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 hormone is involved in the regulation of water balance in the body?
- A. ADH
- B. Insulin
- C. Cortisol
- D. Thyroxine
Correct answer: A
Rationale: The correct answer is ADH (antidiuretic hormone), also known as vasopressin. ADH helps regulate water balance in the body by controlling the amount of water reabsorbed by the kidneys. When there is a need to conserve water, ADH levels increase, leading to more water reabsorption and concentration of urine. Insulin is involved in regulating blood sugar levels, not water balance. Cortisol is a stress hormone that helps regulate metabolism and immune response, not water balance. Thyroxine is a thyroid hormone that regulates metabolism, growth, and development, not water balance.
3. Which organelle in the cell is responsible for packaging and distributing proteins?
- A. Ribosome
- B. Golgi apparatus
- C. Endoplasmic reticulum
- D. Mitochondrion
Correct answer: B
Rationale: The Golgi apparatus is an organelle responsible for packaging and distributing proteins and lipids within the cell. It modifies, sorts, and packages these molecules into vesicles for transportation to their final destinations, either within the cell or outside of it. The Golgi apparatus plays a crucial role in the secretory pathway of cells, ensuring that proteins are properly processed and directed to where they are needed. Ribosomes are responsible for protein synthesis, not packaging and distributing proteins. The endoplasmic reticulum is involved in protein synthesis and folding but not primarily in packaging and distributing proteins. Mitochondria are known as the powerhouse of the cell and are responsible for generating energy in the form of ATP through cellular respiration, not packaging and distributing proteins.
4. Which hormone regulates the sleep-wake cycle?
- A. Melatonin
- B. Insulin
- C. Cortisol
- D. Thyroxine
Correct answer: A
Rationale: Melatonin, produced by the pineal gland, is the hormone that regulates the sleep-wake cycle. Its secretion is influenced by light exposure, with levels typically rising in the evening to promote sleep and falling in the morning to encourage wakefulness. Insulin is involved in regulating blood sugar levels, not the sleep-wake cycle. Cortisol plays a role in the body's stress response and circadian rhythm but is not the primary hormone regulating sleep-wake cycles. Thyroxine is a hormone produced by the thyroid gland that regulates metabolism, not the sleep-wake cycle.
5. Which structure in the ear is responsible for hearing?
- A. Cochlea
- B. Semicircular canals
- C. Ossicles
- D. Eustachian tube
Correct answer: A
Rationale: The cochlea, located in the inner ear, is responsible for detecting sound waves and converting them into neural signals that are sent to the brain for processing. It plays a crucial role in the process of hearing by translating mechanical vibrations into electrical signals that the brain can interpret as sound. The semicircular canals (Choice B) are responsible for balance and detecting head movements, not hearing. The ossicles (Choice C) are three tiny bones in the middle ear that transmit sound vibrations from the eardrum to the cochlea. The Eustachian tube (Choice D) helps equalize pressure between the middle ear and the atmosphere, but it is not directly involved in the process of hearing.
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