Differentiate Between Blood and Lymph: CBSE Class 10 Biology Notes

Understanding the most vital biology concepts at the class 10 level ensures a stronger base for students who plan to pursue medical science. The difference between blood and lymph is one of those basic concepts. However, it is important to understand the composition and functions of blood and lymph to acknowledge the differences between the two completely.

On reviewing Class 10 Previous Year Question Papers, one can note that differences, similarities, definitions, functions, and reasons constitute a larger part of the biology exam questions. The following article compares the two fluids and also provides definitions and functions. 

What is Blood?

Definition: The constantly circulating, specialised body fluid in the circulatory system of vertebrates that delivers oxygen and nutrients to various body cells and carries away metabolic waste products from them is called blood.

It is a fluid connective tissue in our body and contributes significantly to the transportation of several substances from one part of the body to another.  

Production of Blood

Blood cells are produced in the bone marrow. The bone marrow produces up to 95% of the body’s blood cells. Haemopoiesis or hematopoiesis refers to the continuous production of cellular constituents of blood in the bone marrow. It ensures replenishment as needed.

Composition of Blood

Blood contains several blood cells and proteins suspended in a liquid called plasma. The presence of cells and other structures makes the blood thicker than water.

The main components of blood are as follows:

• Red blood cells or erythrocytes
• White blood cells or leukocytes
• Blood platelets or thrombocytes
• Plasma

Some other components of blood are

• Glucose  
• Hormones
• Proteins
• Mineral salts
• Fats
• Vitamins

Pathway of Blood In the Human Heart

It is essential to study the blood flow pathway to understand its functions. Blood flows in the following order through our hearts.

Body → inferior/superior vena cava → right atrium → via tricuspid valve → right ventricle → pulmonary arteries → lungs → pulmonary veins → left atrium → via mitral or bicuspid valve → left ventricle → via aortic valve → aorta → body → inferior/ superior vena cava.

Functions of Blood

In addition to its primary function of transportation of substances, blood has several other important roles to play. The main functions of blood are 

• It regulates body temperature.
• It checks the water content of the cells.
• The blood maintains the pH by interacting with acids and bases.
• It prevents its loss from the body via a mechanism of clotting/ coagulation. 
• It carries hormones, enzymes, nutrition, respiratory gases, proteins, and other substances to the respective parts of the body.

What is Lymph?

Definition: A colourless and clear fluid containing lymphocytes, the white blood cells, flowing in the lymphatic vessels is called lymph.

Lymph is a slightly alkaline coagulable fluid forming a major part of the lymphatic system. It is found in the lymphatic vessels and reaches out to various body cavities.

Production of Lymph

Lymph formation occurs when the interstitial fluid gets collected through tiny lymph capillaries located throughout the body. Thus, lymph is produced as the affluent of interstitial fluid. The colourless fluid is then transported via lymphatic vessels to lymph nodes. The lymph nodes are associated with cleaning and filtering lymph. It then flows into the lymphatic ducts. Finally, lymph empties into the left or the right subclavian vein and mixes back with blood.

Composition of Lymph

The components of lymph are as follows:

• The lymph plasma contains calcium, blood proteins, phosphorus in smaller amounts, and glucose in higher concentrations. 
• Lymphoma plasma has globin proteins that serve as natural antibodies. 
• Corpuscles of lymph are lymphocytes, which are typically leukocytes and amoeboid cells. 
• It also has carbohydrates, creatinine, urea, chlorides, proteins, and nitrogenous substances.
• Water – 94%

Pathway of Lymph 

The flow of lymph in the human body can be represented as follows:

Intercellular spaces containing interstitial fluids → Lymph capillaries → larger lymph vessels → afferent lymph vessels → lymph nodes → efferent lymphatic vessels → lymph ducts or trunks → two large ducts: right lymphatic duct and left thoracic duct → the right lymphatic duct drains into the junction of the right internal jugular and right subclavian veins. In contrast, the left thoracic duct drains into the junction of the right internal jugular and right subclavian veins.

