Blood Pressure Regulators
The body is composed of systems that have evolved and diversified in order to maintain the natural functions and processes they regulate. One such system that has these regulators is the bodyâìĄ¢s cardiovascular system. The bodyâìĄ¢s pump, which regulates the flow of vitally needed oxygen to all cells of the body, as well as the discard of carbon dioxide and other waste products, is the heart.
Because blood pressure varies at different points within the body, differing components are needed to keep the bodyâìĄ¢s blood pressure regulated. Three of the basic components are baroreceptors, chemoreceptors, and the kidneys.
Baroreceptors are stretch receptors composed of fine branching nerve endings and are contained along the walls of the arteries near the heart and in other areas of the body as well. Impulses are related to this stretching along the arterial walls, which causes these baroreceptors to send out even more impulses to the heart, arteries, and veins, causing the blood pressure to go either up or down.
Chemoreceptors are located along the walls of the arteries and monitor changes in oxygen level, carbon dioxide, and pH. Just think! A fall in oxygen causes receptors to send impulses to raise the blood pressure.
The kidneys play a role in regulating blood pressure by absorbing salts and water and removing wastes. Hormones secreted by the adrenal cortex cause the kidney to keep or let go of any salt and water. This has an influence on blood volume and consequently on blood pressure.
What is the meaning of the word 'evolved' in the first paragraph?
Correct Answer: B
Rationale: The correct answer is B: 'To gradually develop.' In the context of the paragraph, 'evolved' refers to the natural progression and development of the body's systems over time. The word 'evolved' signifies a process of gradual advancement and adaptation, which aligns with the concept of the systems developing to maintain natural functions. The other choices do not accurately reflect the intended meaning of 'evolved' in this context.
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