CK12 Life Science

illness and death of cells, tissues, and organs. The organs of your excretory system help to
keep the correct balance of water and salts within your body.

Your body also needs to remove the wastes that build up from the metabolic activity of cells
and digestion. These wastes include carbon dioxide, urea, and certain plant materials. If
these wastes were not removed, your cells would stop working and you would get very sick.
In this lesson you will learn how waste is removed from the body, and how the kidneys filter
waste from the blood.

The Excretory System

The excretory systemis the organ system that maintains homeostasis by keeping the
correct balance of water and salts in your body. It also helps to release wastes from the
body. Excretionis the process of removing wastes from the body. The organs of the
excretory system are also parts of other organ systems. For example, your lungs are part of
the respiratory system. Your lungs remove carbon dioxide from your body so they are also
part of the excretory system. More organs of the excretory system, and the other organs
systems of which they are part are listed inTable(19.1).

Table 1: Organs of the Excretory System

Table 19.1: Organs of the Excretory System

Organ(s) Function Other Organ System of

which it is Part

Lungs Remove carbon dioxide Respiratory system

Skin Sweat glands remove water,

salts, and other wastes

Integumentary system

Large intestine Removes solid waste and

some water in the form of fe-

ces

Digestive system

Kidneys Remove urea, salts, and ex-

cess water from the blood

Urinary system

Functions of the Excretory System

The excretory system controls the chemical make-up of body fluids. The organs of the
excretory system remove metabolic wastes. They also maintain the proper concentrations of
water, salts, and nutrients in the body. In this way the excretory system has an important
homeostatic job.

Your body takes nutrients from food and uses them for energy, growth, and repair. After