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: D

Rationale: The upper respiratory tract consists of the nose, nasal cavity, pharynx, and larynx. Bronchioles, alveolar ducts, and alveoli are all part of the lower respiratory tract, involved in gas exchange within the lungs. Therefore, none of the above options are part of the upper respiratory tract. The correct answer is D.

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: Sensory neuron. This is because sensory neurons carry impulses from sense receptors to the central nervous system, such as the spinal cord. Motor neurons carry impulses away from the central nervous system to effectors (muscles or glands). Interneurons are found within the central nervous system and facilitate communication between sensory and motor neurons. Bipolar neurons have two processes (dendrite and axon) and are typically found in specialized sensory organs like the retina. Therefore, the impulse traveling from a sense receptor to the spinal cord is specifically carried by a sensory neuron.