HESI A2 Anatomy and Physiology 2023

Correct Answer: B

Rationale: The correct answer is B: Skeletal muscle. Skeletal muscle is voluntary as it is under conscious control, allowing us to move our body voluntarily. Cardiac muscle (A) is involuntary and found in the heart. Smooth muscle (C) is also involuntary and found in internal organs. Striated muscle (D) is a general term that can refer to both skeletal and cardiac muscle, but not all striated muscles are voluntary. Therefore, B is the correct answer as it specifically refers to the type of muscle tissue that is under voluntary control.

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.

Correct Answer: B

Rationale: The correct answer is B: Vitamin K. Vitamin K is essential for blood clotting as it helps in the production of certain proteins necessary for the process. Vitamin C (choice A) is important for the immune system and collagen synthesis, not blood clotting. Vitamin A (choice C) plays a role in vision and skin health. Vitamin D (choice D) is mainly involved in calcium absorption and bone health, not blood clotting. Therefore, the correct choice is Vitamin K as it directly supports the clotting process by aiding in protein production.

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: A

Rationale: The primary function of the cardiovascular system is to transport oxygen and nutrients to cells throughout the body. This is achieved through the circulation of blood by the heart and blood vessels. Oxygen is vital for cellular respiration, and nutrients are essential for cell function. Regulating body temperature is primarily the role of the integumentary and nervous systems, not the cardiovascular system. Removing waste products is mainly the function of the excretory system. Hormone production is primarily controlled by the endocrine system, not the cardiovascular system. Therefore, choice A is correct as it directly aligns with the main purpose of the cardiovascular system.