HESI A2 Anatomy and Physiology 2023

Correct Answer: C

Rationale: The correct answer is C: Occipital lobe. The occipital lobe is responsible for processing visual information as it contains the primary visual cortex. This part of the brain interprets visual stimuli received from the eyes. Other choices are incorrect because: A: Frontal lobe is primarily involved in higher-level thinking, decision-making, and motor functions. B: Parietal lobe processes sensory information, spatial awareness, and perception of stimuli like touch and pressure. D: Temporal lobe plays a role in auditory processing, memory, and language comprehension.

Correct Answer: B

Rationale: During the fight-or-flight response, the body needs to prepare for immediate action. Adrenaline, also known as epinephrine, is the hormone released by the adrenal glands in response to stress or danger. Adrenaline triggers physiological changes such as increased heart rate, blood flow to muscles, and heightened awareness to help the body react quickly. Insulin is involved in regulating blood sugar levels, not the fight-or-flight response. Thyroxine plays a role in metabolism, while cortisol is released in response to stress but is not the primary hormone involved in the fight-or-flight response.

Correct Answer: B

Rationale: The correct answer is B: Thyroxine. Thyroxine, produced by the thyroid gland, plays a key role in regulating metabolism by controlling the body's metabolic rate. It influences how fast or slow our cells use energy. Insulin (A) regulates blood sugar levels, not metabolism. Glucagon (C) raises blood sugar levels. Cortisol (D) is a stress hormone that affects various body functions but is not primarily responsible for regulating metabolism. Thyroxine is crucial for maintaining overall metabolic balance in the body.

Correct Answer: C

Rationale: The correct answer is C: Medulla oblongata. The medulla oblongata is located in the brainstem and is responsible for regulating essential functions such as heart rate and breathing. It contains vital centers that control autonomic functions, including the cardiovascular and respiratory systems. The medulla receives inputs from various sensory receptors and sends signals to the heart and lungs to maintain homeostasis. The other choices are incorrect because: A: Cerebrum is primarily responsible for higher brain functions such as thinking and voluntary movements. B: Cerebellum is involved in coordination and balance, not in regulating heart rate and breathing. D: Hypothalamus plays a role in regulating body temperature, hunger, and thirst, but not specifically in controlling heart rate and breathing.

Correct Answer: B

Rationale: The correct answer is B: Pinna. The pinna, also known as the auricle, is the most visible part of the ear located on the outside of the head. It helps collect sound waves and directs them into the ear canal. The other choices are incorrect because: A: Cochlea is a spiral-shaped organ in the inner ear responsible for hearing. C: Ear canal is the tube that connects the outer ear to the eardrum. D: Organ of Corti is a structure in the cochlea that contains sensory cells responsible for hearing.