HESI A2
Quizlet HESI A2 Anatomy and Physiology
1. 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.
2. Which hormone is produced by the adrenal medulla?
- A. Insulin
- B. Adrenaline
- C. Cortisol
- D. Melatonin
Correct answer: B
Rationale: Adrenaline, also known as epinephrine, is the correct hormone produced by the adrenal medulla. It plays a crucial role in the body's fight-or-flight response, increasing heart rate, dilating airways, and mobilizing energy stores to prepare the body for perceived threats. Insulin (Choice A) is produced by the pancreas and regulates blood sugar levels, not by the adrenal medulla. Cortisol (Choice C) is produced by the adrenal cortex and is involved in regulating metabolism, immune response, and stress. Melatonin (Choice D) is produced by the pineal gland and regulates the sleep-wake cycle.
3. Which hormone is involved in the body's stress response?
- A. Insulin
- B. Adrenaline
- C. Cortisol
- D. Melatonin
Correct answer: C
Rationale: The correct answer is C: Cortisol. Cortisol, produced by the adrenal glands, is involved in the body's stress response. It helps regulate metabolism, immune function, and the body's response to stressors by increasing blood sugar levels, suppressing the immune system, and aiding in the metabolism of fats, carbohydrates, and proteins. Choice A, Insulin, is a hormone that regulates blood sugar levels and is not primarily involved in the stress response. Choice B, Adrenaline, is also known as epinephrine and is involved in the fight-or-flight response, which is related to stress but is not the main hormone in the body's stress response. Choice D, Melatonin, is a hormone that regulates sleep-wake cycles and is not directly involved in the stress response.
4. What is the main function of the lymphatic system?
- A. To transport oxygen
- B. To produce hormones
- C. To fight infections
- D. To transport nutrients
Correct answer: C
Rationale: The main function of the lymphatic system is to fight infections. It achieves this by filtering lymph, returning excess tissue fluid to the bloodstream, and aiding in the body's immune response. The lymphatic system is crucial in protecting the body against pathogens and maintaining overall health. Choices A, B, and D are incorrect because transporting oxygen, producing hormones, and transporting nutrients are functions performed by other systems in the body, like the respiratory, endocrine, and circulatory systems, respectively.
5. Which type of muscle is found in the walls of hollow organs?
- A. Skeletal muscle
- B. Cardiac muscle
- C. Smooth muscle
- D. Striated muscle
Correct answer: C
Rationale: Smooth muscle tissue is found in the walls of hollow organs, such as the intestines, blood vessels, and bladder. It contracts involuntarily, allowing for movements like peristalsis in the intestines and regulation of blood flow in blood vessels. Skeletal muscle (Choice A) is attached to bones and helps in voluntary movements. Cardiac muscle (Choice B) is found in the heart and contracts involuntarily to pump blood. Striated muscle (Choice D) refers to both skeletal and cardiac muscles, which have a striped appearance due to the organization of their filaments. However, smooth muscle (Choice C) is specifically the type found in hollow organs.
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