HESI A2
HESI A2 Anatomy and Physiology Practice Test
1. What is the primary hormone secreted by the thyroid gland?
- A. Oxytocin
- B. TSH
- C. Adrenaline
- D. T4
Correct answer: D
Rationale: The correct answer is D: T4. The primary hormone secreted by the thyroid gland is thyroxine, also known as T4. T4 plays a crucial role in regulating metabolism, growth, and energy levels in the body. It is converted into the more active form, triiodothyronine (T3), which exerts most of the biological effects of thyroid hormones. Choices A, B, and C are incorrect. Oxytocin is not produced by the thyroid gland but by the pituitary gland, TSH (thyroid-stimulating hormone) is secreted by the pituitary gland to stimulate the thyroid gland, and adrenaline is produced by the adrenal glands, not the thyroid gland.
2. Which vitamin is essential for the synthesis of collagen?
- A. Vitamin C
- B. Vitamin D
- C. Vitamin B12
- D. Vitamin K
Correct answer: A
Rationale: The correct answer is Vitamin C. Vitamin C is essential for the synthesis of collagen, a protein crucial for maintaining the structure and integrity of skin, blood vessels, and bones. It plays a key role in the hydroxylation of proline and lysine residues in collagen synthesis, which is necessary for the stability and strength of collagen fibers. Choice B: Vitamin D is essential for bone health and calcium absorption but is not directly involved in collagen synthesis. Choice C: Vitamin B12 is important for red blood cell formation and neurological function but is not directly related to collagen synthesis. Choice D: Vitamin K is necessary for blood clotting and bone metabolism but does not play a direct role in collagen synthesis.
3. Which neurotransmitter controls sleep, mood, and appetite?
- A. Serotonin
- B. Oxytocin
- C. Cortisol
- D. Aldosterone
Correct answer: A
Rationale: Serotonin is the correct answer. It is a neurotransmitter that plays a crucial role in regulating mood, sleep, and appetite. Serotonin functions to stabilize and control these physiological processes in the brain and body. Imbalances in serotonin levels are commonly linked to conditions like depression, anxiety, and eating disorders. Oxytocin (Choice B) is more associated with social bonding and childbirth. Cortisol (Choice C) is a stress hormone, and while it can influence mood and appetite in response to stress, it is not primarily responsible for regulating these functions. Aldosterone (Choice D) is a hormone that regulates electrolyte balance and blood pressure, not mood, sleep, and appetite.
4. Which hormone is responsible for the regulation of calcium levels in the blood?
- A. Insulin
- B. Parathyroid hormone
- C. Cortisol
- D. Melatonin
Correct answer: B
Rationale: Parathyroid hormone, produced by the parathyroid glands, is responsible for regulating calcium levels in the blood. It achieves this by increasing calcium absorption in the intestines and kidneys, thus maintaining appropriate calcium levels in the bloodstream. Insulin is involved in glucose metabolism, not calcium regulation. Cortisol is a stress hormone that affects various body functions but not calcium levels. Melatonin is responsible for regulating the sleep-wake cycle, not calcium levels.
5. What is the meaning of endocytosis?
- A. The cell engulfs solid particles.
- B. The cell engulfs liquid material.
- C. The cell expels solid particles.
- D. The cell releases liquid material.
Correct answer: A
Rationale: Endocytosis is a cellular process where the cell engulfs and internalizes solid particles by forming vesicles. It is a mechanism used for nutrient uptake, cell signaling, and maintaining cellular homeostasis. Options B, C, and D describe processes that are opposite to endocytosis. Choice B is incorrect because it describes pinocytosis, which is the process of engulfing liquid material. Choice C is incorrect as it describes exocytosis, the process of expelling material from the cell. Choice D is incorrect as it describes the process of releasing liquid material from the cell. Therefore, the correct answer is A.
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