HESI A2
HESI A2 Anatomy and Physiology Quizlet
1. Which structure in the brain regulates sleep and wakefulness?
- A. Hypothalamus
- B. Thalamus
- C. Pineal gland
- D. Cerebellum
Correct answer: C
Rationale: The pineal gland, located in the brain, is responsible for regulating sleep and wakefulness by secreting the hormone melatonin. Melatonin plays a crucial role in controlling the sleep-wake cycle, with higher levels at night inducing sleepiness. The hypothalamus (Choice A) regulates various physiological processes but is not primarily responsible for sleep-wake cycles. The thalamus (Choice B) is involved in relaying sensory information but not specifically in regulating sleep. The cerebellum (Choice D) plays a role in coordination and motor control rather than sleep regulation.
2. Which of the following is not an example of a nonspecific immune response?
- A. Inflammation
- B. Vasodilation
- C. Release of histamine
- D. Production of antibodies
Correct answer: D
Rationale: The correct answer is D, 'Production of antibodies.' Antibodies are generated as part of the specific immune response, which targets specific antigens. Nonspecific immune responses, such as inflammation, vasodilation, and histamine release, are general defense mechanisms aimed at combating various pathogens. Inflammation is a localized response to infection or injury, vasodilation increases blood flow to the affected area, and histamine release triggers inflammatory responses. It's vital to differentiate between nonspecific responses that provide immediate, general protection and specific responses designed to tackle particular threats.
3. What is the function of hemoglobin in red blood cells?
- A. To fight infections
- B. To transport oxygen
- C. To carry carbon dioxide
- D. To store oxygen
Correct answer: B
Rationale: The correct answer is B: 'To transport oxygen.' Hemoglobin in red blood cells plays a crucial role in transporting oxygen. It binds to oxygen in the lungs and carries it to the body's tissues and organs for cellular respiration. Choices A, C, and D are incorrect because hemoglobin's primary function is to bind and transport oxygen, not to fight infections, carry carbon dioxide, or store oxygen.
4. Which hormone regulates blood sugar levels?
- A. Insulin
- B. Glucagon
- C. Cortisol
- D. Thyroxine
Correct answer: A
Rationale: Insulin is the hormone that regulates blood sugar levels by promoting the uptake of glucose into cells. It is produced by the pancreas and helps to lower blood sugar levels when they are too high. Glucagon, on the other hand, works in opposition to insulin by raising blood sugar levels when they are too low. Cortisol and thyroxine play different roles in the body and are not primarily responsible for regulating blood sugar levels.
5. Which of the following is not part of the central nervous system?
- A. Retina
- B. Spinal cord
- C. Brain
- D. Heart
Correct answer: B
Rationale: The central nervous system consists of the brain and spinal cord, which are responsible for processing and coordinating information. The retina is part of the eye, while the heart is part of the circulatory system. Therefore, the correct answer is 'Spinal cord' as it is not part of the central nervous system.
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