HESI A2
Anatomy HESI A2
1. 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.
2. Which type of muscle is found in the heart?
- A. Smooth muscle
- B. Cardiac muscle
- C. Skeletal muscle
- D. Striated muscle
Correct answer: B
Rationale: Cardiac muscle is a specialized type of muscle found only in the heart. It is responsible for the rhythmic contractions that pump blood throughout the body. Unlike smooth and skeletal muscle, cardiac muscle has its own unique structure and function to meet the demands of the heart's continuous pumping action. Smooth muscle is found in the walls of internal organs and blood vessels, not in the heart. Skeletal muscle is attached to bones and helps in movement but is not found in the heart. Striated muscle is a broader term that includes both cardiac and skeletal muscle, but specifically, cardiac muscle refers to the muscle tissue of the heart.
3. Which type of joint is found in the neck and allows for rotational movement?
- A. Hinge joint
- B. Pivot joint
- C. Ball and socket joint
- D. Saddle joint
Correct answer: B
Rationale: The correct answer is B: Pivot joint. A pivot joint, like the one found in the neck, allows for rotational movement, enabling the head to turn from side to side. Hinge joints (Choice A) allow movement in one plane like a door hinge and are not found in the neck. Ball and socket joints (Choice C) allow for a wide range of motion in multiple directions and are typically found in the hip and shoulder. Saddle joints (Choice D) allow for movement back and forth and side to side, like the thumb joint, but are not found in the neck.
4. Which part of the brain controls balance and coordination?
- A. Cerebellum
- B. Cerebrum
- C. Medulla oblongata
- D. Brainstem
Correct answer: A
Rationale: The correct answer is the cerebellum. Located at the back of the brain, the cerebellum plays a crucial role in controlling balance, coordination, and fine motor movements. It receives information from the sensory systems, the spinal cord, and other parts of the brain to coordinate voluntary movements and maintain posture. Damage to the cerebellum can result in issues with balance, coordination, and muscle tone. The cerebrum is responsible for higher brain functions like thinking and problem-solving, the medulla oblongata controls vital autonomic functions like breathing and heartbeat, and the brainstem serves as a pathway for neural fibers traveling to and from the brain.
5. What is the primary function of platelets?
- A. To fight infections
- B. To clot blood
- C. To carry oxygen
- D. To transport nutrients
Correct answer: B
Rationale: The primary function of platelets, or thrombocytes, is to clot blood. Platelets play a crucial role in hemostasis by forming clots to prevent excessive bleeding when injuries occur. They are not directly involved in fighting infections, carrying oxygen, or transporting nutrients. Therefore, the correct answer is B.
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