Nokea
What happens to the diaphragm during inspiration?
- A. It moves upward
- B. It moves downward
- C. It expands
- D. It contracts and moves downward
Correct Answer: D
Rationale: During inspiration, the diaphragm contracts and moves downward. This action increases the volume of the thoracic cavity, which lowers the air pressure inside the lungs, allowing air to flow in. The downward movement and contraction of the diaphragm create the necessary space for the lungs to expand and fill with air. Choice A, 'It moves upward,' is incorrect as the diaphragm moves downward. Choice B, 'It moves downward,' is partially correct but misses the contraction aspect. Choice C, 'It expands,' is incorrect as the diaphragm itself does not expand during inspiration. Therefore, choice D, 'It contracts and moves downward,' is the most accurate description of the diaphragm's action during inspiration.
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Which of the following correctly identifies a difference between the primary and secondary immune response?
- A. In the secondary response, macrophages migrate to the lymph nodes to present the foreign microorganism to helper T lymphocytes.
- B. The humoral immunity that characterizes the primary response is coordinated by B lymphocytes.
- C. The primary response is quicker and more powerful than the secondary response.
- D. Suppressor T cells are activated in the secondary response to prevent an overactive immune response.
Correct Answer: C
Rationale: The correct answer is C. The primary immune response is slower and less powerful compared to the secondary immune response. During the primary response, immune cells encounter the antigen for the first time, necessitating the activation and proliferation of specific immune cells. In contrast, the secondary response benefits from memory cells that quickly recognize the antigen, enabling a faster and more potent immune response. Choices A, B, and D are incorrect. While macrophages play a role in presenting antigens to T cells, this is not a defining difference between primary and secondary responses. Humoral immunity involves B lymphocytes in both primary and secondary responses, so it does not differentiate the two. Suppressor T cells primarily function to regulate the immune response but are not a key factor distinguishing primary from secondary responses.
Where does sperm production occur?
- A. Prostate gland
- B. Seminal vesicles
- C. Scrotum
- D. Seminiferous tubules
Correct Answer: D
Rationale: Sperm production occurs in the seminiferous tubules within the testes. These tubules are responsible for spermatogenesis, the process of sperm creation. The prostate gland and seminal vesicles contribute to seminal fluid production, while the scrotum houses the testes but does not produce sperm. Therefore, choices A, B, and C are incorrect as they are not sites for sperm production.
Which valve prevents the return of blood into the right ventricle?
- A. Pulmonary semilunar valve
- B. Aortic semilunar valve
- C. Tricuspid valve
- D. Mitral valve
Correct Answer: A
Rationale: The correct answer is A: Pulmonary semilunar valve. The pulmonary semilunar valve is located between the right ventricle and the pulmonary artery. It opens to allow blood to be pumped into the pulmonary artery but closes to prevent blood from returning back into the right ventricle. The aortic semilunar valve is located between the left ventricle and the aorta. The tricuspid valve is located between the right atrium and right ventricle, and the mitral valve is located between the left atrium and left ventricle. Therefore, the pulmonary semilunar valve is the specific valve responsible for preventing the backflow of blood into the right ventricle during the cardiac cycle.
What is the pathway of deoxygenated blood in our body?
- A. From the lungs to the left ventricle
- B. From the body to the right atrium, then to the right ventricle, and finally to the lungs
- C. From the left atrium to the body
- D. From the aorta to the right atrium
Correct Answer: B
Rationale: The correct pathway of deoxygenated blood in our body involves blood returning from the body, entering the right atrium, then passing to the right ventricle, and eventually reaching the lungs for oxygenation. This sequence ensures that deoxygenated blood is pumped to the lungs, where it receives oxygen and releases carbon dioxide before circulating back to the body. Choices A, C, and D are incorrect because they do not follow the actual path of deoxygenated blood in the circulatory system.
Which structure in the digestive system absorbs the most nutrients?
- A. Stomach
- B. Small intestine
- C. Large intestine
- D. Esophagus
Correct Answer: B
Rationale: The small intestine is the primary site where the absorption of nutrients from digested food occurs. Its large surface area, specialized cells, and villi play key roles in maximizing nutrient absorption, making it the structure in the digestive system that absorbs the most nutrients. The stomach's main function is to break down food with acid and enzymes, not absorb nutrients. The large intestine primarily absorbs water and electrolytes, not nutrients. The esophagus is a muscular tube that connects the throat with the stomach and does not play a role in nutrient absorption.