Human Excretory System


 
 
Concept Explanation
 

Human Excretory System

Excretory System in Man: Our excretory system consists of kidneys, blood vessels that join them, ureters, urinary bladder and urethra. They help produce and excrete urine. The main part of urinary system are:

  • Kidney:  These are two bean-shaped purplish brown coloured structures located in the back of the abdominal cavity.It is the main organ of excretion through which the nitrogenous wastes are eliminated in the form of urine, about 12 cm long, about 6 cm thick and weighs about 150gm. Kidneys contain millions of nephrons which filter 170 to 200 litres blood to produce 1-1.8 litrs of urine daily.
  • Renal Arteries:  Two  renal arteries constantly transport blood to each of the kidney.
  • Renal vein : Two renal veins return useful nutrients back into the blood stream after filtering the unwanted materials in kidneys.
  • Ureters: Two tubes which arise from each kidney and carry urine tio the bladder.
  • Urinary bladder: This isa muscular sac -like structure where urine is stored till it is thrown out.
  • Urethra:  This is a short muscular tube that carries urine from  the urinary bladder to the outside oft he body.
  • A volume of blood nearly equivalent to that in the whole body passes through the kidneys every four or five minutes. The kidneys produce urine to filter out the waste products, like urea and uric acid, from the blood. Urine leaves each kidney through a tube called ureter. The ureters from both the kidneys are connected to the urinary bladder that collects and stores urine. Ureters carry urine from the kidneys into the urinary bladder. The urethra is a canal that carries urine from the bladder and expels it outside the body.

     
     


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