Excretion is the elimination of waste substances

Urine: 95% water 5% waste/yellow coloured- urea

Sweat: 99% water

Kidneys:

 Renal vein(blue)/renal artery(red)

Cortex\renal pelvis\medulla\ureters \ bladder\urethra

Function: filtration/reabsorbed/excret

Blood: 45% blood cell/ 55% blood plasma

Cells in blood/mm³: white(8000), platelets(250000), red (+5million)

Red: oxygen

Platelets: help stop bledding

White: protect the body from infection

Blood vessels:

Arteries (thick/stronger walls) high pressure, blood goes to...

Veins: thinner , low pressure, from organs to heart

Capillares: thinner(connect)

Heart:

Myocardium.             Atria 1

       Atria2.             

                               Ventricle 1

    Ventricle 2 

Heartbeat

1atrial contractiin (systole) atriash-ventricles

2 ventricular contraction (systole)ventricles-out

3 diastole (relaxation)out-ralaxation

Lungs:

Medium - aorta

Parts: veins (left(vena cavae) and right(pulmonary artery))

Flow of blood:

Blood exits the heart from right ventricle and travels to lungs trough pulmonary arteries.

Gas exchange→ blood picks up O² and releases CO²

The blood returns to the pulmonary veins, entering the heart at the left atrium.