Intro

The excretory system is in charge of filtering the blood of waste and excess water. 99% of the blood filtered is rreabsorbed back into the blood. About 180 liters of blood are filtered each day. On average people only produce about 1-2 liters of urine a day. The excretory system includes the kidneys, ureters, bladder, and urethra.

Kidneys

The kidneys are where blood is filtered. They are composed of about 900,000 to 1 million nephrons for the average person. The kidneys have 3 parts: the renal cortex, the renal medulla and the renal pelvis. The renal cortex is the outermost part of the kidney which is incased in a membrane. The renal medulla is the inner part of the kidney. The renal pelvis is the base of the kidney where the ureters are attatched to.

Ureters

The ureters are small tubes wich carry urine from the kidneys to the bladder. They use peristalsis to move urine into the bladder just as the digestive system uses this method with food.

Bladder

The bladder is where urine is stored until it is expelled from the body. When the bladder is full it carries the urine out of the body through a small tube called the urethra.

Filtration Process

• Glomerus- The glomerus is a small ball of capillaries where the all possible waste is transferred from the capillaries to go into the Bowman's Capsule.

• Bowman's Capsule- Some reabsorbtion occurs and any healthy blood is returned into the capillaries. The waste is taken into the Proximal Tubule and into the Loop of Henle.

• Loop of Henle- At the Loop of Henle urea is condensed into urine and taken to the Distal Tubule. The Distal Tubule then takes the urine to the collecting duct.

• Collection Duct- The collecting duct takes the urine to the renal pelvis to go into the ureters.

Some Excretory Diseases

• ​Nephrosis- Causes swelling in arms, legs, face and lower abdomen. It also causes protein in urine, high cholesterol, foamy urine, slight weight loss and loss of apetite. It can be caused by genetic problems, immune disorders, kidney malfunction infections or membranous nephropanthy.

• Nephritis- An auto-immune disease that targets the glomeri of the nephrons in your kidneys. It causes swelling and irritation of the kineys. When lupus is involved in the disease it can be a severe disease. Possible symptoms are pain in the lower abdomen, blood in the urine or urine with a bad odor. It can be treated with antibiotics but with lupus steroids might be needed. 

• Kidney Stones- Kidney stones are small, solid deposits of calcium in the kidneys. They are caused by too much consumption of salt or other minerals. When having kidney stones you can experience severe pain in the lower abdomen, nausea, painful urination, fever chills or bloddy urine. For treatment you must take tons of fluids to try to pass the stones.