HESI A2
HESI A2 Anatomy and Physiology 2023
1. Which hormone is secreted by the pancreas to lower blood glucose levels?
- A. Insulin
- B. Glucagon
- C. Somatostatin
- D. Cortisol
Correct answer: A
Rationale: Insulin is secreted by the pancreas to lower blood glucose levels by facilitating the uptake of glucose into cells. It promotes the storage of glucose as glycogen in the liver and muscles, reducing blood sugar levels. Glucagon, on the other hand, works to raise blood glucose levels by stimulating the breakdown of glycogen into glucose and releasing it into the bloodstream. Somatostatin regulates the endocrine system and inhibits the release of insulin and glucagon. Cortisol is a hormone produced by the adrenal glands, not the pancreas, and it plays a role in stress response and metabolism, but it does not directly lower blood glucose levels.
2. 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.
3. Which part of the brain controls breathing and heart rate?
- A. Cerebrum
- B. Medulla oblongata
- C. Cerebellum
- D. Hypothalamus
Correct answer: B
Rationale: The medulla oblongata, located in the brainstem, plays a crucial role in controlling vital functions such as breathing, heart rate, and blood pressure. It serves as the control center for automatic functions necessary for survival, making it the correct choice in this scenario. The cerebrum is responsible for higher brain functions like thinking and voluntary movements, so it does not control basic physiological functions like breathing and heart rate. The cerebellum is mainly involved in coordination and balance, while the hypothalamus regulates body temperature, hunger, and thirst, but not specifically breathing and heart rate.
4. Which structure in the eye is responsible for focusing light on the retina?
- A. Cornea
- B. Lens
- C. Retina
- D. Pupil
Correct answer: B
Rationale: The lens of the eye is responsible for focusing light onto the retina. It plays a crucial role in bending light rays to ensure that they converge on the retina, enabling clear vision. The cornea helps in focusing light, but the final adjustment and fine-tuning occur through the lens. The retina receives the focused light and converts it into neural signals for the brain to interpret. The pupil, on the other hand, controls the amount of light entering the eye by dilating or constricting.
5. Which part of the brain is responsible for balance and coordination?
- A. Cerebellum
- B. Cerebrum
- C. Medulla oblongata
- D. Hypothalamus
Correct answer: A
Rationale: The correct answer is the cerebellum. The cerebellum, situated at the back of the brain, is responsible for coordinating voluntary movements and maintaining balance and posture. It receives information from the sensory systems, the spinal cord, and other parts of the brain to regulate motor movements. The cerebrum (choice B) is responsible for higher brain functions such as thinking and decision-making, the medulla oblongata (choice C) controls vital autonomic functions like breathing and heart rate, and the hypothalamus (choice D) is involved in regulating basic biological needs like hunger, thirst, and body temperature.
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