HESI A2
Anatomy HESI A2
1. The epidermis is classified as which of the following?
- A. Cell
- B. Tissue
- C. Organ
- D. System
Correct answer: B
Rationale: The epidermis is classified as a tissue, more specifically as a layer of cells that form the outermost part of the skin. It is composed of multiple layers of cells that protect underlying tissues and regulate various functions related to the skin. Choice A, Cell, is incorrect because the epidermis is not just a single cell but rather a collection of cells. Choice C, Organ, is incorrect because the epidermis is not an organ on its own but rather a part of an organ, the skin. Choice D, System, is incorrect because the epidermis is not a system but rather a component of the integumentary system.
2. Which type of muscle tissue is under voluntary control?
- A. Smooth muscle
- B. Cardiac muscle
- C. Skeletal muscle
- D. Cardiac muscle
Correct answer: C
Rationale: Skeletal muscle is under voluntary control, allowing conscious regulation for activities like walking and lifting. This type of muscle is attached to bones and is responsible for movement in the body. Smooth muscle (Choice A) is involuntary and found in organs like the stomach and intestines. Cardiac muscle (Choice B and D) is also involuntary and specific to the heart, contracting rhythmically to pump blood, but it is not under conscious control.
3. Which gland produces melatonin?
- A. Pineal gland
- B. Thyroid gland
- C. Adrenal gland
- D. Pituitary gland
Correct answer: A
Rationale: The correct answer is the Pineal gland. This gland is responsible for producing melatonin, a hormone that helps regulate the sleep-wake cycle. Melatonin production is influenced by exposure to light, with levels typically rising in the evening to promote sleep and falling in the morning to aid wakefulness. The Thyroid gland (choice B) produces hormones that regulate metabolism, the Adrenal gland (choice C) produces hormones like adrenaline and cortisol, and the Pituitary gland (choice D) controls several other glands in the endocrine system.
4. Nerve tissue is composed of neurons and connective tissue cells that are referred to as which of the following?
- A. Osteoblasts
- B. Neuroglia
- C. Osteocytes
- D. Arterioles
Correct answer: B
Rationale: Neuroglia are specialized connective tissue cells that provide support and protection to neurons in the nervous system. They assist in the proper functioning of neurons and are essential for maintaining the overall health of nerve tissue. Therefore, in the context of nerve tissue composition, neuroglia are the connective tissue cells associated with neurons. The other choices, osteoblasts, osteocytes, and arterioles, are not the correct types of connective tissue cells found in nerve tissue. Osteoblasts are involved in bone formation, osteocytes are mature bone cells, and arterioles are small blood vessels that supply blood to tissues.
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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