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: Nervous system. The nervous system is primarily responsible for integrating voluntary movements as it consists of the brain and spinal cord, which control voluntary actions through the transmission of electrical signals to muscles. The cardiovascular system (A), digestive system (B), and respiratory system (C) are not directly involved in controlling voluntary movements, making them incorrect choices.

Correct Answer: D

Rationale: The correct answer is D: Scurvy. Vitamin C deficiency leads to scurvy due to its role in collagen synthesis. Without enough vitamin C, collagen production is disrupted, leading to symptoms like gum disease, easy bruising, and poor wound healing. Kwashiorkor (A) is caused by severe protein deficiency. Pellagra (B) results from niacin (vitamin B3) deficiency. Rickets (C) is caused by vitamin D deficiency, leading to weak or soft bones. In summary, scurvy is the correct answer due to the specific symptoms associated with vitamin C deficiency, while the other choices are related to deficiencies of different nutrients and have distinct clinical presentations.

Correct Answer: A

Rationale: The correct answer is A: Hormones. Hormones are chemical messengers that are produced by endocrine glands and control growth, differentiation, and metabolism of specific target cells. They are released into the bloodstream and travel to target cells to elicit a response. Neurons (B) are nerve cells that transmit electrical signals, not chemical messengers. Glands (C) are structures that produce and secrete substances, including hormones, but they are not the chemical messengers themselves. Second messengers (D) are molecules involved in signal transduction pathways within cells, not the primary chemical messengers that control growth, differentiation, and metabolism.

Correct Answer: B

Rationale: The correct answer is B: Transverse. A transverse plane, also known as a horizontal plane, divides the body into upper (superior) and lower (inferior) portions. This plane would be used to separate the abdominal cavity from the thoracic cavity because it runs horizontally across the body at the level of the diaphragm, which separates these two cavities. The other choices are incorrect because: A: Sagittal plane divides the body into left and right portions. C: Frontal plane divides the body into front (anterior) and back (posterior) portions. D: Coronal plane is not a recognized anatomical term and is often used interchangeably with frontal plane.