Grade 10: Science - Part 02 - Human excretory system and excretory products

Grade 10: Science - Part 02 - Human excretory system and excretory products


Published on 5/12/2020



Kidneys can be cited as the primary organs of the urinary system and these organs filter the blood, eliminates the waste matter and excrete them in the form of urine. Kidneys are two bean shaped organs that are located just above the waist and on either side of the spine, opposite to each other. The right kidney is placed a bit lower than the left kidney in order to make room for the liver.  The external structure of the kidney is composed of the renal vein, renal artery and the ureter. The major role of the renal artery is to act as the main blood vessel which supplies blood to the kidney. The renal vein carries the blood away from the kidneys. The kidney has two main parts namely, the cortex and medulla. The renal cortex consists of a lot of blood capillaries and owing to this, it is dark in color. The renal medulla has renal pyramids whose tips are connected to the renal pelvis. The pelvis narrows and opens in to the ureter. The renal arteries carry blood that has excretory products to the kidneys and urine that is composed of water, salts, urea and uric acid is formed in the kidneys upon filtering the waste matter. The ureters carry the urine from the kidneys to the bladder. The urinary bladder temporally stores the urine and the urethra is the part which carries the urine from the bladder to the outside.

When the bladder is full, humans urinate through the urethra. 




We learnt that kidneys are the main organs that perform the function of the excretory system. Thus, the process of excretion gets disturbed when the kidneys are damaged.

Let us explore about some kidney diseases now.

  • Kidney stones - The mineral crystals that are composed of salts like calcium oxalate that get deposited in the kidneys are known as kidney stones. Sometimes these structures cause extreme pain and might be removed if they block the pathway. The kidney stones are formed due to the lack of sufficient water, regular intake of salty food and refraining from urinating when needed.
  • Kidney failure – This happens when the kidneys don’t function properly and start losing their ability to filter blood.  This happens gradually and high diabetes patients are vulnerable to this disease. A kidney transplant is the only cure for this and a process called dialysis is used to treat kidney failure. This can be caused as a result of the entry of toxic chemical substances or heavy metal in to the human body, smoking, intake of liquor, usage of drugs for a long period of time and suffering from diabetes for a long time.


  • Kidney infection -When the urethra is infected by micro-organisms such as bacteria the kidneys get infected and this may cause kidney damage if untreated. This is a urinary tract infection and can be life threatening too.

It is important to maintain healthy kidneys to make sure that the process of excretion takes place properly.

This can be done in several ways as follows. 

  • Regular and sufficient intake of clean water
  • Limit the consumption of extremely sour or salty food such as pickle
  • Refrain from smoking and taking liqour
  • Control blood sugar levels in the body as diabetic patients are vulnerable to kidney failure. 
  • If medicines are being taken regularly for a long period of time, take the exact dosage prescribed by the physician and get the kidneys tested on a regular basis to ensure that they function properly.
  • Keep the surrounding area of the urethra clean as it is prone to get infected.






by Mekhala Egodawele.

Photo source : Internet




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