BSC 109 Lecture Notes - Lecture 28: Metabolic Waste, Integumentary System, Respiratory System
BSC 109 Chapter 15 Part 1
The Urinary System
October 24, 2016
Urinary System Contributes to Homeostasis
• Excretion: processes that remove wastes and excess materials from the body
- Digestive system: excretes food residues and wastes produced by the liver
- Respiratory system (lungs): excretes carbon dioxide
- Integumentary system (skin): excretes water, salt
- Urinary system (kidneys): excretes nitrogenous wastes, excess solutes, and water
The Kidneys Regulate Water Levels
• To maintain homeostasis
- Water Intake = Water Output
• Kidneys adjust water output as necessary
- Water input: food, drink, metabolism
- Water output: lungs, skin, feces
- Kidneys modify output based on intake and loss
- Output varies from ½ liter/day to 1 liter/hour
Food is water output
To get rid of water, we exhale h2o, we sweat, and some of our feces contain water but
most comes through urine
As the input/output factors vary, the kidneys modify to make sure we are getting the
nutrients we need
Table 15.1 Sources of Water Gain and Loss Per Day
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Document Summary
Urinary system contributes to homeostasis: excretion: processes that remove wastes and excess materials from the body. Digestive system: excretes food residues and wastes produced by the liver. Urinary system (kidneys): excretes nitrogenous wastes, excess solutes, and water. The kidneys regulate water levels: to maintain homeostasis. Water intake = water output: kidneys adjust water output as necessary. Kidneys modify output based on intake and loss. Output varies from liter/day to 1 liter/hour. To get rid of water, we exhale h2o, we sweat, and some of our feces contain water but most comes through urine. As the input/output factors vary, the kidneys modify to make sure we are getting the nutrients we need. Table 15. 1 sources of water gain and loss per day. It is important the we lose the same amount of water as we gain. Our urine level will be modified to equal that of our output or our gain.