HESI A2
HESI A2 Practice Test Anatomy and Physiology
1. Which of the following structures regulates the transport of substances in and out of a cell?
- A. Nucleus
- B. Cell membrane
- C. Cytoplasm
- D. Mitochondria
Correct answer: B
Rationale: The cell membrane, also known as the plasma membrane, is responsible for regulating the transport of substances in and out of the cell. It acts as a selective barrier, allowing the passage of certain molecules while restricting others. This selective permeability helps maintain homeostasis within the cell by controlling the movement of essential substances like nutrients and waste products. The nucleus (Choice A) is the organelle that houses the cell's genetic material and is not directly involved in regulating substance transport. Cytoplasm (Choice C) is the gel-like substance that fills the cell and does not play a direct role in regulating substance transport. Mitochondria (Choice D) are responsible for energy production in the cell through cellular respiration and are not primarily involved in substance transport.
2. Which of the following statements is anatomically correct?
- A. The knee is distal to the ankle.
- B. The heart is inferior to the diaphragm.
- C. The hip is proximal to the knee.
- D. The wrist is proximal to the elbow.
Correct answer: C
Rationale: The term 'proximal' refers to a body part being closer to the center of the body or a point of reference. In this case, the hip is closer to the center of the body compared to the knee, which makes the statement anatomically correct. Choice A is incorrect as the knee is proximal to the ankle. Choice B is incorrect as the heart is superior to the diaphragm. Choice D is incorrect as the elbow is proximal to the wrist.
3. What is the primary function of the kidneys in the urinary system?
- A. Regulating blood pressure
- B. Filtering blood to remove waste
- C. Producing red blood cells
- D. Regulating electrolyte balance
Correct answer: B
Rationale: The primary function of the kidneys in the urinary system is to filter blood to remove waste products and excess fluids, which are then excreted as urine. Kidneys act as a filtration system, removing waste like urea, excess salts, and toxins. While the kidneys do play a role in regulating blood pressure by secreting renin and maintaining electrolyte balance by adjusting the levels of sodium, potassium, and other ions in the blood, their main and essential function is filtration and waste removal, making choice B the correct answer.
4. What is a primary function of the skeletal system?
- A. Production of red blood cells
- B. Support and protection
- C. Secretion of hormones
- D. Regulation of body temperature
Correct answer: B
Rationale: The correct answer is B: Support and protection. The primary functions of the skeletal system include providing structural support to the body and protecting internal organs. While the skeletal system also plays a role in hematopoiesis (production of blood cells) and stores minerals, its main function is to support the body's framework and protect vital organs. Choices A, C, and D are incorrect as they do not directly relate to the primary functions of the skeletal system.
5. 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.
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