland produces hormones such as cortisol and aldosterone, which play a crucial role in regulating blood pressure and electrolyte balance in the body. The other choices, thyroid gland (choice A), pituitary gland (choice B), and parathyroid gland (choice D), do not have a primary role in regulating blood pressure and electrolyte balance. The thyroid gland is responsible for regulating metabolism, the pituitary gland controls various endocrine functions, and the parathyroid gland regulates calcium levels in the body.
What is the building block of DNA?
- A. Amino acid
- B. Nucleotide
- C. Phosphate group
- D. Fatty acid
Correct Answer: B
Rationale: - Amino acids are the building blocks of proteins, not DNA.
- Nucleotide is the correct building block of DNA. A nucleotide consists of a sugar (deoxyribose in DNA), a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine).
- The option 'C) Phosphate group' is incorrect as it is only part of a nucleotide, not the complete building block of DNA.
- Fatty acids are not the building blocks of DNA; they are a type of lipid molecule.
What is the role of the hypothalamus in the body?
- A. To regulate digestion
- B. To regulate hormones
- C. To regulate body temperature
- D. To regulate the immune system
Correct Answer: B
Rationale: The correct answer is B: 'To regulate hormones.' The hypothalamus plays a crucial role in regulating hormones and maintaining homeostasis by controlling various functions such as hunger, thirst, body temperature, and sleep-wake cycles. While digestion, body temperature, and the immune system are important bodily functions, they are not primarily controlled by the hypothalamus. Therefore, choices A, C, and D are incorrect as they do not accurately represent the primary function of the hypothalamus.