HESI A2
Anatomy HESI A2
1. Which hormone stimulates milk production in the breasts during lactation?
- A. norepinephrine
- B. antidiuretic hormone
- C. prolactin
- D. oxytocin
Correct answer: C
Rationale: During lactation, the hormone responsible for stimulating milk production in the breasts is 'prolactin.' Prolactin plays a crucial role in initiating and maintaining lactation by promoting the development of alveoli in the mammary glands and stimulating milk synthesis. While oxytocin is involved in the ejection of milk from the breasts, it is prolactin that primarily governs milk production. Norepinephrine is not directly involved in milk production, and antidiuretic hormone primarily regulates water balance and blood pressure, not milk production.
2. Which gland produces the hormone melatonin?
- A. Pineal gland
- B. Thyroid gland
- C. Pituitary gland
- D. Adrenal gland
Correct answer: A
Rationale: The correct answer is the Pineal gland. The pineal gland is responsible for producing melatonin, a hormone that helps regulate the sleep-wake cycle. Melatonin secretion is influenced by light exposure. Higher levels are observed at night to promote sleep, while lower levels during the day encourage wakefulness. Choices B, C, and D are incorrect as they are not associated with the production of melatonin. The thyroid gland produces hormones like thyroxine and triiodothyronine, the pituitary gland controls various other glands, and the adrenal gland produces hormones like adrenaline and cortisol.
3. Which part of the brain is responsible for balance and coordination?
- A. Cerebellum
- B. Cerebrum
- C. Medulla oblongata
- D. Hypothalamus
Correct answer: A
Rationale: The correct answer is the cerebellum. The cerebellum, situated at the back of the brain, is responsible for coordinating voluntary movements and maintaining balance and posture. It receives information from the sensory systems, the spinal cord, and other parts of the brain to regulate motor movements. The cerebrum (choice B) is responsible for higher brain functions such as thinking and decision-making, the medulla oblongata (choice C) controls vital autonomic functions like breathing and heart rate, and the hypothalamus (choice D) is involved in regulating basic biological needs like hunger, thirst, and body temperature.
4. Which parts of the heart are separated by the mitral valve?
- A. Left atrium and right atrium
- B. Right atrium and right ventricle
- C. Left ventricle and right ventricle
- D. Left atrium and left ventricle
Correct answer: D
Rationale: The mitral valve, also known as the bicuspid valve, separates the left atrium and the left ventricle of the heart. Its primary function is to prevent the backflow of blood from the left ventricle to the left atrium during the heart's contraction. Therefore, option D, 'Left atrium and left ventricle,' is the correct answer. Choices A, B, and C are incorrect because they do not represent the parts separated by the mitral valve.
5. 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.
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