Quizlet HESI A2 Anatomy and Physiology

Correct Answer: B

Rationale: The correct answer is B: To protect the body from external damage. The skin acts as a physical barrier, preventing harmful substances from entering the body and protecting internal organs. It also helps regulate body temperature to some extent, but that is not its primary function. The skin does not produce vitamin D; this is mainly done by the liver and kidneys. Red blood cells are produced in the bone marrow, not the skin.

Correct Answer: A

Rationale: The correct answer is A: Pineal gland. The pineal gland is located in the brain and is responsible for producing melatonin, which regulates sleep-wake cycles. Melatonin is not produced by the thyroid gland (B), pituitary gland (C), or adrenal gland (D). The thyroid gland produces hormones that regulate metabolism, the pituitary gland regulates various hormones, and the adrenal gland produces hormones like cortisol and adrenaline. Therefore, the pineal gland is the correct answer as it specifically produces melatonin.

Correct Answer: B

Rationale: The correct answer is B: Pharynx. The pharynx is a structure found in the upper respiratory tract, specifically connecting the nasal cavity and the larynx. It serves as a passage for air and food. The larynx (A) is also part of the upper respiratory tract, housing the vocal cords. The esophagus (C) is part of the digestive system, not the respiratory tract. The trachea (D) is located below the larynx and is considered part of the lower respiratory tract. Therefore, the pharynx is the correct choice for a structure found in the upper respiratory tract.

Correct Answer: B

Rationale: The correct answer is B: To exchange gases. Alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place. Oxygen from the air we breathe enters the blood through the alveoli, and carbon dioxide is removed from the blood and exhaled. This process is essential for respiration. Explanation of other choices: A: To filter blood - This is incorrect because the alveoli do not filter blood. Filtering of blood primarily occurs in the kidneys and liver. C: To transport nutrients - This is incorrect because the alveoli are not involved in transporting nutrients. Nutrient transport mainly occurs through the bloodstream. D: To store oxygen - This is incorrect because the alveoli do not store oxygen. Oxygen is temporarily stored in the red blood cells and muscle tissues.

Correct Answer: B

Rationale: The primary function of the circulatory system is to transport oxygen and nutrients throughout the body. The heart pumps blood containing oxygen and nutrients to all cells and tissues. This process supports cellular functions and provides energy. Hormone production (A) is mainly regulated by the endocrine system. Fighting infections (C) is primarily the role of the immune system. Regulating body temperature (D) is primarily controlled by the thermoregulatory system. Overall, the circulatory system's main role is the transport of oxygen and nutrients, making choice B the correct answer.