Human Excretory System
The Excretory System is the biological system responsible for removing metabolic waste products from the body. In humans, the main waste product is urea (nitrogenous waste), which is removed from the blood by the kidneys.
Note: Covered under Class 10 Science (Chapter 6: Life Processes) NCERT Syllabus.
Anatomy of Excretory System
The human excretory system consists of:
- Kidneys (2): Bean-shaped organs located in the abdomen that filter blood.
- Ureters (2): Tubes that carry urine from the kidneys to the urinary bladder.
- Urinary Bladder (1): A muscular sac that stores urine.
- Urethra (1): A tube through which urine is released from the body.
Fig 1: Human Excretory System.
The Nephron: Filtration Unit
Each kidney contains millions of filtration units called Nephrons. A nephron has two main parts:
- Bowman’s Capsule: A cup-shaped end that contains a cluster of capillaries called the Glomerulus. This is where filtration happens.
- Tubular Part: Where reabsorption of useful substances (glucose, amino acids, salts, water) takes place.
Mechanism of Urine Formation
| Step | Description |
|---|---|
| 1. Filtration | Blood is filtered in the Glomerulus under high pressure. Waste and small molecules pass through. |
| 2. Reabsorption | Useful substances like glucose, amino acids, and water are reabsorbed back into the blood in the tubular part. |
| 3. Secretion | Excess salts and waste remain in the tubule and form urine. |
Artificial Kidney (Hemodialysis):
In case of kidney failure, an artificial device is used to remove nitrogenous waste products from the blood through dialysis.
In case of kidney failure, an artificial device is used to remove nitrogenous waste products from the blood through dialysis.
Chapter Assessment
1. What is the functional unit of the kidney?
The functional unit of the kidney is the Nephron.
2. Name the major nitrogenous waste removed by kidneys.
Urea is the main nitrogenous waste product removed from the blood by the kidneys.
Reference: NCERT Class 10 Science.
Reviewed under Sarkari Service Prep Academic Policy.
Reviewed under Sarkari Service Prep Academic Policy.
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