The body is self-sufficient.
The lungs, skin and intestines discharge gases, sweat and stools.
The urinary system cleans the blood and regulates the amount of water in the body.
Put your hand on the bottom ribs, go around them along the back, your kidney is there, protected by the ribs at the bottom.
Each kidney is about 12cm high by 7cm wide, like a potato or a computer mouse!
The kidneys are so important that you have two!
But if something were to happen to one, you could stay healthy, only with the other.
That is why giving a kidney to a sick person is possible.
By using food and oxygen to make the energy you need, the cells produce waste that has to be disposed of.
By accumulating they would poison the body.
The kidneys clean the blood and remove excess water.
They filter the blood before returning it to the circulation.
Waste such as urea is evacuated!
The urine is, so to speak, clean...in a certain way!
It is sterile, ie without microbes, and contains 95% water and 5% urea.
It smells bad if it stagnates and collectsbacteria.
After a while, the urea turns into ammonia,and takes that smell...very special!
Thus, the color of your urine is an indicator
Of your state of health, if it is pale yellow or clear, everything is normal;
If it is dark yellow, it is because you are a little dehydrated and you need water, if it is troubled, it is because you may have an infection!
Both kidneys are surrounded by a mass of adipose tissue called adipose capsule.
Each kidney is about 11.25cm long and 5 to 7.5cm wide.
Its thickness is generally greater than or equal to 2.5 cm.
The kidneys are composed of an external cortex of lighter color;
of an inner medullary, of darker color, in which are the renal pyramids, or Malpighi pyramid, and a funnel-shaped structure called Bassinet.
The renal pyramids are a series of conical elements located within the medulla of the kidneys.
The bulk of the
Renal pyramids is composed of nephrons,structures dedicated to the filtration of the blood and to the creation of urine in the urinary system.
Here's how it works...
Areas of cortical tissue insinuate between the renal pyramids.
They are called the renal columns, or columns of Bertin.
The color and texture of renal columns and renal pyramids make them easily identifiable in a kidney section.
The pyramids shrink into papillae(tips) as they converge towards the pelvis.
The urine from the pyramid nephrons is conveyed from the pyramids to the pelvis and then into the ureters.
It is then collected in the bladder and then evacuated by the urethra.
Both kidneys have more than one million microscopic tubes called nephrons.
The blood that comes from the heart loaded with waste comes at the beginning of the nephrons.
There, it is found in tiny vessels which form a sort of small ball, the glomerulus.
It leaves the vessels and passes into the urine.
Further, the useful elements(water, sugar, salt) are reabsorbed and return to the bloodstream.
The rest of the urine, with urea and excesswater, continues to a tube called ureter and is found in the bladder.
The collecting tubes are located in the pyramids.
Each of them receives the distal circumferential tubes of 11 nephrons on average.
They descend rectilinearly into the rénal medulla, increasing gradually in diameter.
In the internal medulla, they merge in groups of eight to form a papillary canal.
The wall of the collecting tube is made of simple and prismatic epithelium.
These cells may have a light or dark appearance.
The clear or principal cells are the most numerous, and the dark or intercalated cells are absent from the lower parts of the tube.
The Bassinet is a funnel-shaped structure that originates in the kidney and then protrudes from the kidney to join the ureter.
As a component of the urinary system, the
Bassinet acts as an excretory channel for the kidney, conveying urine from the kidneys to the ureters.
The upper part of the pelvis is in the central cavity of the kidney, the renalsinus
The lower part of the pelvis protrudes from the kidney, then shrinks where it joins the ureter.
The urine leaves the kidneys by the pelvis, passes through the ureters,and is collected in the bladder and finally discharged by the urethra.
The bladder is an expansible bag containing about four cups of liquid.
A sphincter is a muscle that tightens like a ring to close a tube.
There is a sphincter at the base of each ureter
To prevent the urine from rising.
There is another sphincter down at the base of the bladder so that the urine does not flow out.
When the bladder is full, small nerves in its wall are stimulated!
They send to the brain the information: "it's time to urinate!"