HESI A2 Anatomy and Physiology Practice Exam

Correct Answer: C

Rationale: The correct answer is C because the vertebrae of the spine protect the spinal cord, which is a crucial component of the nervous system. The spinal cord carries electrical signals between the brain and the rest of the body, allowing for communication and coordination of movement and sensation. It is essential for the skeletal system to provide protection to vital nervous system structures. A, B, and D are incorrect: A: While bones do provide support for body position, they do not transmit signals to the brain directly. B: While pain nerves within bones can notify the brain of injuries, this is not the primary way the skeletal system works with the nervous system. D: Bone marrow is responsible for producing blood cells, not nerve cells.

Correct Answer: A

Rationale: The correct answer is A: Vitamin B1, which is another name for thiamine. Thiamine is essential for energy metabolism and nerve function. Vitamin B2 (choice B) is riboflavin, Vitamin B6 (choice C) is pyridoxine, and Vitamin D (choice D) is important for bone health. Thiamine deficiency can lead to serious conditions like beriberi, making it crucial for overall health.

Correct Answer: C

Rationale: Trypsin is a digestive enzyme produced in the pancreas that specifically breaks down proteins into smaller peptides. It acts in the small intestine, targeting peptide bonds between amino acids. This process aids in protein digestion and absorption. Choices A, B, and D are incorrect as trypsin does not break down fats, starch, or nucleic acids in the body.

Correct Answer: A

Rationale: Primary peristalsis occurs in the esophagus. This process involves coordinated muscle contractions that push food from the mouth to the stomach. The esophagus contains smooth muscles that contract rhythmically to propel food downwards. In contrast, the stomach's main function is to mix and churn food with gastric juices, not conduct peristalsis. The nervous system plays a role in regulating peristalsis but is not the location where it occurs. The small intestine is primarily involved in digestion and absorption of nutrients, not peristalsis. Therefore, the correct answer is A, as the esophagus is where primary peristalsis takes place.

Correct Answer: D

Rationale: The correct answer is D: Melatonin. The pineal gland is responsible for producing melatonin, a hormone that regulates the sleep-wake cycle. It is released in response to darkness, helping to signal the body that it is time to sleep. Corticosteroid (A) is produced by the adrenal glands, oxytocin (B) is produced by the hypothalamus and released by the pituitary gland, and prolactin (C) is produced by the pituitary gland. Therefore, the correct answer is D as it directly relates to the function of the pineal gland.