Difference between Blood and Lymph, Practice Problems and FAQs

Getting injuries while playing outdoor games is a common thing. What will you do if you get an injury? You will clean the wound and apply some ointments or cover it with a band aid. So that the blood flow gets reduced and microorganisms won’t enter through cuts. The flow of blood through the injury depends on the size of the cut. Why is the blood flowing through the cut from the body? It is because the blood is flowing through our whole body by carrying many things like oxygen, proteins, glucose, water, amino acids etc. which are needed for the metabolic processes in the body. So blood is a transporting fluid in our body.

Fig: Injury on hand

Is blood the only fluid inside our body? The answer is no. There is another fluid called lymph. So what is the function of this fluid? It is a parallel transporting body fluid. It helps in immunity and transport in our body. It is actually formed when the blood in the capillaries oozes out into the intercellular spaces. Only the liquid part (plasma and WBCs) enters the intercellular space and it is called ‘tissue fluid or interstitial fluid’. When the tissue fluid enters the lymph vessel it is called lymph. Since RBCs are not entering the interstitial fluid, the lymph will not be carrying haemoglobin which gives the red colour. Hence the lymph will not be in red colour. This is one difference between the blood and lymph. What are the other differences between them? Let’s discuss more about it through this article.

Table of contents

• Blood
• Lymph
• Difference between blood and lymph
• Practice Problems
• FAQs

Blood

The fluid connective tissue which is responsible for the transport of oxygen and nutrients throughout the body is called blood. The removal of carbon dioxide and waste products also takes place through blood. It is a thick and homogeneous liquid where the blood cells are suspended. The colour of human blood is red, because of the presence of an iron containing pigment called haemoglobin.

Fig: Blood

Components of blood

4 - 6 litres of blood is present in an average adult person. It forms about 6 - 10% of the body weight. The major components of blood are as follows:

• Plasma
• Formed elements

Fig: Composition of blood

Plasma

The watery and straw coloured alkaline viscous fluid and the extracellular material of the blood is called plasma. All the formed elements are floating in the plasma. 55% of the total blood volume is composed by the plasma. Plasma is made up of 90 - 92 % of water and 6 - 8% of proteins. The major components of plasma are as follows:

• Proteins
• Inorganic salts
• Dissolved gases
• Waste products
• Clotting factors
• Blood sugar
• Blood cholesterol

Formed elements

The formed elements constitute 45% of the total blood volume. The formed elements are as follows:

• Erythrocytes, red blood cells or RBCs
• Leukocytes, white blood cells or WBCs
• Thrombocytes or platelets

Fig: Formed elements

Lymph

The colourless mobile liquid present in the lymphatic system is called lymph. It contains water, ions, nutrients, hormones, proteins and WBCs.

Fig: Lymph vessel with lymph

Components of lymph

Lymph originates from the interstitial fluid. Since the chemicals are constantly exchanged between the blood and interstitial fluid, the composition of lymph changes accordingly. The lymph from the intestine is milky white and it is called chyle. It has fatty acids and cholesterol. The components of lymph are as follows:

• Lymph plasma
• Corpuscles

Lymph plasma

The straw coloured fluid of the lymph is called lymph plasma. It is also a major factor for exchanging gases and nutrients between the cells and the blood. It has a lesser amount of calcium and higher amount of glucose when compared with blood. Immunoglobulins (natural antibodies) are also present in the lymph plasma.

Fig: Composition of plasma

Corpuscles

Leukocytes or WBCs are the major corpuscles present in the lymph. They are amoeboid cells so that it can easily ooze out through the capillaries into the intercellular space between the cells and then into the lymph vessel. More lymphocytes (a type of WBC) are present in the lymph than any other types of WBCs.

Fig: Lymphocyte

Some specialised lymphocytes like the B and T lymphocytes, which increase the immune responses are also present in the lymph. Red blood cells or RBCs are absent in the lymph.

