Specialised Connective Tissue: Blood and Its Components, Reticular, Pigmented and Mucoid Connective Tissue

You all know how we send things from one place to another?

Yes, you are correct.

We are taking either public or personal transport systems to transfer things from one place to another. 

Similarly, in our body there is a mechanism to send things to different parts. We eat food through the mouth which is absorbed in the small intestine. 

How does this absorbed nutrients transported from the small intestine to all the body parts?

Yes, there is a liquid medium in our body that transports all the nutrients, hormones and oxygen. This liquid medium is termed as ‘Blood’. 

Now, you might be thinking how does blood help in transportation? Do you know, bone marrow makes more than 220 billion new blood cells everyday? What is the composition of blood?

Let’s find out the answer to all these questions.

Table of Contents

• Vascular tissue
• Blood
• Reticular connective tissue
• Pigmented connective tissue
• Mucoid tissue
• Summary of types of connective tissues
• Practice Problems
• FAQs

Vascular Tissue

It is a specialised connective tissue in the body. It has a fluid matrix and free cells. Matrix is without fibres. Examples include blood.

Blood

It is a fluid connective tissue which is composed of the matrix called Plasma and formed elements. Formed elements include the blood cells. It is considered as the main fluid that helps in the transportation of various substances across the body. 

Plasma

Plasma is a straw coloured and viscous liquid that constitutes around 55% of the blood. Plasma is composed of 90 - 92% of water and 6 - 8% of proteins. It contains some minerals in small amounts like Na+, Ca++, Cl- etc. Plasma also has some molecules, such as glucose, amino acids, lipids etc. Blood coagulation factors are also present in plasma. The major proteins found in plasma are fibrinogens, globulins and albumins. 

Fibrinogens

They are mainly required for coagulation of blood. 

Globulins 

They are involved mainly in the defence mechanism of the body. 

Albumins

They mainly maintain the osmotic level of the body. 

Serum 

It is the plasma that is devoid of clotting factors.

Erythrocytes or RBCs

They are biconcave disc-like cells that have red colour iron pigment called Haemoglobin. These cells arise from bone marrow and their life span is of 100 - 120 days. In mammals, the RBCs are enucleated i.e. they do not have a well defined nucleus. 

Leucocytes or WBCs

They are white coloured cells and larger than RBCs. Leucocytes are amoeboid in shape and they also arise from bone marrow. They are further divided into two types on the basis of the nature of cytoplasm. These are as follows:

Granulocytes

The cytoplasm of these cells have granules.

Types of granulocytes

Granulocytes are further divided into three types on the basis of staining properties as follows:

• Basophils - They absorb only basic stains like methylene blue. They possess two to three lobed nuclei. They secrete histamine, serotonin and heparin. They form 0.5-1% of the blood cells. 

  

• Eosinophils - They absorb only acidic stains like eosin. They possess a bilobed nucleus. They form around 2-3% of the blood cells. 

  

• Neutrophils - They absorb acidic as well as basic stains. They form 60-65% of the total white blood cells. They possess two - seven lobed nuclei. 

  

Agranulocytes

The cytoplasm of these cells have no granules.

Types of Agranulocytes

They are classified into two categories as follows:

• Monocytes - It has a kidney-shaped nucleus. They are the largest of all white blood cells. They constitute 6-8% of total white blood cells. They are motile and phagocytic in nature. 

  

• Lymphocytes - It has a large and round nucleus and helps in antibody formation. They constitute about 20-25% of the white blood cells. 

  

Platelets or Thrombocytes

They are produced as fragments of large cells. They primarily help in coagulation.

Reticular Connective Tissue

It consists of reticular cells which form a network called the reticulum. The fibres are made up of reticulin. It can be found in the liver, spleen, lymph nodes, and other organs. It helps in bonding the cells of smooth muscles.

Pigmented Connective Tissue

It possesses pigment cells called Chromatophores. Examples include melanocytes. It is present in the iris of the eyes, dermis of the skin etc. 

Mucoid Tissue

It possesses Wharton’s jelly, jelly like substance, collagen fibres and fibroblasts. It is present in the vitreous humour of the eyes. It is the embryonic connective tissue in the foetus.

Summary of Types of Connective Tissues

Practice Problems of Specialised Connective Tissue: Blood

Question 1. When a doctor takes a blood sample, we can see the blood is of red colour. This is due to the presence of _________________.

a. myoglobin
b. haemoglobin
c. fibrinogen
d. albumin

Solution: Haemoglobin is a red colour iron containing compound that gives blood its specific colour. It binds with oxygen and carbon dioxide and transports the gases. Hence, the correct option is b.

Question 2. Identify the components of blood in the given figure?

Solution: In the given figure, ‘a’ represents White blood cells or leucocytes, ‘b’ represents Red blood cells or erythrocytes, ‘c’ represents Plasma and ‘d’ represents Platelets or thrombocytes.

Question 3. When a person gets injured, a mesh-like network is formed after some time to stop bleeding. This is called a blood clot. It is formed due to the presence of ____________.

a. RBCs
b. WBCs
c. plasma
d. platelets

Solution: The presence of platelets causes a blood clot to develop. They become active when bleeding starts and further activates the blood clotting factors. Hence, the correct option is d.

Question 4. The eye colour of a person is blue. Which type of connective tissue is responsible for this?

a. Mucoid connective tissue
b. Pigmented connective tissue
c. Reticular connective tissue
d. Dense connective tissue

Solution: Pigmented connective tissue is responsible for the eye colour. The eye colour varies from person to person. It has chromatophores, which are pigment cells. Hence, the correct option is b.

FAQs of Specialised Connective Tissue: Blood

Question 1. What is the difference between basophils and eosinophils?

Answer: Basophils and eosinophils are the types of granulocytes. Basophils absorb only basic stains like methylene blue whereas eosinophils absorb only acidic stains like eosin.

Question 2. What is plasma without clotting factors called?

Answer: Plasma without clotting factors is known as serum. It is a clear and yellow colour fluid.

Question 3. What is the lifespan of erythrocytes?

Answer: The lifespan of erythrocytes or RBCs is 100 - 120 days.

Question 4. What is the concentration of plasma and formed elements in the blood?

Answer: In a blood, plasma constitutes about 55% of blood and formed elements constitute 45% of the blood.

Related Topics to Connective Tissue Blood in Biology

• Connective Tissues
• Epithelial Tissue
• Connective Tissue Bone
• Connective Tissue Cartilage

NCERT Class 11 Biology Chapters