Functions of Lymph

The main functions of lymph are as follows:

• It transports the white blood cells within the lymph nodes and bones.
• It assists in removing interstitial fluid from tissues.
• It fights against infectious bacteria.
• Maintains supply of nutrients to the body
• Gets rid of metabolic wastes from the tissue cells
• Regulates the composition of tissue fluid
• Absorbs digested fats and fat-soluble vitamins from the small intestine via lymphatic vessels

Difference Between Blood and Lymph

The differences and similarities between blood and lymph are amongst the most important biology concepts. It is important not just for CBSE class 10th exams but also for NEET. Students can check out the NEET Biology Syllabus to understand the value of the topic.

The following table enumerates the points of difference between blood and lymph based on various characteristics of the two.

Similarities between Blood and Lymph

Despite several points of difference between blood and lymph, there are a few similarities between them.  

• Both blood and lymph are types of circulatory fluids.
• They circulate in the body within vessels.
• The two fluids also have an immune function in the body.
• A system of capillaries joins together both the fluids. 

Bottomline 

Although there are a few similarities between blood and lymph, such as assisting in the transportation of various body nutrients, oxygen, minerals, and other important substances, there are several differences between the two. While blood is red, lymph is colourless. From a difference in their colours to functions, the two fluids significantly differ from one another. Although the composition of the two fluids is somewhat similar, it is not identical. The varying composition leads to major points of difference between blood and lymph in terms of their function. Students can check out NCERT Solutions for Class 10 Science to get the best understanding of answers related to blood and lymph.

FAQs 

1. What is the composition of lymph?

Lymph is quite similar to plasma in terms of composition. However, it contains lesser amounts of calcium, blood proteins, and phosphorus. Lymph has a high glucose concentration. Furthermore, there are globulin proteins present in lymph plasma. The lymph plasma has lymphocytes that serve immunity defence purposes. There are two types of lymphocytes, namely B lymphocytes and T lymphocytes. Some other components of lymph are carbohydrates, creatinine, urea, chlorides, fibrinogen, albumin, non-protein nitrogenous substances, and a meagre amount of fats. Lymph has 94% water content.

2. Why is blood red but lymph colourless?

Haemoglobin, the red coloured pigment present in the blood, imparts a bright red colour to the body fluid. Haemoglobin is present in the red blood cells. Haemoglobin is an iron-containing protein that efficiently transfers oxygen from respiratory organs to other parts of the body. However, lymph lacks red blood cells, and thus haemoglobin is absent in lymph. The absence of the colour-imparting pigment- haemoglobin, makes lymph colourless.

3. Why is blood a connective tissue?

Blood is a fluid connective tissue. It contains cells and cell fragments suspended in plasma, just like other connective tissues. The following reasons help understand why blood is referred to as connective tissue:

• It is similar to other connective tissues in its embryological constituency. It comprises three main structures of the connective tissue – cell, matrix, and fibres. 
• It networks throughout the body and brings along required nutrients, oxygen, hormones, and other molecules. 

4. What is a blood group?

We can classify blood into various blood groups based on the presence or absence of antibodies and inherited differences in antigenic substances on the surface of red blood cells. Karl Landsteiner’s ABO system of blood groups is the most popular grouping system. It contains four main blood groups: type A, type B, type O, and type AB blood. It is crucial to determine the blood group of a patient before blood transfusion because incompatible blood group transfusion leads to agglutination and destruction of red blood cells.

5. How do the four types of blood groups differ from one another?

The four blood groups differ as follows:

• Group A has A antigens on the surfaces of blood cells. It contains anti-B antibodies in the plasma.
• Group B has B antigens on the surfaces of blood cells. It contains anti-A antibodies in the plasma.
• Group AB has both A and B antigens on the surfaces of blood cells. However, it does not contain any antibodies in the plasma.
• Group O has no antigens on the surfaces of blood cells. In contrast to the group AB, it has both anti-B and anti-A antibodies in the plasma.

6. Which substance is involved in the coagulation of blood and lymph?

Fibrinogen, a protein produced in the liver, is responsible for blood clotting or coagulation of lymph. This protein plays a major role in preventing excess loss of blood from the injury site by forming blood clots. When an injury occurs, fibrinogen converts to fibrin in the presence of thrombin. A cross-linked fibrin network forms at the injury site and binds together plasma proteins and platelets in a hemostatic plug. Blood cells, including erythrocytes and leukocytes, get trapped in the mesh, preventing further blood loss. Thus, it is vital to have optimal amounts of fibrinogen in the body.