Excretion and Excretory Products 

What is Excretion?

The biology process of eliminating metabolic wastes and toxic substances from our body cells is called  excretion. This type of removing wastes are found in both plants and animals. 

What are  Excretory Products?

The excretory products differ between plants, animals, humans and other living species. The primary excretory products include amino acids, ammonia, carbon dioxide,  urea, uric acid and water. Among these excretory products ammonia is the primary excretory product, which is mainly derived from the proteins present in the food we eat. 


Similar to humans, plants do not possess their excretory organs. This is mainly because the main excretory products produced by plants are carbon dioxide, water vapour and oxygen, which can be easily eliminated by the specialized cells. Stomata in plants play a vital role in gaseous exchange, maintain the moisture balance in the plant cells  and also function by removing excess amounts of water molecules in the form of water vapour. This biological process is called transpiration.

All animals, birds, reptiles and other insects do differ in their excretion process and excretory products. 


For instance:

  • All  reptiles, birds, and insects excrete nitrogenous wastes as uric acid
  • All aquatic animals, earthworms, spiders, some rare species of reptiles and  birds excrete ammonia.

Why Excretion is required in humans and other living organisms?


Excretion is observed in every living organism from a small insect to a huge mammal. The mode of excretion usually differs between living organisms and is one among the most  important life processes. 


All living organisms existing on this planet earth excrete metabolic wastes, excess of water and other toxic substances produced by the different cellular processes. These products need to be removed or eliminated out the living system as they are toxic, which might get mixed up with the blood cells, which causes harm to cells, tissues, organs and finally to enrite the body which results i\in death caused by the accumulation of toxic wastes.

Human Excretory System

We humans have a well developed excretory system, which functions by removing toxic wastes and helps by maintaining homeostasis.

The excretory system organs  comprises a pair of kidneys, ureters, urinary bladder and a urethra. 


Let have a quick glance at the main excretory organs



  • Kidneys


A pair of kidneys, located on the left and right side of the spine, near the liver functions as the primary excretory organs in humans.



  • Ureters


A thin tube like structure coming out of each kidney is Ureters. A pair of Ureters in the human excretory system functions by carrying urine from the kidney to the  urinary bladder. 



  • Urinary Bladder


A hollow, muscular and sac-like structure present on the pelvic floor is called urinary bladder.It is primarily involved in the process of micturition, storage of urine until micturition and also protects expelling urine from the body.



  • Urethra


A  tube-like structure, extending out from the urinary bladder is called urethra. It helps in releasing urine outside the body. Compared to females, males have longer and thicker urethra. In males, urethra is primarily involved in both urinating and ejaculating.


This concludes the information related to excretion and excretory products . Stay tuned with BYJU’S to learn more in detail about the excretory system in different species. Students can also enjoy learning by watching interactive youtube videos on various topics by subscribing to our Youtube channel.