16.1 Case Study: Waste Management

Created by CK-12 Foundation/Adapted by Christine Miller

Signs for mens and women's washroom.
Figure 16.1.1 Alcohol may increase your visits to the restroom.

Case Study: Drink and Flush

“Wow, this line for the restroom is long!” Shae says to Talia, anxiously bobbing from side to side to ease the pressure in her bladder. Talia nods and says, “It’s always like this at parties. It’s the alcohol.”

Shae and Talia are 21-year-old college students at a party. They — along with the other party guests — have been drinking alcoholic beverages over the course of the evening. As the night goes on, the line for the restroom has gotten longer and longer. You may have noticed this phenomenon if you have been to places where large numbers of people are drinking alcohol, like at the ballpark in Figure 16.1.2.

16.1.2 Bathroom Line up
Figure 16.1.2 A line stretching out of a restroom door at a ballpark.

Shae says, “I wonder why alcohol makes you have to pee?” Talia says she learned about this in her Human Biology class. She tells Shae that alcohol inhibits a hormone that helps you retain water. Instead of your body retaining water, you urinate more out. This could lead to dehydration, so she suggests that after their trip to the restroom, they start drinking water, instead of alcohol.

For people who drink occasionally or moderately, this effect of alcohol on the — the system that removes wastes such as urine — is usually temporary. However, in people who drink excessively, alcohol can have serious, long-term effects on the excretory system. Heavy drinking on a regular basis can cause liver and kidney disease.

As you will learn in this chapter, the and are important organs of the excretory system, and impairment of the functioning of these organs can cause serious health consequences. At the end of the chapter, you will learn which hormone Talia was referring to. You will also learn some of the ways alcohol can affect the excretory system — both after the occasional drink, and in cases of excessive alcohol use and abuse.

Chapter Overview: Excretory System

In this chapter, you will learn about the excretory system, which rids the body of toxic waste products and helps maintain homeostasis. Specifically, you will learn about:

  • The organs of the excretory system —including the skin, liver, large intestine, lungs, and kidneys — that eliminate waste and excess water from the body.
  • How wastes are eliminated through sweat, feces, urine, and exhaled gases.
  • How toxic substances in the blood are broken down by the liver.
  • The urinary system, which includes the kidneys, ureters, bladder, and urethra.
  • The main function of the urinary system, which is to filter the blood and eliminate wastes, mineral ions, and excess water from the body in the form of urine.
  • How the kidneys filter the blood, retain necessary substances, produce urine, and help maintain homeostasis (such as proper ion and water balance).
  • How urine is stored, transported, and released from the body.
  • Disorders of the urinary system, including bladder infections, kidney stones, polycystic kidney disease, urinary incontinence, and kidney damage caused by factors such as uncontrolled diabetes and high blood pressure.

As you read the chapter, think about the following questions:

  1. Which hormone do you think Talia was referring to? Remember that this hormone causes the urinary system to retain water and excrete less water out in urine.
  2. How and where does this hormone work?
  3. Long-term, excessive use of alcohol can affect the liver and kidneys. How do these two organs of excretion interact and work together?


Figure 16.1.1

Gotta Pee [photo] by Jon-Eric Melsæter on Flickr is used under a CC BY 2.0 (https://creativecommons.org/licenses/by/2.0/) license.

Figure 16.1.2

Bathroom line up [photo] by Dorothy on Flickr is used under a CC BY 2.0 (https://creativecommons.org/licenses/by/2.0/) license.


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Human Biology Copyright © 2020 by Christine Miller is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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