Connection for AP® Courses
As we learned in an earlier section, the excretory system works with the circulatory and endocrine systems to maintain osmotic balance, eliminate wastes, and maintain blood pressure. For AP®, you do not need to memorize the list of hormones that control osmoregulatory functions or their specific function(s). However, information in this section applies to concepts previously explored.
The kidneys synchronize with hormonal cues. As you recall from our study of the endocrine system, hormones are small messenger molecules that travel in the bloodstream to affect a target cell. Different regions of the nephron have specialized cells with receptors to respond to chemical messengers and hormones. Table 32.1 summarizes the hormones that control the osmoregulatory functions. For example, the flight/flight hormones epinephrine and norepinephrine, released by the adrenal medulla and nervous subsystem, respectively, halt kidney function temporarily when the body is under extreme stress and much of the body’s energy is used to combat imminent danger. Another example is the rennin-angiotensin-aldosterone system that increases blood pressure and volume primarily by constricting blood vessels. Another hormone, antidiuretic hormone (ADH) increases membrane permeability to water in the collecting ducts of the nephron by adding aquaporins, causing more water to be reabsorbed. You’ve experienced the effects of ADH when it’s hot outside and you’re running around the athletic field; since you’re losing water by sweating and breathing hard, ADH prevents you from losing more water in urine and risking dehydration.
Information presented and the examples highlighted in the section support concepts outlined in Big Idea 3 of the AP® Biology Curriculum Framework. The AP® Learning Objectives listed in the Curriculum Framework provide a transparent foundation for the AP® Biology course, an inquiry-based laboratory experience, instructional activities, and AP® exam questions. A learning objective merges required content with one or more of the seven science practices.
Big Idea 3 |
Living systems store, retrieve, transmit and respond to information essential to life processes. |
Enduring Understanding 3.D |
Cells communicate by generating, transmitting and receiving chemical signals. |
Essential Knowledge
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3.D.2
Cells communicate with each other through direct contact with other cells or from a distance via chemical signaling.
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Science Practice |
6.2
The student can construct explanations of phenomena based on evidence produced through scientific practices.
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Learning Objective |
3.34
The student is able to construct explanations of cell communication through cell-to-cell direct contact or through chemical signaling.
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Essential Knowledge
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3.D.2
Cells communicate with each other through direct contact with other cells or from a distance via chemical signaling.
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Science Practice |
1.1
The student can create representations and models of natural or man-made phenomena and systems in the domain.
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Learning Objective |
3.35
The student is able to create representation(s) that depict how cell-to-cell communication occurs by direct contact or from a distance through chemical signaling.
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