HESI A2 Anatomy and Physiology 2023

Correct Answer: C

Rationale: The correct answer is C: Front portion of the parietal lobe. This area is known as the primary motor cortex, responsible for planning, control, and execution of voluntary movements. It receives input from other brain regions involved in movement. Choices A, B, and D are incorrect because the top, middle portion of the parietal lobe is involved in sensory processing, the back of the head is associated with the occipital lobe responsible for vision, and around the auditory cortex is involved in processing auditory information, respectively.

Correct Answer: B

Rationale: The correct answer is B: Skin. The skin is the largest organ in the human body by surface area, covering about 20 square feet on average. It serves as a protective barrier against external elements and plays a crucial role in regulating body temperature. The liver (A), brain (C), and heart (D) are important organs, but they are not the largest in terms of size or surface area. Therefore, the correct choice is the skin.

Correct Answer: A

Rationale: The correct answer is A: Cerebellum. The cerebellum is responsible for balance and coordination as it receives sensory information from the inner ear and muscles to control movement. It coordinates muscle actions and maintains posture. The cerebrum (B) is responsible for higher brain functions, the medulla oblongata (C) controls basic life functions like breathing and heart rate, and the hypothalamus (D) regulates body temperature, hunger, and thirst. Thus, the cerebellum is the most appropriate choice for balance and coordination.

Correct Answer: B

Rationale: The correct answer is B: Support and protection. The skeletal system provides structural support for the body and protects internal organs. It also helps with movement, stores minerals, and produces blood cells. Choices A, C, and D are incorrect because the production of red blood cells occurs in the bone marrow, secretion of hormones is primarily the function of the endocrine system, and regulation of body temperature is controlled by the nervous system and other mechanisms, not the skeletal system.

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.