HESI A2
HESI A2 Anatomy and Physiology Quizlet
1. Which part of the brain controls involuntary actions such as breathing and heart rate?
- A. Cerebrum
- B. Cerebellum
- C. Medulla oblongata
- D. Hypothalamus
Correct answer: C
Rationale: The medulla oblongata, located at the base of the brainstem, controls essential involuntary actions such as breathing, heart rate, and blood pressure. It plays a crucial role in maintaining vital functions necessary for survival. The cerebrum is responsible for voluntary actions, conscious thought, and sensory processing, making it an incorrect choice. The cerebellum primarily coordinates movement, balance, and posture, not involuntary actions like breathing and heart rate. The hypothalamus regulates body temperature, thirst, hunger, and controls the endocrine system, but it is not directly responsible for controlling breathing and heart rate.
2. Which neurotransmitter controls sleep, mood, and appetite?
- A. Serotonin
- B. Oxytocin
- C. Cortisol
- D. Aldosterone
Correct answer: A
Rationale: Serotonin is the correct answer. It is a neurotransmitter that plays a crucial role in regulating mood, sleep, and appetite. Serotonin functions to stabilize and control these physiological processes in the brain and body. Imbalances in serotonin levels are commonly linked to conditions like depression, anxiety, and eating disorders. Oxytocin (Choice B) is more associated with social bonding and childbirth. Cortisol (Choice C) is a stress hormone, and while it can influence mood and appetite in response to stress, it is not primarily responsible for regulating these functions. Aldosterone (Choice D) is a hormone that regulates electrolyte balance and blood pressure, not mood, sleep, and appetite.
3. 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.
4. 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.
5. What is the primary function of the alveoli in the lungs?
- A. Removing carbon dioxide from the blood
- B. Exchanging oxygen and carbon dioxide
- C. Transporting oxygen to the bloodstream
- D. Filtering blood
Correct answer: B
Rationale: The primary function of the alveoli in the lungs is to exchange oxygen and carbon dioxide. The alveoli are tiny air sacs in the lungs responsible for this gas exchange during breathing. Oxygen diffuses from the inhaled air into the blood in the capillaries surrounding the alveoli, while carbon dioxide diffuses from the blood into the alveoli to be exhaled out of the body. Choice A is incorrect because the alveoli primarily facilitate the exchange of gases, not just the removal of carbon dioxide. Choice C is incorrect as the alveoli do not transport oxygen to the bloodstream but rather facilitate the exchange of gases. Choice D is incorrect as the alveoli are not involved in filtering blood but in gas exchange to ensure proper oxygenation and removal of carbon dioxide in the respiratory process.
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