HESI A2 Anatomy and Physiology Practice Test

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: D

Rationale: The correct answer is D: the radius. The axial skeletal system consists of the skull, ribs, and breastbone, which are all located along the body's central axis. The radius is actually part of the appendicular skeletal system, specifically a bone in the forearm, not part of the axial skeleton. It plays a role in forearm rotation and helps to form the elbow joint. Therefore, the radius is not part of the axial skeletal system, making choice D the correct answer.

Correct Answer: C

Rationale: The correct answer is C: anterior. The ribs are located in front of the lungs, making them anterior to the lungs. This is because when referring to anatomical positions, anterior means towards the front of the body. Ribs protect and support the lungs, which are situated deeper in the body. Choices A, B, and D are incorrect because the ribs are not positioned medially, superiorly, or deeply in relation to the lungs. Medial refers to being towards the midline of the body, superior means above, and deep indicates being further away from the surface. Therefore, the most accurate description of the relationship between the ribs and lungs is that the ribs are anterior to the lungs.

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.

Correct Answer: D

Rationale: The correct answer is D because a cut through the transverse plane divides the body into superior and inferior parts. This is a true cross-section, providing a view of structures perpendicular to the long axis of the body. Choices A, B, and C do not result in a true cross-section as they do not divide the body into distinct superior and inferior parts. A sagittal or frontal section (choice A) divides the body into left and right or front and back parts, a cut along the coronal plane (choice B) divides the body into anterior and posterior parts, and a cut along the median plane (choice C) divides the body into equal left and right halves.