What are the two primary functions of the respiratory system?
- A. Delivering nutrients and removing CO2
- B. Delivering O2 and removing CO2, maintaining blood pH
- C. Maintaining blood pH and delivering nutrients
- D. Delivering O2 and nutrients to the cells
Correct Answer: B
Rationale: The correct answer is B. The respiratory system's primary functions include delivering oxygen (O2) to the body's cells for cellular respiration and removing carbon dioxide (CO2), thereby aiding in the maintenance of blood pH. These functions are crucial for gas exchange and the overall metabolic processes within the body. Choice A is incorrect as the respiratory system primarily delivers O2, not nutrients, and removes CO2, not delivering it. Choice C is incorrect as while the respiratory system helps maintain blood pH by removing CO2, it does not primarily deliver nutrients. Choice D is incorrect as it combines the functions of delivering O2 and nutrients, which are distinct roles of different systems in the body.
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How does ingested food move through the digestive tract?
- A. Chewing, digestion, absorption
- B. Swallowing, peristalsis, segmentation
- C. Swallowing, mastication, defecation
- D. Digestion, absorption, excretion
Correct Answer: B
Rationale: The correct answer is B: Swallowing, peristalsis, segmentation. Food moves through the digestive tract by first being swallowed, then undergoing peristalsis (wave-like movements that propel food along the digestive tract), and finally undergoing segmentation (mixing movements in the intestines). Chewing and digestion occur in the mouth and stomach, respectively, while absorption and excretion happen later in the digestive process. Choice A is incorrect as absorption is a later stage in the process. Choice C is incorrect because defecation is the elimination of waste, not the movement of food. Choice D is incorrect as excretion is the elimination of waste products, not the movement of ingested food through the digestive tract.
Which type of tissue provides support and structure to the body?
- A. Muscle tissue
- B. Connective tissue
- C. Nervous tissue
- D. Epithelial tissue
Correct Answer: B
Rationale: Connective tissue is the correct answer as it provides support, structure, and strength to the body by holding tissues and organs in place. Muscle tissue is primarily responsible for movement, nervous tissue for communication, and epithelial tissue for covering and lining surfaces. While muscle tissue allows for voluntary and involuntary movement, nervous tissue transmits electrical signals, and epithelial tissue acts as a protective barrier and is involved in absorption and secretion. Therefore, in the context of providing support and structure, connective tissue is the most appropriate choice.
Which structure of the respiratory system bifurcates into the primary bronchi?
- A. Trachea
- B. Alveoli
- C. Bronchioles
- D. Larynx
Correct Answer: A
Rationale: The trachea is the structure that bifurcates into the primary bronchi. The trachea is a tube that carries air to and from the lungs. It divides into the left and right primary bronchi at a specific point called the carina, which then further divide into secondary and tertiary bronchi, leading to the bronchioles. The alveoli are the tiny air sacs at the end of the bronchioles where gas exchange occurs, not the structure that bifurcates into the primary bronchi. Bronchioles are smaller airway branches that come after the bronchi but do not bifurcate into them. The larynx, also known as the voice box, is located above the trachea and is responsible for sound production, not the bifurcation into primary bronchi. Therefore, the correct answer is the trachea.
What is the function of the myelin sheath in a neuron?
- A. To transmit electrical impulses
- B. To insulate and speed up electrical signals
- C. To produce neurotransmitters
- D. To protect the neuron from damage
Correct Answer: B
Rationale: The myelin sheath serves to insulate neurons and accelerate the transmission of electrical signals along the axon. This insulation helps in the efficient conduction of nerve impulses by preventing signal loss or leakage. Choice A is incorrect because the myelin sheath does not transmit electrical impulses itself but rather helps in the conduction. Choice C is incorrect as the myelin sheath is not responsible for producing neurotransmitters. Choice D is also incorrect as the primary function of the myelin sheath is not to protect the neuron from damage. Therefore, the correct answer is B, as it accurately describes the function of the myelin sheath in a neuron.
How does AIDS impair the immune system?
- A. AIDS targets and destroys Helper T-Cells, preventing the activation of Cytotoxic T-Cells or B-Cells.
- B. IgE stimulates mast cells to release excessive histamine.
- C. IgE inhibits mast cells from releasing sufficient histamine.
- D. Helper T-Cells deceive the body into attacking itself.
Correct Answer: A
Rationale: AIDS targets and destroys Helper T-Cells, which play a crucial role in coordinating the immune response. By affecting these cells, AIDS prevents the activation of other important immune cells like Cytotoxic T-Cells or B-Cells. This disruption in the immune system's communication and response mechanisms leads to immune system failure and increased vulnerability to infections. Choices B and C are incorrect because they refer to the role of IgE in allergic reactions, which is not directly related to how AIDS impairs the immune system. Choice D is also incorrect as Helper T-Cells being destroyed in AIDS is not about deceiving the body into attacking itself, but rather the direct impact on immune system function.
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