HESI A2
Quizlet HESI A2 Anatomy and Physiology
1. Which of the following is not a component of the central nervous system?
- A. Brain
- B. Heart
- C. Retina
- D. Spinal cord
Correct answer: B
Rationale: The central nervous system comprises the brain and spinal cord, responsible for processing and transmitting information. The retina, though part of the eye, is an extension of the central nervous system. However, the heart is part of the circulatory system, responsible for pumping blood throughout the body. Therefore, the correct answer is the heart as it is not a component of the central nervous system.
2. Which part of the eye is responsible for color vision?
- A. Cornea
- B. Iris
- C. Retina
- D. Lens
Correct answer: C
Rationale: The correct answer is option C: Retina. The retina contains photoreceptor cells, including cones that are responsible for color vision. Cones are sensitive to different wavelengths of light, allowing us to perceive and differentiate various colors. Choice A, Cornea, is the transparent outer layer of the eye that helps focus light. It does not play a direct role in color vision. Choice B, Iris, is the colored part of the eye that controls the size of the pupil and regulates the amount of light entering the eye. While it is essential for adjusting light levels, it is not directly involved in color vision. Choice D, Lens, is responsible for focusing light onto the retina. It helps to form clear images on the retina but does not play a role in color vision.
3. Which vitamin is essential for vision and skin health?
- A. Vitamin A
- B. Vitamin C
- C. Vitamin D
- D. Vitamin E
Correct answer: A
Rationale: Vitamin A is the correct answer. It is crucial for maintaining healthy vision and skin. Vitamin A plays a vital role in supporting normal vision, skin health, and immune function. Specifically, it is important for the health of the retina and is essential for the formation of rhodopsin, a protein in the retina necessary for low-light and color vision. Vitamin C (Choice B) is important for collagen synthesis and immune function, but it is not primarily associated with vision health. Vitamin D (Choice C) is crucial for bone health and immune function, while Vitamin E (Choice D) acts as an antioxidant, protecting cells from damage, but neither are primarily linked to vision and skin health like Vitamin A.
4. 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.
5. What is the primary function of the alveoli in the lungs?
- A. Removing carbon dioxide from the blood
- B. Exchanging oxygen and carbon dioxide
- C. Transporting oxygen to the bloodstream
- D. Filtering blood
Correct answer: B
Rationale: The primary function of the alveoli in the lungs is to exchange oxygen and carbon dioxide. The alveoli are tiny air sacs in the lungs responsible for this gas exchange during breathing. Oxygen diffuses from the inhaled air into the blood in the capillaries surrounding the alveoli, while carbon dioxide diffuses from the blood into the alveoli to be exhaled out of the body. Choice A is incorrect because the alveoli primarily facilitate the exchange of gases, not just the removal of carbon dioxide. Choice C is incorrect as the alveoli do not transport oxygen to the bloodstream but rather facilitate the exchange of gases. Choice D is incorrect as the alveoli are not involved in filtering blood but in gas exchange to ensure proper oxygenation and removal of carbon dioxide in the respiratory process.
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