HESI A2
HESI A2 Anatomy and Physiology 2023
1. Which gland is known as the 'master gland' of the body?
- A. Thyroid gland
- B. Adrenal gland
- C. Pituitary gland
- D. Pineal gland
Correct answer: C
Rationale: The pituitary gland, often referred to as the 'master gland,' controls the release of hormones from other endocrine glands in the body. It secretes various hormones that regulate many bodily functions, making it a central and vital component of the endocrine system. The thyroid gland (Choice A) regulates metabolism, the adrenal gland (Choice B) produces hormones like adrenaline, and the pineal gland (Choice D) secretes melatonin, but none of these glands are considered the 'master gland' that controls the functions of other endocrine glands.
2. Which type of muscle is under voluntary control?
- A. Smooth muscle
- B. Cardiac muscle
- C. Skeletal muscle
- D. Striated muscle
Correct answer: C
Rationale: The correct answer is C: Skeletal muscle. Skeletal muscle is under voluntary control, allowing individuals to consciously regulate its contractions for movement. Examples of skeletal muscle control include actions like walking, running, and lifting weights. Smooth muscle (choice A) and cardiac muscle (choice B) are both involuntary muscles, meaning they are not under conscious control. While skeletal muscle is striated (choice D), striated muscle is a broader category that includes both voluntary (skeletal) and involuntary (cardiac) muscles.
3. 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).
4. 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.
5. What is the primary function of white blood cells?
- A. To carry oxygen
- B. To fight infections
- C. To transport nutrients
- D. To clot blood
Correct answer: B
Rationale: White blood cells, also known as leukocytes, play a crucial role in the immune system by primarily fighting off infections caused by pathogens like bacteria, viruses, and other invaders. They help the body recognize and destroy these harmful agents, contributing to the body's defense mechanisms against diseases. Choice A is incorrect because the primary function of red blood cells, not white blood cells, is to carry oxygen. Choice C is incorrect as the transportation of nutrients is mainly carried out by the bloodstream as a whole, not specifically by white blood cells. Choice D is incorrect as the process of blood clotting is primarily managed by platelets in the blood, not white blood cells.
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