Lymphatic System – Class 10

Lymphatic system for class 10

What is the Lymphatic System?

The lymphatic system is an essential part of the circulatory system of the human body. It plays a vital role in transporting a fluid called lymph from the body tissues into the blood vascular system.

Components of the Lymphatic System

What is Lymphatic System Class 10
Components of the Lymphatic System

The lymphatic system is made up of several components including:

  • Lymph
  • Lymph capillaries
  • Lymphatic vessels
  • Lymph nodes (or lymph glands)

Lymph

  • Lymph is a colourless, clear or slightly yellowish fluid that circulates throughout the lymphatic system. 
  • It is a fluid connective tissue similar to blood plasma but does not contain red blood cells. Lymph is formed from the interstitial fluid that surrounds the cells of the body. The interstitial fluid contains nutrients, oxygen and waste products that are exchanged between the cells and the blood capillaries.

Also Check – 15 Important Functions of Lymph

The lymph consists of two parts – 

  • Plasma
  • Lymphocyte cells.

Also Check – How Lymph is Formed ?

Plasma in the lymph

  • The plasma in the lymph is a fluid matrix similar in composition to blood plasma but containing less protein. 
  • It contains various substances that have been absorbed from the tissues, including digested fat, protein molecules, cellular waste products and microorganisms.

Also Check – Composition of the Lymph

Lymphocyte cells

Lymphocyte cells are a type of white blood cell found in the lymphatic system. They are responsible for recognising and fighting foreign substances such as bacteria, viruses and other pathogens. 

There are three types of lymphocytes-

  •  B cells
  • T cells 
  • Natural killer cells.

B cells produce antibodies that can neutralise or destroy certain pathogens. T cells can attack infected cells and cancer cells directly. Natural killer cells can recognise and kill infected cells and cancer cells without having to recognise specific antigens.

Lymphocyte cells are produced in the bone marrow and mature in the thymus gland and other lymphoid tissues. They circulate in the blood and lymphatic system and are constantly on the lookout for foreign substances to attack. When they encounter a foreign substance, they are activated and begin to multiply, creating a large number of cells that can recognise and attack the specific pathogen.

Also Check- Transportation In Human Beings

Why is Lymph called Extracellular Fluid?

Lymph is also called extracellular fluid because it flows around the cells and is outside the cells. It only flows in one direction, from the tissues to the heart, because backflow is prevented by valves in the large lymph vessels. Read More…

Lymph capillaries

  • Lymphatic capillaries are a network of thin-walled tubes with variable diameters and high permeability. 
  • They collect tissue fluid that drains from the interstitial spaces and are blind ended. 
  • The walls of lymphatic capillaries are made up of a single layer of endothelial cells that are loosely connected so that fluid and cells can easily move in and out of the capillaries.

Lymphatic vessels

  • Lymphatic vessels, also known as lymphatics, are formed from the connection of lymphatic capillaries. 
  • They are larger than lymph capillaries and are similar in appearance to veins. Non-return valves prevent the lymph fluid from flowing back. The lymph vessels eventually drain into the venous system, typically near the heart.
  • The lymphatic system does not have a pump like the circulatory system, so the movement of lymph fluid is facilitated by the contraction of smooth muscles in the walls of the lymphatic vessels and skeletal muscles during physical activity. 
  • As the lymph fluid moves through the vessels, it becomes slightly concentrated due to the loss of water as it moves through the system.

Lymph Nodes (or Glands)

  • Lymph nodes or lymph glands are small bean-shaped collections of reticular tissue located at intervals throughout the lymphatic system. 
  • They are encased in a fibrous capsule and are typically found in clusters in the neck, armpits, chest, abdomen and Groin.
  • The lymph nodes filter the lymph fluid and remove foreign particles such as bacteria and viruses. 
  • They also produce lymphocytes, a type of white blood cell that plays an important role in the body’s immune system. 
  • The lymphocytes in the lymph nodes produce antibodies that neutralise or eliminate harmful substances in the body and help activate other immune cells.

Also Check -Lymphatic System Diseases and Disorders

Functions of the Lymphatic System 

Drainage of Excess Tissue Fluid and Waste Products

The lymphatic system plays a crucial role in maintaining fluid balance between the blood and tissues. It collects excess interstitial fluid containing waste products and other substances and returns them to the bloodstream. This prevents the accumulation of fluid in the tissues and helps to maintain their function.

Transportation of Dietary Lipids from the digestive tract

The lymphatic system is responsible for transporting dietary lipids, such as fats and fat-soluble vitamins, from the small intestine into the bloodstream. These fats are absorbed by special structures called lacteals, which are a type of lymphatic vessel found in the lining of the small intestine. The lacteals transport the lipids into the lymphatic system, which eventually drains into the bloodstream.

Defence of the immune system through the production of antibodies and the elimination of foreign particles

The lymphatic system is an essential part of the body’s immune system. It contains lymphocytes, which are white blood cells responsible for recognising and fighting foreign substances such as bacteria, viruses and cancer cells. The lymphocytes produce antibodies, i.e. proteins that neutralise or eliminate harmful substances in the body. The lymph nodes also act as filters , removing foreign particles and pathogens from the lymph fluid before it re-enters the bloodstream.

Regulating the volume and composition of tissue fluid

The lymphatic system helps regulate the volume and composition of tissue fluid. It collects excess interstitial fluid and returns it to the bloodstream, which helps maintain fluid balance between blood and tissue. The lymphatic system also removes waste products and other substances from the interstitial fluid, which helps to maintain the correct composition of the tissue fluid.

