HESI A2
Anatomy HESI A2
1. Which part of the brain is responsible for regulating involuntary functions such as breathing and heart rate?
- A. Cerebrum
- B. Cerebellum
- C. Medulla oblongata
- D. Frontal lobe
Correct answer: C
Rationale: The medulla oblongata, located in the brain stem, is responsible for regulating involuntary functions such as breathing and heart rate. It contains vital centers that control these essential functions to maintain life. The cerebrum is primarily involved in higher brain functions like thinking and voluntary movements; the cerebellum plays a crucial role in coordinating movement and balance; and the frontal lobe is responsible for functions such as decision-making, problem-solving, and voluntary muscle movements. Therefore, the correct answer is the medulla oblongata (Choice C).
2. What is the meaning of exocytosis?
- A. The cell engulfs and brings in substances.
- B. The cell releases content outside by fusing with the plasma membrane.
- C. The cell engulfs liquid material.
- D. The cell brings in solid particles.
Correct answer: B
Rationale: Exocytosis is the process by which a cell releases substances to the outside by fusing with the plasma membrane. During exocytosis, vesicles containing molecules fuse with the cell membrane, allowing the release of the contents outside the cell. This process is crucial for the secretion of various substances such as hormones, enzymes, and neurotransmitters. Choices A, C, and D are incorrect as they describe processes different from exocytosis. Choice A describes endocytosis, where the cell engulfs substances to bring them into the cell. Choice C is more aligned with pinocytosis, the process of engulfing liquid material. Choice D refers to phagocytosis, which is the uptake of solid particles by the cell.
3. What condition might result from a lack of vitamin C?
- A. Kwashiorkor
- B. Pellagra
- C. Rickets
- D. Scurvy
Correct answer: D
Rationale: Scurvy is the correct answer. Scurvy is a condition caused by a deficiency of vitamin C in the diet. Vitamin C is essential for collagen synthesis, and its deficiency leads to symptoms such as weakness, swollen and bleeding gums, joint pain, fatigue, and easy bruising. If left untreated, scurvy can lead to more severe complications. Choices A, B, and C are incorrect. Kwashiorkor is a severe form of malnutrition due to insufficient protein intake, pellagra is caused by a deficiency of niacin (vitamin B3), and rickets results from a deficiency of vitamin D, calcium, or phosphate.
4. Which cellular structure is responsible for protein synthesis?
- A. Nucleus
- B. Ribosome
- C. Endoplasmic reticulum
- D. Golgi apparatus
Correct answer: B
Rationale: The correct answer is B: Ribosome. Ribosomes, the cellular structures located in the cytoplasm or on the endoplasmic reticulum, are responsible for protein synthesis in the cell. They are the sites where mRNA is translated into proteins, making them essential for the synthesis of proteins in all living cells. The other choices, such as the nucleus (choice A), endoplasmic reticulum (choice C), and Golgi apparatus (choice D), are not directly involved in protein synthesis. The nucleus contains DNA and is responsible for housing the genetic material, the endoplasmic reticulum is involved in protein folding and transport, and the Golgi apparatus is responsible for modifying, sorting, and packaging proteins.
5. Which hormone stimulates the production of red blood cells?
- A. Insulin
- B. Erythropoietin
- C. Glucagon
- D. Thyroxine
Correct answer: B
Rationale: Erythropoietin is the correct answer. It is the hormone responsible for stimulating the production of red blood cells. Erythropoietin is produced by the kidneys in response to low oxygen levels in the blood. This hormone promotes the generation of more red blood cells to increase the blood's oxygen-carrying capacity. Insulin (Choice A), Glucagon (Choice C), and Thyroxine (Choice D) do not stimulate the production of red blood cells. Insulin regulates blood sugar levels, Glucagon increases blood sugar levels, and Thyroxine regulates metabolism.
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