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: 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: 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: A

Rationale: The correct answer is A: The nose. The nose is an anterior feature of the human head as it is located at the front of the face. The nose plays a crucial role in breathing and smelling. B: The ears are located on the sides of the head, not at the front, making it an incorrect choice. C: The occipital lobe is a part of the brain located at the back of the head, not the front, making it an incorrect choice. D: The temporal lobe is also a part of the brain located on the sides of the head, not the front, making it an incorrect choice.