HESI A2 Anatomy and Physiology Practice Test

Correct Answer: A

Rationale: Smooth muscles are involved in peristalsis as they are found in the walls of the digestive tract and exhibit rhythmic contractions to propel food along the digestive system. Smooth muscles are involuntary, allowing for automatic control of peristalsis without conscious effort. Cardiac muscles (B) are found in the heart and are responsible for pumping blood, not peristalsis. Skeletal muscles (C) are voluntary and are not directly involved in peristalsis. Epaxial muscles (D) are a specific group of skeletal muscles located along the vertebral column and are not involved in peristalsis.

Correct Answer: D

Rationale: The correct answer is D because the coronary artery supplies oxygenated blood to the heart muscle, ensuring proper nourishment and functioning of the heart. This is vital for maintaining cardiac health. Explanation: 1. The coronary artery is responsible for delivering blood to the heart muscle specifically. 2. The heart muscle needs a rich blood supply to function optimally. 3. If the coronary artery fails to supply blood to the heart muscle, it can lead to serious conditions like heart attacks. 4. Choices A, B, and C are incorrect because they do not accurately reflect the specific function of the coronary artery in supplying blood to the heart muscle.

Correct Answer: D

Rationale: The correct answer is D: Progesterone. Progesterone is the hormone that initiates the preparation of the endometrium for pregnancy by promoting the thickening of the uterine lining and creating a suitable environment for implantation. It is produced by the corpus luteum after ovulation and plays a crucial role in maintaining the uterine lining during early pregnancy. A: FSH (Follicle-stimulating hormone) is responsible for stimulating the growth of ovarian follicles but does not directly prepare the endometrium for pregnancy. B: Estrogen helps in the growth and development of the endometrium but is not the hormone that specifically initiates its preparation for pregnancy. C: LH (Luteinizing hormone) triggers ovulation and the formation of the corpus luteum, which then produces progesterone. While LH is important in the menstrual cycle, it does not directly initiate endometrial preparation.

Correct Answer: A

Rationale: Smooth muscles are involved in peristalsis as they are found in the walls of the digestive tract and exhibit rhythmic contractions to propel food along the digestive system. Smooth muscles are involuntary, allowing for automatic control of peristalsis without conscious effort. Cardiac muscles (B) are found in the heart and are responsible for pumping blood, not peristalsis. Skeletal muscles (C) are voluntary and are not directly involved in peristalsis. Epaxial muscles (D) are a specific group of skeletal muscles located along the vertebral column and are not involved in peristalsis.

Correct Answer: A

Rationale: The correct answer is A: Potassium. Potassium is an essential mineral that plays a vital role in maintaining fluid balance in the body by regulating the movement of fluids in and out of cells. It helps to control blood pressure, muscle contractions, and nerve impulses. Cobalt, chromium, and sulfur do not have a direct role in fluid balance regulation. Cobalt is needed for B12 synthesis, chromium helps with insulin function, and sulfur is essential for protein structure. Therefore, potassium is the correct choice for maintaining fluid balance in the body.