HESI A2 Anatomy and Physiology Quizlet 2024

Correct Answer: C

Rationale: The correct answer is C: Inflammation. Inflammation is a secondary defense mechanism that occurs when tissues are injured, triggering a response to remove harmful stimuli and promote healing. It involves increased blood flow, white blood cell migration, and release of cytokines. Tears (A) and mucus (D) are primary defenses that help prevent pathogens from entering the body. Urine (B) is not a defense mechanism but rather a waste product excreted by the kidneys. In summary, inflammation plays a crucial role in fighting pathogens by mobilizing the immune system, making it the correct secondary defense mechanism choice.

Correct Answer: A

Rationale: The correct answer is A because endocytosis is a process in which the cell engulfs solid particles by forming vesicles around them. This allows the cell to bring in large molecules or particles that are too big to pass through the cell membrane on their own. Choice B is incorrect because endocytosis involves engulfing solid particles, not liquid material. Choice C is incorrect because endocytosis is about bringing particles into the cell, not expelling them. Choice D is incorrect because endocytosis involves the cell taking in material, not releasing it.

Correct Answer: C

Rationale: The correct answer is C because the intercostal muscles assist with respiration by enlarging and reducing the space in the thorax during inhalation and exhalation. During inhalation, these muscles contract to lift the ribcage, expanding the thoracic cavity to allow the lungs to fill with air. During exhalation, they relax to decrease the thoracic cavity size, helping to expel air from the lungs. Choice A is incorrect because the intercostal muscles do not directly protect the delicate bronchioles and alveoli. Choice B is incorrect as these muscles do not signal a decrease in intra-alveolar pressure. Choice D is incorrect because the primary function of the intercostal muscles is not to maintain a medial separation between pleurae.

Correct Answer: D

Rationale: The correct answer is D: Alveoli. Alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide between air and blood occurs. This is where oxygen is taken up by the blood and carbon dioxide is released into the air. Pleura (A) is the membrane surrounding the lungs, trachea (B) is the windpipe, and bronchioles (C) are smaller airways within the lungs that lead to the alveoli but do not participate directly in gas exchange. Therefore, the alveoli are the site where nearly all gaseous exchanges between air and blood take place in the lungs.

Correct Answer: C

Rationale: When the pulmonary valve and aortic valves are open, blood can flow between the heart and the rest of the body. The pulmonary valve allows blood to flow from the right ventricle to the lungs, while the aortic valve allows blood to flow from the left ventricle to the rest of the body. Therefore, when both valves are open, blood is being pumped out of the heart to circulate throughout the body. Choices A, B, and D are incorrect because they do not describe the specific pathway of blood flow when the pulmonary and aortic valves are open.