● Excretory System
We all obtain our nutrients from different sources which are later digested and metabolized in our body. After metabolic reactions, the body starts to sort out useful and toxic substances in an individual. As we all know, the accumulation of the toxins may be harmful and the body removes all the metabolic wastes by the process called excretion.
Different organisms follow different modes of excretion such as kidney, lungs, skin and eyes depending on their habitat and food habit.
For example- Aquatic animals excrete waste in the form of ammonia, while birds and insects excrete mainly uric acid. Humans produce urea as the major excretory product.
● Excretory System Organs
The human excretory system organs include:
•Kidney
•Ureters
•Urinary bladder
•Urethra
•Kidney
Kidneys are bean-shaped structures located on either side of the backbone and are protected by the ribs and muscles of the back. Each human adult kidney has a length of 10-12 cm, a width of 5-7 cm and weight around 120-170g.
The kidneys have an inner concave structure. The blood vessels, ureter and nerves enter the kidneys through the hilum, which is a notch at the inner concave surface of the kidney. The renal pelvis, a large funnel-shaped space is present inner to the hilum, is has many projections known as calyces.
•Ureter
A pair of thin muscular tubes called the ureter comes out of each kidney extending from the renal pelvis. It carries urine from the kidney to the urinary bladder.
•Urinary Bladder
It is a muscular sac-like structure, which stores urine. The urinary bladder is emptied by the process of micturition, i.e. the act of urination.
•Urethra
This tube arises from the urinary bladder and helps to expel urine out of the body. In males, it acts as the common route for sperms and urine. Its opening is guarded by sphincter muscles.
● Human Excretory System Diagram
The diagram below represents the different parts of the human excretory system.
[ Man or Atharv diagram bna le na ]
● Excretion in human
Excretion is the process where all the metabolic wastes are removed from the body. Excretion in humans is carried through different body parts and internal organs in a series of processes.
Diffusion is the most common process of excretion in lower organisms. A human body is an exceptional machine, where different life processes take place simultaneously. As a result, many waste products produced in our body are in various forms that include carbon dioxide, water, and nitrogenous products like urea, ammonia, and uric acid.
In addition to these, the chemicals and other toxic compounds from medications and hormonal products are also produced. Simple diffusion is not sufficient to eliminate these wastes from our body. We need more complex and specific processes in order to eliminate waste products.
Blood contains both useful and harmful substances. Hence, we have kidneys which separate useful substances by reabsorption and toxic substances by producing urine.
Kidney has a structural filtration unit called nephron where the blood is filtered. Each kidney contains a million nephrons.
Created by shyvom
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