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. How do the muscular and skeletal systems collaborate to facilitate movement?
- A. Muscles attached to tendons contract to bend the skeleton at the joints.
- B. The hard bones of the skeleton protect the voluntary muscles of the limbs.
- C. The cardiac muscles produce calcium that is needed for sturdy bones.
- D. Smooth muscles on internal organs leach excess minerals from the bones.
Correct answer: A
Rationale: The muscular system and the skeletal system collaborate to facilitate movement. Muscles are connected to bones through tendons and contract to generate movement at the joints. When muscles contract, they exert force on the bones, resulting in actions like bending the arm or leg. This coordinated effort between muscles and bones is crucial for various activities such as walking, running, and grasping objects. Choices B, C, and D are incorrect because they do not accurately describe the interaction between the muscular and skeletal systems. The skeletal system's primary role is to provide structural support and protect internal organs, while cardiac muscles are responsible for heart function and not bone strength. Smooth muscles are found in internal organs and are not involved in leaching excess minerals from bones.
3. 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.
4. What is the function of platelets in the blood?
- A. Transporting oxygen
- B. Clotting blood
- C. Fighting infection
- D. Transporting nutrients
Correct answer: B
Rationale: Platelets, also known as thrombocytes, are responsible for clotting blood. When there is an injury, platelets help form blood clots to prevent excessive bleeding. This function is crucial in maintaining hemostasis and preventing hemorrhage. Choices A, C, and D are incorrect. Platelets do not transport oxygen, fight infection, or transport nutrients in the blood.
5. Which brain structure is involved in memory formation?
- A. Hippocampus
- B. Amygdala
- C. Cerebellum
- D. Medulla oblongata
Correct answer: A
Rationale: The hippocampus is the correct answer. It plays a crucial role in memory formation, particularly in the creation of new memories and their association with learning and emotions. Damage to the hippocampus can result in memory impairments, highlighting its significance in cognitive functions. The amygdala (Choice B) is involved in the processing of emotions, while the cerebellum (Choice C) is primarily associated with motor control and coordination. The medulla oblongata (Choice D) is responsible for vital autonomic functions like breathing and heart rate regulation, not memory formation.
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