Overview of the Urinary System: Urine colors and possible Causes - HHM

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Sunday, 20 December 2015

Overview of the Urinary System: Urine colors and possible Causes

What is the Urinary System?

Colors of urine and Meaning

The Urinary system is the body’s excretory(drainage) system that takes care of producing, storing and removing waste products of metabolism out of the body as URINE. It is also called the Renal System.

What makes up the Urinary System?

Network of the urine system


A two bean shaped organs located below the rib cage. Its functional unit is the Nephrons that help in producing the urine. The kidney is the major organ that keeps the ionic and electrolyte balance in the body. It maintains the body’s pH, secrete hormones, excrete waste and toxins. It is the organ associated with HOMEOSTASIS (metabolic equilibrium).


The ureters carry urine from the kidney, one from each side to the Bladder.


A balloon shaped organ located between the pelvic. It is a site where urine is collected and stored until urination. It act as a reservoir and can store urine upto 2 cups and expel when the individual is ready for urination. The passage of urine is controlled by the mucles in the wall while the sphincter of the bladder is controlled by the brain.


The urine from the bladder is passed out of the body through the Urethra. It is connected to the external urinary organ.

How does the Urinary System Works?

The urine is produced in the kidney and transported by two tubes (Ureters) to be stored temporary in the Bladder. During urination the urine leaves the bladder through the Urethra and is excreted out of the body.

What affects the amount of urine a person produces?

The quantity of urine production in adult humans is around 0.6-2.6 Litres daily. The quantity of urine produced and excreted by an individual varies depending on any of the following;
  • The Amount of Liquid and food consumed
  • Amount of fluid lost through sweat and breathing
  • The age of the individual; Children produces less urine
  • Certain disorder. 

Composition of Urine

Urine is an aqueous solution of about 91-96% of water, with decreasing concentration in Urea, chlorine, sodium, potassium, Creatinine and other dissolved ions, and inorganic and organic compounds. Abnormal composition of urine indicates a disease condition.
The pH of urine is approximately 6.2.

What causes the color of Urine?

The color of urine ranges from  pale yellow to colorless but usually amber. Its appearance depends on the level of hydration. The color of healthy humans comes from the presence of Urobilin. The color of urine can be affected by drugs, diseases, the food consumed and the physiology of the body etc. below are colors of urine and its indication;
  • Colorless – over-hydration
  • Dark yellow – dehydration
  • Yellow/light orange – release of B Vitamins and other nitrogen containing biomolecules (deamination)
  • Orange – caused by some drugs
  • Blood in urine – hematuria
  • Dark orange/brown – symptoms of jaundice, rhabdomyolysis, or Gilbert’s syndrome
  • Black/dark colored – melanuria
  • Pinkish urine – consumption of beets
  • Green – consumption of asparagus / green dyes
  • Reddish/brown – porphyria
  • Blue – consumption of blue dyes
  • Purple – purple urine bag syndrome

Function of the Urinary System

It filters blood and keeps it free from;
-          Metabolic wastes
-          Excess water
-          Excess ions
Dispose of nitrogenous waste from the blood
-          Urea
-          Uric acid
-          Creatinine
Regulate the balance of water and electrolytes (like potassium and phosphate), acids and bases.
It secrets hormones that helps in regulating Blood pressure.

The African notion that malaria is the cause of a yellow urine color might in some cases be true because during the invasion of body tissues and cells by the plasmodium parasite, the body immune system is triggered which causes the release of proteins or antibodies. When these proteins are broken down, the end product is a nitrogen remnant which on release through the urine imparts a yellow color to the urine of such patient.