HESI A2
HESI A2 Anatomy and Physiology Practice Test 2023
1. What is the primary function of the immune system?
- A. To transport oxygen
- B. To fight infections
- C. To produce energy
- D. To regulate body temperature
Correct answer: B
Rationale: The primary function of the immune system is to fight infections. It identifies and destroys pathogens like bacteria and viruses, protecting the body from harmful substances. While oxygen transportation is carried out by the respiratory system, energy production is mainly the role of the metabolic system, and body temperature regulation is managed by the thermoregulatory system. These functions are separate from the immune system's primary role of defending the body against infections.
2. What is the most visible part of the ear?
- A. Pinna
- B. Organ of Corti
- C. Cochlea
- D. Ear canal
Correct answer: A
Rationale: The pinna, also known as the auricle, is the external part of the ear that is most visible. It helps in collecting sound waves and directing them into the ear canal for further processing by the ear structures. The pinna's visible location makes it easily identifiable as the prominent external feature of the ear. Choices B, C, and D are incorrect. The Organ of Corti is located within the cochlea and is responsible for converting sound vibrations into electrical signals. The cochlea is a spiral-shaped, fluid-filled structure in the inner ear that plays a crucial role in hearing. The ear canal is a passage that leads to the eardrum and is not the most visible part of the ear.
3. Which hormone is produced by the pineal gland?
- A. Corticosteroid
- B. Oxytocin
- C. Prolactin
- D. Melatonin
Correct answer: D
Rationale: Melatonin is the hormone produced by the pineal gland. It plays a crucial role in regulating the sleep-wake cycle and is instrumental in maintaining the body's circadian rhythm. Melatonin production is triggered by darkness and inhibited by light, aiding in signaling the body when it is time to sleep. Corticosteroid, oxytocin, and prolactin are hormones produced by other glands in the body and are not associated with the pineal gland. Therefore, they are incorrect choices for this question.
4. How does the lymphatic system work with the circulatory system?
- A. The circulatory system produces red blood cells for the lymphatic system.
- B. Lymph draws excess fluid from the cells and deposits it into the blood vessels.
- C. The heart regulates the production of lymph in the lymph glands.
- D. White cells from the lymphatic system eliminate excess red blood cells.
Correct answer: B
Rationale: The lymphatic system works with the circulatory system by draining excess fluid and waste products from the spaces between cells, known as interstitial fluid. This excess fluid, now called lymph, is then transported back into the blood circulation through lymphatic vessels. This process helps maintain fluid balance in the body and supports the circulatory system in regulating blood volume and pressure. Choice A is incorrect because the circulatory system does not produce red blood cells for the lymphatic system. Choice C is incorrect as the heart does not regulate lymph production in lymph glands. Choice D is incorrect as white cells from the lymphatic system do not eliminate excess red blood cells. Therefore, the correct answer is B, as lymph draws excess fluid from the cells and deposits it into the blood vessels, aiding in maintaining proper fluid balance and supporting the circulatory system.
5. Which hormone is responsible for regulating the sleep-wake cycle?
- A. Melatonin
- B. Thyroxine
- C. Insulin
- D. Cortisol
Correct answer: A
Rationale: Melatonin, produced by the pineal gland, regulates the sleep-wake cycle by responding to light and darkness in the environment. It plays a crucial role in signaling the body when it's time to sleep and wake up, helping to establish and maintain a healthy circadian rhythm. Thyroxine, Insulin, and Cortisol do not directly regulate the sleep-wake cycle, making them incorrect choices for this question.
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