Execratory System (Prepared by: (Sarah AlSaif, Ghadah AlSedairy, Reema…
Filteration and Excretion
Bean-shaped organ that is the most important in the Excretory system.
filter out wastes, water, and salts from the blood
Each kidney contains approximately one million filtering units called nephron
how nephron filters the blood?
Blood enters each nephron through a long tube that is surrounded by a ball of capillaries called the glomerulus (is surrounded by a structure called the Bowman’s capsule.)
The renal artery transports nutrients and wastes to the kidney and branches into smaller and smaller blood vessels
nutrients and waste will reach the tiny capillaries in the glomerulus
The walls of the capillaries are very thin, and the blood is under great pressure
As a result, nitrogenous waste product (water and substances dissolved in the water) called urea, are pushed through the capillary walls into the Bowman’s capsule
Larger molecules, such as red blood cells and proteins, remain in the bloodstream.
reabsorption and formation of urine
Much of the lost water and useful substances, such as glucose and minerals, are reabsorbed into the capillaries surrounding the renal tubule.