HESI A2
HESI A2 Anatomy and Physiology Practice Exam
1. Which of the following is not part of the body’s secondary defense system?
- A. Macrophages
- B. Leukocytes
- C. T cells
- D. Cilia
Correct answer: D
Rationale: Cilia are not part of the body's secondary defense system. They are hair-like structures primarily involved in movement and transporting substances across cell surfaces, such as in the respiratory tract for debris and pathogen removal. However, cilia do not play a direct role in the immune response mechanisms characteristic of the body's secondary defense system. Macrophages, leukocytes, and T cells are immune cells that actively participate in the secondary defense system by targeting and eliminating pathogens.
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. To which system do the retinas belong?
- A. skeletal system
- B. nervous system
- C. lymphatic system
- D. circulatory system
Correct answer: B
Rationale: The retinas belong to the nervous system. The retina is a layer of tissue at the back of the eye responsible for detecting light and sending visual information to the brain through the optic nerve. This process is essential for vision, which is controlled by the nervous system. Choices A, C, and D are incorrect because the retinas have no association with the skeletal, lymphatic, or circulatory systems.
4. Which hormone is responsible for regulating blood sugar levels?
- A. Insulin
- B. Glucagon
- C. Thyroxine
- D. Melatonin
Correct answer: A
Rationale: Insulin, produced by the pancreas, is the hormone responsible for regulating blood sugar levels. It works by facilitating the uptake of glucose into cells, helping to lower blood sugar levels. Glucagon, on the other hand, works to increase blood sugar levels by promoting the release of glucose from the liver. Thyroxine is a hormone produced by the thyroid gland that regulates metabolism. Melatonin, a hormone that helps regulate sleep-wake cycles, is not responsible for regulating blood sugar levels. Therefore, the correct answer is insulin.
5. Which gland regulates the body's metabolic rate?
- A. Pituitary gland
- B. Thyroid gland
- C. Adrenal gland
- D. Pineal gland
Correct answer: B
Rationale: The thyroid gland is responsible for regulating the body's metabolic rate by producing hormones such as thyroxine (T4) and triiodothyronine (T3). These hormones play a crucial role in controlling the body's metabolism, affecting processes like growth, energy production, and temperature regulation. The pituitary gland is known as the 'master gland' but primarily regulates other endocrine glands by releasing hormones that stimulate their function. The adrenal gland is responsible for producing hormones like adrenaline and cortisol, which are involved in the body's response to stress. The pineal gland secretes melatonin, a hormone that regulates sleep-wake cycles and circadian rhythms, but is not directly involved in regulating metabolic rate.
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