Lesson 5 –Lesson 5 –The ExcretoryThe Excretory

SystemSystem

It gets rid of wastes:It gets rid of wastes: solid waste from digestionsolid waste from digestion (through the large (through the large intestine)intestine)

carbon dioxide from cellscarbon dioxide from cells (through the lungs) (through the lungs)

It gets rid of wastes:It gets rid of wastes: liquid waste from cellsliquid waste from cells (through the (through the kidneyskidneys, , whichwhich filter wastes out of the filter wastes out of the bloodblood and then produce urine) and then produce urine)

sweat (through the skin)sweat (through the skin)

Blood passes through theBlood passes through the kidneys 60 times a day. kidneys 60 times a day.

The kidneys remove substancesThe kidneys remove substances the body no longer needs and the body no longer needs and returns substances it does returns substances it does need.need.

NephronNephron – part of the kidney – part of the kidney where wastes are separated where wastes are separated from useful materials from useful materials

Wastes can build up toWastes can build up to dangerous levels. dangerous levels.

People with this problem People with this problem needneed dialysis, a treatment where a dialysis, a treatment where a machine does the job of the machine does the job of the kidneys. kidneys.

Through the Through the urinary systemurinary system:: Urine is released from theUrine is released from the body. body.

Through the Through the skinskin:: Sweat is released through Sweat is released through tinytiny openings in the skin called openings in the skin called porespores..