Cells & Systems The Excretory System

What does it do? Our body produces a bunch of different waste products If they were to build up we could get seriously sick or worse excretory systemEnter the excretory system! –The system responsible for waste removal

Waste Products Example we’ve covered already… What waste product do we breath out? –CO 2 Digestive system breaks down protein we are left with ammonia –This is very toxic! I am ammonia!! Ummkay? Noooo!! Help!!

Waste Products Cont … We also have processes that create … –Excess water –Excess salt –Solid waste (poop) –Etc … So how do we break them down and get rid of them? GROSS!!!! I’m Britney Spears. I don’t understand science. Don’t ask me!

The Organs The Liver –Main role is the digestive system Enzyme release, filter, etc … –In the excretory system it takes the toxic ammonia out of the blood stream urea –Converts the ammonia to a substance called urea –Puts the less harmful urea back into the bloodstream

The Organs

The Organs Cont … The Kidneys –A filter site for the body –Approx 10cm long & you have 2 –Filter blood of unwanted/unneeded Urea Water Salts –They produce urine (pee!)

The Organs Cont …

Interesting kidney facts … –Every drop of blood in your body on a given day is filtered about 300 times –This means about 180L of blood passes through kidneys each day –On average you produce 1.5L of urine per day Why do we filter so much?

How do I make pee? 1) Blood enters kidney via renal artery 2) Artery branches to smaller & smaller vessels nephrons3) Now in capillaries they enter the filter units called nephrons! We have millions of them 4) Nephrons remove waste & produce urine 5) Clean blood goes back into system via renal vein ureter6) Waste (urine) goes down ureter

How do I make pee?

Ureters & Bladder & Urethra UretersUreters are long tubes –Connect kidneys to bladder bladderThe bladder is sac covered in muscle tissue Urine enters bladder it expands –Can hold 1L of urine The muscles contract and push the urine out through the urethra

Ureters & Bladder & Urethra

The Skin Has anyone ever tasted their sweat? –What does it taste like? Below the surface of your skin there are 1000s of tiny sweat glands What does sweat do? –Keeps you cool –Removes excess salt

The Power of Urine Urine can tell you if you have certain diseases –Diseases that for example affect how the kidneys function Could have protein in urine because filtration is not happening correctly Glucose in the urine if you have diabetes The Power of the Nose

Dialysis If your kidneys do not work properly medicine has invented a machine to do the work for you Dialysis Machine It can remove the waste from the blood just as your kidney would So how does it work?

Dialysis Cont… During dialysis –Your blood enters a special tubing inside the machine –The tubing is selectively permeable –The tube is surrounded by fluid –Waste diffuses out of the blood into the fluid while certain substances diffuse back into the blood from the fluid –Clean blood pumped back into patient –Can take 4-6 hours to fully clean the blood

Cells & Systems 4 Down – 1 More To Go!