The dual function of excretory systems is the elimination of the waste products of metabolism and to drain the body of used up and broken down components in a liquid and gaseous state.
The kidneys are large, bean-shaped organs which are present on each side of the vertebral column in the abdominal cavity.
The kidneys remove from the blood the nitrogenous wastes such as urea, as well as salts and excess water, and excrete them in the form of urine.
In humans, the ureters arise from the renal pelvis on the medial aspect of each kidney before descending towards the bladder on the front of the psoas major muscle.
The urethra is a tube which transports urine from the urinary bladder to the outside of the body through the penis or vulval vestibule.
One of the main functions of the lungs is to diffuse gaseous wastes, such as carbon dioxide, from the bloodstream as a normal part of respiration.
The typical brown colour of mammal waste is due to bilirubin, a breakdown product of normal heme catabolism.
[1] The lower part of the large intestine also extracts any remaining usable water and then removes solid waste.
For example, the liver transforms ammonia (which is poisonous) into urea in fish, amphibians and mammals, and into uric acid in birds and reptiles.
Invertebrates lack a liver, but most terrestrial groups, like insects, possesses a number of blind guts that serve the similar functions.
The moist, scale-less skin is therefore essential in helping to rid the blood of carbon dioxide, and also allows for urea to be expelled through diffusion when submerged.
That is particularly true for acoelomate groups like cnidarians, flatworms and nemerteans, who have no body cavities and hence no body fluid that can be drained or purified by nephrons, which is the reason acoelomate animals are thread-like (nemertans), flat (flatworms) or only consist of a thin layer of cells around a gelatinous non-cellular interior (cnidarians).
[citation needed] Secretions of sweat from the eccrine glands play a large role in controlling the body temperature of humans.
The two functions consist of secretion of a filtrate in response to acetylcholine and reabsorption of sodium near the duct when there is water in excess so that a sweat can be surfacing the skin.
Bile salts can be considered waste that is useful for the body given that they have a role in fat absorption from the stomach.
When they do not dissolve correctly and further build up, they will commonly lodge themselves in the urinary tract and in this case, are usually small enough to pass through urine.
In extreme situations, however, these stones may lodge themselves within the tube that connects the kidney and the bladder, called the ureter.
In this case, they become very large in size and will most likely cause great pain, bleeding, and possibly even block the flow of urine.
Most of these treatments involving kidney stone removal are done by a urologist; a physician who specializes in the organs of the urinary system.
Larger, more serious cases may demand Cystoscopy, Ureteroscopy, or Percutaneous Nephrolithotomy, in which the doctor will use a viewing tool or camera to locate the stone, and based on the size or situation, may either chose to continue with surgical removal, or use the shock wave lithotripsy treatment.
Once the kidney stone(s) are successfully eliminated, the urologist will commonly suggest medication to prevent future recurrences.
Treatment for acute pyelonephritis is provided via antibiotics and an extensive urological investigation is conducted to find any abnormalities and prevent recurrence.
[13] In chronic pyelonephritis, patients experience persistent abdominal and flank pain, high fever, decreased appetite, weight loss, urinary tract symptoms and blood in the urine.
Chronic pyelonephritis can also lead to scarring of the renal parenchyma caused by recurrent kidney infections.