HESI A2
HESI A2 Anatomy and Physiology Practice Test
1. What are the chemical messengers that control growth, differentiation, and metabolism of specific target cells called?
- A. Hormones
- B. Neurons
- C. Glands
- D. Second messengers
Correct answer: A
Rationale: Hormones are signaling molecules produced by glands in multicellular organisms. They travel through the bloodstream to specific target cells where they regulate various physiological processes, including growth, differentiation, and metabolism. Neurons (choice B) are nerve cells that transmit nerve impulses and are not responsible for controlling growth, differentiation, or metabolism. Glands (choice C) produce and release hormones but are not the chemical messengers themselves. Second messengers (choice D) are molecules involved in intracellular signal transduction, not the primary chemical messengers controlling growth, differentiation, and metabolism. Therefore, hormones (choice A) are the correct answer as they match the description provided in the question.
2. Which organ system is primarily responsible for storing minerals?
- A. The skeletal system
- B. The endocrine system
- C. The lymphatic system
- D. The cardiovascular system
Correct answer: A
Rationale: The skeletal system is primarily responsible for storing minerals in the body. Bones serve as a storage site for essential minerals such as calcium and phosphorus, which are important for various bodily functions including bone strength, muscle contraction, and nerve signaling. The minerals stored in bones can be released into the bloodstream as needed to maintain optimal mineral levels in the body. The endocrine system is responsible for hormone regulation, not mineral storage. The lymphatic system is involved in immune function and fluid balance, not mineral storage. The cardiovascular system is responsible for circulating blood throughout the body, not storing minerals.
3. Which part of the brain is responsible for memory and learning?
- A. Frontal lobe
- B. Temporal lobe
- C. Parietal lobe
- D. Occipital lobe
Correct answer: B
Rationale: The correct answer is B: Temporal lobe. The temporal lobe of the brain plays a crucial role in processing auditory information, memory formation, and learning. It contains the hippocampus, a structure vital for the formation of new memories and the conversion of short-term memories into long-term ones. Damage to the temporal lobe can lead to memory impairments and difficulties in learning new information. Choices A, C, and D are incorrect because the frontal lobe is primarily involved in decision making, problem-solving, and emotional control; the parietal lobe is responsible for sensory processing and spatial orientation; and the occipital lobe is mainly dedicated to visual processing and interpretation.
4. What is the function of parathyroid hormone?
- A. Increasing energy levels
- B. Stimulating cell reproduction
- C. Speeding up metabolism
- D. Activating vitamin D
Correct answer: D
Rationale: The correct answer is D. Parathyroid hormone plays a crucial role in activating vitamin D. This activation occurs in the kidneys, where parathyroid hormone stimulates the conversion of inactive vitamin D to its active form. Active vitamin D is essential for maintaining proper levels of calcium and phosphorus in the body, which are important for bone health and other physiological functions. Choices A, B, and C are incorrect because parathyroid hormone is not involved in increasing energy levels, stimulating cell reproduction, or speeding up metabolism. Its primary function is related to calcium and phosphorus homeostasis through the activation of vitamin D.
5. What is the main component of the cell membrane?
- A. Proteins
- B. Carbohydrates
- C. Lipids
- D. Nucleic acids
Correct answer: C
Rationale: The main component of the cell membrane is the phospholipid bilayer, which is primarily composed of lipids. Lipids form a barrier that separates the interior of the cell from the external environment, providing structural integrity and regulating the passage of substances in and out of the cell. Proteins are also essential components of the cell membrane, serving various functions such as transport, signaling, and cell recognition. Carbohydrates are present in the form of glycoproteins and glycolipids on the cell membrane surface, contributing to cell-cell recognition. Nucleic acids are not a primary component of the cell membrane.
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