HESI A2
HESI A2 Anatomy and Physiology 2023
1. 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.
2. Which vitamin is essential for bone health?
- A. Vitamin A
- B. Vitamin D
- C. Vitamin C
- D. Vitamin K
Correct answer: B
Rationale: Vitamin D is the correct answer. It is essential for bone health as it helps in the absorption of calcium, a crucial mineral for maintaining strong and healthy bones. Adequate levels of Vitamin D are necessary to prevent conditions like osteoporosis and ensure optimal bone development and strength. Choice A, Vitamin A, is important for vision and immune function, but it is not directly related to bone health. Choice C, Vitamin C, is essential for collagen synthesis and immune function, but it is not primarily responsible for bone health. Choice D, Vitamin K, plays a role in blood clotting and bone metabolism, but Vitamin D has a more direct impact on bone health through its role in calcium absorption.
3. What is the role of the mitochondria in the cell?
- A. Protein synthesis
- B. Energy production
- C. Breaking down waste
- D. Cell division
Correct answer: B
Rationale: The correct answer is B: Energy production. Mitochondria are known as the powerhouses of the cell because they generate adenosine triphosphate (ATP) through the process of cellular respiration. ATP is a molecule that stores and releases energy, providing the cell with the necessary energy for various activities and functions. Choices A, C, and D are incorrect. Protein synthesis primarily occurs in the ribosomes, breaking down waste is mainly carried out by lysosomes, and cell division is orchestrated by the nucleus and other organelles like the centrioles.
4. Which hormone is produced by the pineal gland?
- A. Corticosteroid
- B. Oxytocin
- C. Prolactin
- D. Melatonin
Correct answer: D
Rationale: Melatonin is the hormone produced by the pineal gland. It plays a crucial role in regulating the sleep-wake cycle and is instrumental in maintaining the body's circadian rhythm. Melatonin production is triggered by darkness and inhibited by light, aiding in signaling the body when it is time to sleep. Corticosteroid, oxytocin, and prolactin are hormones produced by other glands in the body and are not associated with the pineal gland. Therefore, they are incorrect choices for this question.
5. Which is a posterior feature of the human leg?
- A. Patella
- B. Quadriceps sartorius
- C. Triceps brachii
- D. Achilles tendon
Correct answer: D
Rationale: The correct answer is the Achilles tendon. The Achilles tendon is a strong tendon located at the back of the human leg, connecting the calf muscles to the heel bone. This positioning makes it a posterior feature, situated at the rear of the leg. The patella, also known as the kneecap, is positioned at the front of the leg, making it an anterior feature. The quadriceps sartorius are muscles located in the front of the thigh, not at the back of the leg. Additionally, the triceps brachii is a muscle found in the upper arm, not in the leg, making it an incorrect choice.
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