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 part of the brain is responsible for regulating breathing and heart rate?
- A. Cerebrum
- B. Medulla oblongata
- C. Cerebellum
- D. Hypothalamus
Correct answer: B
Rationale: The correct answer is the Medulla oblongata. This structure, located in the brainstem, plays a crucial role in regulating essential functions such as breathing, heart rate, and blood pressure. It serves as a control center for autonomic functions necessary for maintaining life. The Cerebrum (Choice A) is mainly responsible for higher brain functions such as thinking and voluntary movements, not for regulating basic physiological processes like breathing and heart rate. The Cerebellum (Choice C) is involved in coordination, balance, and muscle control, but not in regulating breathing and heart rate. The Hypothalamus (Choice D) plays a role in regulating body temperature, hunger, and thirst, but it is not primarily responsible for controlling breathing and heart rate.
3. When an individual is under stress, hormones are released. Which of the following is not one of the locations in which hormones are released when under stress?
- A. Posterior pituitary
- B. Hypothalamus
- C. Adrenal cortex
- D. Parathyroid
Correct answer: D
Rationale: During stress, hormones are released from the adrenal cortex, posterior pituitary, and hypothalamus to help the body respond. The parathyroid gland, however, is not typically involved in the stress response by releasing hormones. The posterior pituitary releases hormones like oxytocin and vasopressin, the hypothalamus secretes corticotropin-releasing hormone (CRH) and vasopressin, while the adrenal cortex releases cortisol and aldosterone in response to stress. Therefore, the correct answer is 'Parathyroid.'
4. What is the main function of the adrenal glands?
- A. Regulation of metabolism
- B. Production of bile
- C. Regulation of blood pressure
- D. Production of insulin
Correct answer: C
Rationale: The main function of the adrenal glands is to produce hormones like adrenaline and cortisol. These hormones play a crucial role in regulating blood pressure, metabolism, and the body's stress response. While the adrenal glands do have some impact on metabolism, their primary function is not the direct regulation of metabolism. They are not involved in the production of bile or insulin. Therefore, the correct answer is the regulation of blood pressure.
5. Which of the following structures has the lowest blood pressure?
- A. arteries
- B. arterioles
- C. venules
- D. veins
Correct answer: D
Rationale: Veins have the lowest blood pressure among the listed structures. This is because veins carry blood back to the heart at a slower rate compared to arteries, arterioles, and venules. The lower blood pressure in veins allows for the efficient return of blood to the heart despite the decreased pressure. Arteries have high blood pressure as they transport blood away from the heart at a rapid rate. Arterioles are smaller branches of arteries and contribute to resistance in the circulatory system, leading to a pressure drop. Venules are small blood vessels that collect blood from capillaries and gradually converge into veins, having slightly higher pressure than veins.
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