Excretory Products and Their Elimination

The excretory system is a component that helps to maintain homeostasis or a stable internal environment without which it would be impossible to survive. Commonly referred to as excretion, it involves the removal of metabolic waste products from the body to maintain homeostasis. In this chapter, students learn the different aspects and their modes of elimination of excretory products and the human excretory system, types of wastes and the respective organs involved in excretion. This section fits well within Biology and is important for exams like NEET, JEE and more.

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This Story also Contains

1. What do mean by Excretory Products and Their Elimination?
2. What Are Excretory Products?
3. Excretory Systems among Different Organisms
4. The Human Excretory System
5. Structure and Functions of Kidneys
6. Other Excretory Organs in Humans
7. Diseases of the Excretory System
8. Comparison of Excretory Products
9. Role of Excretory System in Osmoregulation
10. Tips, Tricks, and Strategies to Prepare For Excretory Products and Their Elimination
11. Weightage of Topics in Different Entrance Exams
12. Types of Questions Asked on the Topic in Different Exams
13. Recommended videos on "Excretory Products and Their Elimination"

What do mean by Excretory Products and Their Elimination?

The term excretory products and their elimination refers to the biological processes of elimination whereby organisms remove waste coming from metabolic activities. This vital function prevents the accumulation of toxic substances that might act interferently to cellular processes and wellness. The excretory system regulates the amount and concentration of body fluids, eliminates metabolic wastes, and also helps maintain the correct pH level.

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• Body Fluids And Circulation
  

What Are Excretory Products?

Excretory products can be categorized broadly into two:

Metabolic Waste Products:

• Urea: It is produced by the combination of ammonia in the liver; less toxic to the system than ammonia.

• Uric Acid: It is a waste product produced due to nucleotide deamination; less soluble in water.

• Ammonia: This is highly toxic and a waste product of protein breakdown; the excretory of most aquatic animals.

• Carbon Dioxide: Breathed out as a product of cellular respiration.

• Water: Lost through urination, sweat, and respiration.

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Non-Metabolic Waste Products

• Bile Pigments: A product of the breakdown of haemoglobin.

• Excess Salts: Eliminated to maintain the electrolytes within normal ranges.

Excretory Systems among Different Organisms

Diverse organisms have different excretory systems based on their habitat and lifestyle:

Single-celled Organisms:

• Protozoa: Contain a contractile vacuole that gets rid of waste products.

• Hydra: Uses diffusion for waste removal.

Invertebrates

• Earthworms: Use nephridia for removing waste.

• Insects: Mollusks have Malpighian tubules with which they secrete waste.

Vertebrates:

• Fish: The system relies on gills and kidneys to excrete the waste products.

• Amphibians: The system depends on the skin and kidneys.

• Reptiles and Birds: Primarily utilizes the kidneys and cloaca.

• Mammals: The system uses the kidneys that extract the waste products from the body.

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• NCERT solutions for class 11 Mathematics.

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The Human Excretory System

The human excretory system consists of several organs that work together to remove the waste products from the human body:

Parts:

• Kidneys: The system filters blood and comes out as urine.

• Ureters: The system removes urine from the kidneys to the bladder.

• Urinary Bladder: The system holds urine in the bladder until it is expelled from the body through excretion.

• Urethra: The tube through which urine comes out of the body.

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Structure and Functions of Kidneys

The two prominent units of the kidneys are the cortex and medulla.

The nephron is the secretory unit that forms urine in three consecutive steps:

• Glomerular Filtration
• Tubular Reabsorption
• Tubular Secretion

Hormones that Control Urinary Secretion

• ADH (Anti-diuretic hormone): It regulates water reabsorption in the kidneys.

• Aldosterone: It influences sodium reabsorption.

Other Excretory Organs in Humans

Besides kidneys, human beings have many other organs that help in excretion:

• Skin: Sweat glands remove water, salts, and minute amounts of urea.

• Lungs: Release carbon dioxide and water vapour during respiration.

• Liver: Convert ammonia to urea and break down haemoglobin to form bile pigments.

Diseases of the Excretory System

The excretory system can be affected by a range of diseases:

• Kidney stones: Concentrated minerals that cause pain and blockage.

• Urinary tract infection (UTI): Bacterial infection of the urinary system.

• Glomerulonephritis: Inflammation of the kidney glomeruli.

• Chronic kidney disease (CKD): Slow progression of kidney function loss.

Comparison of Excretory Products

Nitrogenous wastes from different organisms vary with habitat:

• Ammonotelic Organisms: Excret ammonia (most aquatic animals).

• Ureotelic Organisms: Excrete urea (mammals and amphibians).

• Uricotelic Organisms: Excret uric acid (birds and reptiles).

• This adaptation conserves water while detoxifying waste effectively.

Role of Excretory System in Osmoregulation

Osmoregulation is the maintenance of water and electrolyte balance in an animal's body. The excretory system maintains:

• Proper salt-water balance

• Adaptations from simple diffusion in unicellular organisms to the most complex systems in vertebrates

• Surviving both in freshwater and terrestrial habitats

Tips, Tricks, and Strategies to Prepare For Excretory Products and Their Elimination

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Weightage of Topics in Different Entrance Exams

Understanding the weightage of topics can help prioritize your study efforts in Excretory Products and Their Elimination for various entrance exams.

Types of Questions Asked on the Topic in Different Exams

Familiarizing yourself with the types of questions related to Excretory Products and Their Elimination can improve your exam performance.

Use this structured approach to help you prepare effectively for the chapter on Excretory Products and Their Elimination in your biology curriculum. With mnemonics, visual aids, and practice questions, critical concepts will be better understood and retained.

One of the most critical concepts that the student aspirant to a career in biology needs to know is that of excretory products and their elimination, especially those taking NEET exams. Such knowledge not only keeps one learning but also makes one more conscious of the functions occurring within the body.

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