HESI A2
Quizlet HESI A2 Anatomy and Physiology
1. Which structure in the kidney is responsible for filtering blood?
- A. Glomerulus
- B. Bowman's capsule
- C. Loop of Henle
- D. Collecting duct
Correct answer: A
Rationale: The glomerulus is the correct answer. It is a vital structure in the kidney responsible for filtering blood. The glomerulus is a network of capillaries that filters waste products and excess substances from the blood to form urine. While the Bowman's capsule, Loop of Henle, and Collecting duct are also essential components of the nephron, the primary site of blood filtration occurs at the glomerulus. The Bowman's capsule surrounds the glomerulus and collects the filtered fluid, the Loop of Henle reabsorbs water and important ions, and the Collecting duct further concentrates the urine, but none of these structures are primarily responsible for filtering blood as the glomerulus is.
2. Which part of the brain is responsible for regulating involuntary functions such as breathing and heart rate?
- A. Cerebrum
- B. Cerebellum
- C. Medulla oblongata
- D. Frontal lobe
Correct answer: C
Rationale: The medulla oblongata, located in the brain stem, is responsible for regulating involuntary functions such as breathing and heart rate. It contains vital centers that control these essential functions to maintain life. The cerebrum is primarily involved in higher brain functions like thinking and voluntary movements; the cerebellum plays a crucial role in coordinating movement and balance; and the frontal lobe is responsible for functions such as decision-making, problem-solving, and voluntary muscle movements. Therefore, the correct answer is the medulla oblongata (Choice C).
3. Which hormone is involved in the fight or flight response?
- A. Cortisol
- B. Adrenaline
- C. Thyroxine
- D. Melatonin
Correct answer: B
Rationale: The correct answer is B: Adrenaline. Adrenaline, also known as epinephrine, is the hormone involved in the fight or flight response. It is released by the adrenal glands, preparing the body for action by increasing heart rate, dilating airways, and mobilizing energy stores. Choice A, Cortisol, is a hormone released in response to stress but is not directly involved in the fight or flight response. Choice C, Thyroxine, is a hormone produced by the thyroid gland that regulates metabolism and growth, not specifically associated with the fight or flight response. Choice D, Melatonin, is a hormone that regulates sleep-wake cycles and is not involved in the fight or flight response.
4. The motor cortex is essential for monitoring and controlling body movements. Where is the motor cortex located within the brain?
- A. Top, middle portion of the parietal lobe
- B. Back of the head
- C. Front portion of the parietal lobe
- D. Around the auditory cortex
Correct answer: C
Rationale: The motor cortex is located in the frontal portion of the brain, specifically in the precentral gyrus of the frontal lobe. It plays a crucial role in planning, controlling, and executing voluntary movements. Choice A, 'Top, middle portion of the parietal lobe,' is incorrect because the motor cortex is not located in the parietal lobe but rather in the frontal lobe. Choice B, 'Back of the head,' is incorrect as it refers to the occipital lobe, not where the motor cortex is situated. Choice D, 'Around the auditory cortex,' is incorrect as the motor cortex is not located around the auditory cortex but in the frontal lobe, as mentioned earlier.
5. 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.
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