AP Biology 2008-2009

Excretory System38-3

AP Biology2008-2009

Functions of the Excretory System

Regents Biology

What liquid waste do we make?

Digesting protein makes poison nitrogen waste = ammonia = poison

H

CO2 + H2O

NH2 = ammonia

H

HN C—OH

|| O

H|

—C—|

2008-2009

Regents Biology

Nitrogen waste disposal in water Ammonia

2008-2009

Regents Biology

Nitrogen waste disposal on land Land animals

need to save H2O evolved less poisonous waste

product urea

excrete urea & H2O as urine

2008-2009

Regents Biology

Nitrogen waste disposal in egg Egg-laying land animals

no place to get rid of waste while in egg needs waste that doesn’t dissolve in water

inside egg uric acid stays a powder, doesn’t dissolve in water

birds, reptiles, insects

2008-2009

Regents Biology

Uric acid adults excrete white paste

not liquid waste white bird poop is

really their pee!

Getting a little personal,

aren’t we!

2008-20092008-2009

Regents Biology

transport proteins Waste urea leaves cell by diffusion

How do animal cells regulate their contents?

O2

sugar

sugar nutrients

CO2

urea

nutrients

O2

Regents Biology

Organs of the Urinary System The main organs of the

urinary system are two bean-shaped kidneys.

The kidneys filter blood that contains wastes collected from cells.

It is made up of about 1 million tiny filtering units called nephrons (NEF rahnz).

2008-2009

Regents Biology

Human kidney Mammals have a pair of

bean-shaped kidneys Blood is supplied by a renal artery leaves by a renal vein

Regents Biology

In approximately 5 min, all of the blood in your body passes through the kidneys

Approx. 2,000 L of blood is filtered daily by the kidneys.

Filtration in the Kidney

2008-2009

Regents Biology

Bladder

2008-2009

Regents Biology

Nephron = Kidney’s filter Blood enters the nephrons. Cells and proteins stay in the

blood Water, sugar, salt and wastes

in the blood enter the tubules in a cuplike structure in the nephron.

Its called “filtrate” Capillaries reabsorb most of

the water, sugar, and salt. Becomes urine

to bladder

Regents Biology

Urine Urine exits the kidneys into ureters. Urine flows from ureters to the bladder. Urine flows from

the bladder through the urethra and out of the body.

2008-2009

Regents Biology

Dialysis

A person who has only one kidney still can live normally.

The remaining kidney increases in size and works harder to make up for the loss of the other kidney.

If both kidneys fail, the person will need to have his or her flood filtered by an artificial kidney machine in a process called dialysis (di AH luh sus).

2008-2009