Fig: Formation of T and B-lymphocytes

Difference between blood and lymph

The major differences between blood and lymph are as follows:

Practice Problems

1. Which of the following are the components of lymph?

1. Lymph plasma, RBCs and WBCs
2. RBCs, WBCs, and Lymphocytes
3. Lymph plasma, B lymphocytes and T lymphocytes
4. RBCs, WBCs and Platelets

Solution: Lymph originates from the interstitial fluid. Since the chemicals are constantly exchanged between the blood and interstitial fluid, the composition of lymph changes accordingly. The components of lymph are Lymph plasma and corpuscles. Leukocytes or WBCs are the major corpuscles present in the lymph. They are amoeboid cells so that it can easily ooze out through the capillaries into the intercellular spaces between the cells and then into the lymph vessels. More lymphocytes (a type of WBCs) are present in the lymph than any other types of WBCs. Some specialised lymphocytes like the B and T lymphocytes, which increase the immune responses are also present in the lymph. Red blood cells or RBCs are absent in the lymph. Hence the correct option is c.

Fig: Lymph vessel with lymph

2. Which are the formed elements of blood?

1. Erythrocytes, leukocytes and platelets
2. Thrombocytes, RBCs, and Plasma
3. RBCs, plasma and clotting factors
4. All the above

Solution: The fluid connective tissue which is responsible for the transport of oxygen and nutrients throughout the body is called blood. The removal of carbon dioxide and waste products also takes place through blood. It is a thick and homogeneous liquid where the blood cells are suspended. 4 - 6 litres of blood is present in an average person. It forms about 6 - 10% of the body weight. The major components of blood are plasma and formed elements. The formed elements constitute 45% of the total blood volume. The formed elements are erythrocytes (red blood cells or RBCs), leukocytes (white blood cells or WBCs) and thrombocytes or platelets. Hence the correct option is a.

Fig: Formed elements

3. Which of the following statements is wrong about blood?

1. The site of formation of blood is bone marrow
2. The path of blood is through arteries, veins, capillaries and heart
3. Concentration of protein is less
4. Blood moves in a circular motion

Solution: Blood is the red colured fluid that passes through the circulatory system. The site of formation of blood is bone marrow. It contains WBCs, RBCs, platelets, plasma proteins, glucose, water, amino acids etc. The path of blood is through arteries, veins, capillaries and heart. It is the major transporting body fluid. Concentration of protein is high in the blood. It regulates the body temperature and maintains the pH of the body. It has more fibrinogen and shows rapid clotting. Blood flows comparatively at a fast rate and it moves from the heart and also into the heart, by keeping a circular motion. Hence the correct option is c.

4. In which component of lymph the immunoglobulins are present?

1. Lymph plasma
2. B lymphocytes
3. T lymphocytes
4. Red blood cells

Solution: The straw coloured fluid of the lymph is called lymph plasma. It is also a major factor for exchanging gases and nutrients between the cells and the blood. It has a lesser amount of calcium and higher amount of glucose when compared with blood. Immunoglobulins (natural antibodies) are also present in the lymph plasma. Hence the correct option is a.

FAQs

1. What is serum?
Answer: The liquid portion of the blood that remains after coagulation of blood is called serum. The components of serum are inorganic salts (electrolytes), antibodies, antigens, and hormones. Clotting factors are absent in serum.

2. Which are the proteins present in blood plasma?
Answer: The major proteins present in the plasma are fibrinogen, globulins and albumins. For coagulation or clotting of blood fibrinogens are required. The defence mechanism or immunity of the body is maintained by the globulins. The osmotic balance of the body is maintained by albumins and it is the most abundant protein of blood plasma.

3. What are the lymphoid organs?
Answer: There are primary and secondary lymphoid organs. The primary lymphoid organs are the thymus and bone marrow. They are the organs that make the lymphocytes which are the immune cells. The secondary lymphoid organs include lymph nodes, the spleen, the tonsils and certain tissue in various mucous membrane layers in the body.

4. What is lymphoedema?
Answer: A chronic condition occurs due to the blockage of the lymphatic system is called lymphoedema. It causes swelling in the body tissues. Swelling can be observed usually in the arms or legs. It can occur as a birth defect or as a symptom of infection.

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