Maintenance of blood volume and Pressure

The lymphatic system plays a role in maintaining blood volume and blood pressure. It traps excess interstitial fluid, helping to prevent a drop in blood volume and blood pressure. The lymphatic system also returns proteins and other substances that have leaked out of the blood vessels back into the bloodstream, helping to maintain the proper balance of substances in the blood.

Also Check – 9 Important function of Lymphatic System

Frequently asked Questions on Lymphatic System 

What is the lymphatic system, and what is its function?

Answer –  The lymphatic system is a vital part of the circulatory system that transports a fluid called lymph from the body tissues into the blood vascular system.

What are the components of the lymphatic system?

Answer – The components of the lymphatic system include lymph, lymph capillaries, lymphatic vessels, and lymph nodes (or lymph glands).

What is lymph, and how is it formed?

Answer –  Lymph is a colorless, clear, or slightly yellowish fluid that circulates throughout the lymphatic system. It is formed from the interstitial fluid that surrounds the cells of the body and contains nutrients, oxygen, and waste products exchanged between the cells and the blood capillaries.

Also Check – What are the components of the transport system in Human Beings? What are the functions of these components?

What are the two components of lymph, and what do they contain?

Answer –  The two components of lymph are plasma and lymphocyte cells. The plasma in lymph is a fluid matrix that contains various substances, including digested fat, protein molecules, cellular waste products, and microorganisms. Lymphocyte cells are a type of white blood cell found in the lymphatic system that recognize and fight foreign substances such as bacteria, viruses, and other pathogens.

What are the three types of lymphocytes, and what are their functions?

Answer –  The three types of lymphocytes are B cells, T cells, and natural killer cells. B cells produce antibodies that can neutralize or destroy certain pathogens. T cells can attack infected cells and cancer cells directly, while natural killer cells can recognize and kill infected cells and cancer cells without having to recognize specific antigens.

Also Check – Human Circulatory System

Where are lymphocyte cells produced and mature?

Answer –  Lymphocyte cells are produced in the bone marrow and mature in the thymus gland and other lymphoid tissues.

How do lymphocytes circulate in the body, and what happens when they encounter a foreign substance?

Answer –  Lymphocytes circulate in the blood and lymphatic system and are constantly on the lookout for foreign substances to attack. When they encounter a foreign substance, they are activated and begin to multiply, creating a large number of cells that can recognize and attack the specific pathogen.

Why is lymph called extracellular fluid?

Answer –  Lymph is called extracellular fluid because it flows around the cells and is outside the cells. It only flows in one direction, from the tissues to the heart, because backflow is prevented by valves in the large lymph vessels.

What are lymph capillaries?

Answer – Lymph capillaries are a network of thin-walled tubes with variable diameters and high permeability that collect tissue fluid that drains from the interstitial spaces and are blind ended.

How are lymphatic capillaries constructed?

Answer – The walls of lymphatic capillaries are made up of a single layer of endothelial cells that are loosely connected so that fluid and cells can easily move in and out of the capillaries.

What are lymphatic vessels?

Answer – Lymphatic vessels, also known as lymphatics, are formed from the connection of lymphatic capillaries. They are larger than lymph capillaries and are similar in appearance to veins. Non-return valves prevent the lymph fluid from flowing back. The lymph vessels eventually drain into the venous system, typically near the heart.

How is lymph fluid moved through the lymphatic vessels?

Answer – The movement of lymph fluid is facilitated by the contraction of smooth muscles in the walls of the lymphatic vessels and skeletal muscles during physical activity.

What are lymph nodes or lymph glands?

Answer – Lymph nodes or lymph glands are small bean-shaped collections of reticular tissue located at intervals throughout the lymphatic system. They filter the lymph fluid and remove foreign particles such as bacteria and viruses. They also produce lymphocytes, a type of white blood cell that plays an important role in the body’s immune system.

What are the functions of the lymphatic system?

Answer – The lymphatic system plays a crucial role in maintaining fluid balance between the blood and tissues, transportation of dietary lipids from the digestive tract, defence of the immune system through the production of antibodies and the elimination of foreign particles, regulating the volume and composition of tissue fluid, and maintenance of blood volume and pressure.

How does the lymphatic system maintain fluid balance between the blood and tissues?

Answer – The lymphatic system collects excess interstitial fluid containing waste products and other substances and returns them to the bloodstream, preventing the accumulation of fluid in the tissues and helping to maintain their function.

How does the lymphatic system transport dietary lipids from the digestive tract?

Answer – The lymphatic system is responsible for transporting dietary lipids, such as fats and fat-soluble vitamins, from the small intestine into the bloodstream. These fats are absorbed by special structures called lacteals, which are a type of lymphatic vessel found in the lining of the small intestine.

How does the lymphatic system defend the immune system?

Answer – The lymphatic system contains lymphocytes, which are white blood cells responsible for recognising and fighting foreign substances such as bacteria, viruses and cancer cells. The lymphocytes produce antibodies, i.e. proteins that neutralise or eliminate harmful substances in the body. The lymph nodes also act as filters, removing foreign particles and pathogens from the lymph fluid before it re-enters the bloodstream.

How does the lymphatic system help regulate the volume and composition of tissue fluid?

Answer – The lymphatic system helps regulate the volume and composition of tissue fluid by collecting excess interstitial fluid and returning it to the bloodstream, which helps maintain fluid balance between blood and tissue. The lymphatic system also removes waste products and other substances from the interstitial fluid, which helps to maintain the correct composition of the tissue fluid.

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