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Which statement correctly matches the valve with its function in the heart?
- A. The aortic valve allows oxygenated blood to flow from the left ventricle to the rest of the body.
- B. The mitral valve opens to allow blood flow from the left atrium to the left ventricle.
- C. The pulmonic valve allows deoxygenated blood to flow from the right ventricle to the pulmonary artery.
- D. The tricuspid valve allows deoxygenated blood to flow from the right atrium to the right ventricle.
Correct Answer: A
Rationale: The correct answer is A. The aortic valve allows oxygenated blood to flow from the left ventricle to the rest of the body. When the left ventricle contracts, the aortic valve opens to allow blood to be pumped into the aorta, the body's main artery that carries oxygen-rich blood to various parts of the body. Choices B, C, and D are incorrect because they do not match the described functions of the mitral, pulmonic, and tricuspid valves, respectively. The mitral valve controls the flow of blood between the left atrium and left ventricle, the pulmonic valve regulates the flow of blood from the right ventricle to the pulmonary artery, and the tricuspid valve manages the blood flow between the right atrium and right ventricle.
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Which of the following correctly lists the normal blood flow through the heart?
- A. Left ventricle, left atrium, body, right ventricle, right atrium, lungs
- B. Left atrium, left ventricle, lungs, right atrium, right ventricle, body
- C. Right atrium, right ventricle, lungs, left atrium, left ventricle, body
- D. Right ventricle, right atrium, body, left atrium, left ventricle, lungs
Correct Answer: B
Rationale: The correct order of normal blood flow through the heart is as follows: from the body, blood flows into the right atrium, then to the right ventricle, followed by the lungs through the pulmonary artery for oxygenation. Oxygenated blood then returns to the heart through the pulmonary veins into the left atrium, then moves into the left ventricle before being pumped out to the body. Choice B correctly depicts this sequential flow of blood through the heart. Choices A, C, and D are incorrect as they do not follow the typical path of blood flow through the heart.
Which of the following structures is the natural pacemaker of the heart?
- A. Sinoatrial node
- B. Submental node
- C. Atrioventricular node
- D. Scalene node
Correct Answer: A
Rationale: The sinoatrial (SA) node is often referred to as the natural pacemaker of the heart because it is a group of cells located in the right atrium responsible for initiating the electrical signals that coordinate the heart's contractions. The SA node sets the rate and rhythm of the heartbeats, making it a crucial component in the heart's function. The other options, Submental node, Atrioventricular node, and Scalene node, are not related to the regulation of the heart's electrical activity. The Submental node is a lymph node located under the chin, the Atrioventricular node is responsible for passing electrical signals from the atria to the ventricles, and the Scalene node does not exist in the context of the heart's electrical system.
Long bones are one of the five major types of bones in the human body. All of the following bones are long bones, EXCEPT
- A. Thighs
- B. Forearms
- C. Ankles
- D. Fingers
Correct Answer: D
Rationale: Long bones are one of the five major types of bones in the human body, characterized by their elongated shape. Thighs, forearms, and ankles are examples of long bones as they are longer than they are wide and have a tubular structure, aiding in support and movement. Fingers, however, are categorized as short bones due to their small size and shape. Short bones like fingers are essential for providing dexterity and precise movements rather than supporting weight or acting as levers for movement. Therefore, the correct answer is D, Fingers, as they are not classified as long bones.
Which of the following statements best defines an organelle?
- A. Layer of polysaccharides outside the plasma membrane of cells.
- B. Abnormal infectious proteins.
- C. Specialized structures within a cell.
- D. Collection of tissues used to serve a specific function.
Correct Answer: C
Rationale: The correct answer is C: 'Specialized structures within a cell.' An organelle is a specialized subunit within a cell that has a specific function. Organelles are membrane-bound structures found within the cytoplasm of eukaryotic cells, each performing distinct roles that contribute to the overall functioning of the cell. Choices A, B, and D are incorrect. Option A describes the glycocalyx, which is a layer of polysaccharides outside the plasma membrane of cells. Option B refers to prions, abnormal infectious proteins. Option D defines an organ, a collection of tissues used to serve a specific function, rather than an organelle within a cell.
The chemical equation below is unbalanced. When it is properly balanced, how many molecules of carbon dioxide (CO2) are produced for each molecule of propane (C3H8) in the reaction? 3C3H8 + 5O2 → 3CO2 + 4H2O
- A. One Half.
- B. Two.
- C. Three.
- D. Five.
Correct Answer: B
Rationale: The balanced chemical equation for the combustion of propane is: 3C3H8 + 5O2 → 3CO2 + 4H2O. This equation shows that for every 3 molecules of propane (C3H8) consumed, 3 molecules of carbon dioxide (CO2) are produced. Therefore, when properly balanced, 3CO2 are produced for each molecule of propane used. Thus, the correct answer is B: Two. Choices A, C, and D are incorrect because they do not reflect the correct stoichiometry as determined by the balanced equation.