Nokea
Where does gas exchange occur in the human body?
- A. Alveoli
- B. Bronchi
- C. Larynx
- D. Pharynx
Correct Answer: A
Rationale: The correct answer is A: Alveoli. Gas exchange occurs in the alveoli, which are tiny air sacs in the lungs. Oxygen from the air we breathe diffuses into the blood vessels surrounding the alveoli, while carbon dioxide from the blood diffuses into the alveoli to be exhaled. The bronchi, larynx, and pharynx are all part of the respiratory system but are not directly involved in gas exchange. The bronchi are airways that lead to the lungs, the larynx is the voice box, and the pharynx is the throat. These structures are important for breathing and vocalization but do not participate in the exchange of gases between the respiratory system and the circulatory system.
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An atom has 5 protons, 5 neutrons, and 6 electrons. What is the electric charge of this atom?
- A. Neutral
- B. Positive
- C. Negative
- D. Undetermined
Correct Answer: C
Rationale: The correct answer is 'Negative.' An atom becomes negatively charged when it has more electrons than protons. In this case, the atom has 6 electrons and 5 protons, resulting in a net negative charge. Choice A 'Neutral' is incorrect because the atom is not balanced in terms of protons and electrons. Choice B 'Positive' is incorrect because having more electrons than protons results in a negative charge. Choice D 'Undetermined' is incorrect, as the charge can be determined based on the relative number of protons and electrons.
Which of the following body systems controls fluid loss, protects deep tissues, and synthesizes vitamin D?
- A. The skeletal system
- B. The muscular system
- C. The lymphatic system
- D. The integumentary system
Correct Answer: D
Rationale: The integumentary system is responsible for controlling fluid loss through sweat, protecting deep tissues as the body's first line of defense, and synthesizing vitamin D when exposed to sunlight. The skin, hair, nails, and associated glands make up the integumentary system, which plays a crucial role in maintaining homeostasis and overall health. The skeletal system (Choice A) provides structural support and protection for internal organs but does not directly control fluid loss, protect deep tissues, or synthesize vitamin D. The muscular system (Choice B) is responsible for movement and stability but is not involved in the functions described. The lymphatic system (Choice C) is primarily responsible for immunity and fluid balance, not the specific functions mentioned in the question.
Which of the following choices best describes the location of the trachea in relation to the esophagus?
- A. Lateral
- B. Anterior
- C. Posterior
- D. Dorsal
Correct Answer: B
Rationale: The trachea is situated in front of the esophagus, making it anterior to the esophagus. This anatomical relationship is crucial to understand in clinical practice, particularly regarding airway management and esophageal intubation. Therefore, the correct answer is B: 'Anterior.' Choices A, C, and D are incorrect because the trachea is not located to the side (lateral), behind (posterior), or on the back (dorsal) of the esophagus.
What type of immunity is acquired through vaccination?
- A. Passive natural immunity
- B. Active natural immunity
- C. Active artificial immunity
- D. Passive artificial immunity
Correct Answer: C
Rationale: The correct answer is C, Active artificial immunity. Vaccination introduces a weakened or inactive form of the pathogen to stimulate the immune system, leading to the development of immunity. Active artificial immunity is the result of deliberate exposure to an antigen, such as through vaccination, to produce an immune response. Passive immunity, like receiving pre-formed antibodies, does not involve the immune system's activation. Natural immunity is typically acquired through exposure to the pathogen itself, not through vaccination.
Which blood vessel carries oxygenated blood back to the heart?
- A. Pulmonary vein
- B. Pulmonary artery
- C. Aorta
- D. Superior vena cava
Correct Answer: A
Rationale: The corrected question is asking for a blood vessel that carries oxygenated blood back to the heart. The pulmonary vein is the correct choice as it carries oxygenated blood from the lungs back to the heart during systemic circulation. The pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation. The aorta is the main artery that carries oxygenated blood away from the heart to the body. The superior vena cava returns deoxygenated blood from the upper body back to the heart.