Connective Tissue: Its Components, Loose Connective Tissue, Practice Problems and FAQs

We all look at high rising buildings and wonder about the construction. You all know that cement helps to connect the bricks of these buildings. Can you make a tall building without cement? Not possible.

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Fig: Cement

Similarly, in our body many types of tissues are present and they are working in a coordinated manner like bricks in the building. So there must be a special tissue that helps in connecting other tissues in our body. It is called connective tissue which connects different parts of the body. A complex body is composed of various structures that are connected to one another too.

The most common example of connective tissue is the blood. It is the fluid connective tissue which transports various substances, such as nutrients, hormones, and oxygen from one part of the body to another. Our body has many other types of connective tissues like bone, cartilage etc. Bone provides the structural framework to the human body. Let’s understand more about connective tissues in this article.

Table of contents:

Connective tissue
Components of connective tissue
Types of connective tissues
Loose connective tissue
Practice Problems
FAQs

Connective tissue

It is the most abundant tissue which is distributed widely in the complex animal. The primary function of connective tissue is to link and support other tissues and organs of the body. They are of different types from soft tissues to specialised tissues.

GIF: Connective tissue

Components of connective tissue

It possesses three components as follows:

Ground substance
Connective tissue cells
Fibres

Ground substance

It is a non-living, amorphous and transparent semi-fluid. It possesses mainly carbohydrates and proteins. The most common mucopolysaccharide present is hyaluronic acid.

Connective tissue cells

They are the living component. They are of various types depending on the type of connective tissue. Examples include fibroblasts, adipose cells, plasma cells, mast cells, macrophages, reticular cells, lymphocytes etc.

Fibroblasts

They are spindle-shaped cells and produce fibres and matrices.

Adipose cells

They are spherical cells which store fats.

Plasma cells

They help in the production of antibodies and assist in immune response.

Mast cells

They produce histamine, heparin and serotonin. They are involved in inflammatory responses.

Macrophages

They help in ingesting bacteria, foreign substances and cell debris.

Reticular cells

They help in the formation of reticular fibres and are phagocytic in nature.

Lymphocytes

They are small and spherical cells. They are involved in immune response.

Fibres

They are of three types as follows:

Collagen fibres

They are the white fibres. They are made up of collagen proteins. They are unbranched and inelastic. They occur in bundles. On boiling in water they change to elastin protein.

Elastic fibres

They are the yellow fibres. They are formed of elastin protein. They are elastic and branched. They show resistance to boiling.

Reticular fibres

They are made up of reticulin proteins. They are branched and inelastic. They are delicate and form a reticulum or network.

Types of connective tissue

The three types of connective tissues are as follows:

Loose connective tissue
Dense connective tissue
Specialised connective tissue

Loose connective tissue

In a semi-fluid ground substance, the cells and fibres are loosely arranged. It acts as a binding tissue. There are two types of loose connective tissue as follows:

Areolar tissue
Adipose tissue

Areolar tissue

It is primarily found under the skin. It acts as a supporting agent of the epithelium. It occurs beneath the epithelia of many visceral organs, walls of veins and arteries. It fixes the skin with the muscles. It possesses three types of cells as follows:

Macrophages

They are large amoeboid cells which are phagocytic in nature. They phagocytose and destroy microbes, foreign particles and cell debris.

Fibroblasts

They are irregularly shaped cells which secrete collagen and elastin proteins. Collagen fibres help in tissue repair. The fibres of the tissue leave spaces called areolae between them, hence the name areolar tissue.

Mast cells

These cells secrete histamine, serotonin, heparin and matrix. Heparin prevents blood clotting. Histamine is involved in allergic and inflammatory responses. It attracts the phagocytes to the tissue injury sites.

Fig: Areolar tissue

Functions of areolar tissue

It allows the migration of wandering cells towards the areas of infections and repair.
It binds parts together.
It provides strength, elasticity and support to the body parts.
It allows the diffusion of materials

Adipose tissue

It is subcutaneous tissue made up of adipocytes. These cells store fats. The excess nutrients are converted to fats and stored in adipose tissues. Adipocytes possess fat globules which displace the nucleus and cytoplasm to the periphery. The blubber of whales, hump of camels and yellow bone marrow contains adipose tissue. It forms a shock absorbing cushion around the heart, kidneys, etc. It prevents heat loss from the body.

Fig: Adipose tissue

Functions of adipose tissue

It stores fats.
It acts as a shock absorbing cushion normally around the heart, kidneys, eye balls etc.
It prevents heat loss from the body.
It gives features to the body.

Practice Problems

Q1. From the given options, which type of connective tissue provides a framework to support epithelium?

A. Areolar tissue
B. Adipose tissue
C. Dense regular connective tissue
D. Dense irregular connective tissue

Solution: Areolar tissue is mostly located beneath the skin. It functions as an epithelial supporter. It consists of macrophages, mast cells and fibroblasts. It occurs beneath the epithelia of many visceral organs, walls of veins and arteries. It fixes the skin with the muscles. Hence, the correct option is a.

Q2. Excess nutrients that are not required by the body cells immediately are converted into ____________.

A. Areolar tissue
B. Adipose tissue
C. Dense regular connective tissue
D. Dense irregular connective tissue

Solution: Adipocytes make up the subcutaneous tissue. Fats are stored in these cells. Excess nutrients are converted to fats, which are then deposited in adipose tissues. Hence, the correct option is b.

Q3. Identify the figure and recognise the correct labelling of the given figure.

Answer: In the given image, ‘a’ represents macrophages, ‘b’ represents fibroblasts and ‘c’ represents mast cells.

Macrophages are large amoeboid cells which are phagocytic in nature.
Fibroblasts are irregularly shaped cells which secrete collagen and elastin fibres.
Mast cells secrete histamine, serotonin, heparin and matrix.

Q4. Areolar connective tissue joins ______________.

A. fat body with muscles
B. integument with muscles
C. bones with muscles
D. bones with bones

Solution: Areolar tissue connects the integument to the muscles and is a form of connective tissue. An integument is nothing more than a layer of skin. It acts as a support structure for the epithelium. Hence, the correct option is b.

Q5. What role does ground substances play in connective tissue?
Answer: Ground substance is a gel-like matrix in which all other connective tissue elements are embedded. Ground substance connects all the elements of connective tissue.

Q6. Differentiate between collagen fibres and elastic fibres.
Answer: The difference between collagen fibres and elastic fibres are enlisted below:

Collagen fibres	Elastic fibres
They are the white fibres.	They are the yellow fibres.
They are made up of collagen proteins.	They are formed of elastin protein.
They are unbranched and inelastic.	They are elastic and branched.

Q7. Where is the loose connective tissue located?
Answer: The loose connective tissue is commonly found under the skin. It is also present in the bone marrow, lymph nodes and spleen.

FAQs

Q1. How does connective tissue insulate?
Answer: Adipose tissue is a loose connective tissue which cushions the body organs and insulates them. They also provide reserve energy fuel in the form of fat. It prevents loss of heat from the body.

Q2. How do humans use blubber?
Answer: Blubber is used extensively by people for fuel and food. It provides energy rich food. It forms a part of the traditional diets of the Eskimos.

Q3. What is the common use of heparin?
Answer: Heparin injection is used as an anticoagulant. It will be able to decrease the clotting ability of the blood. This helps prevent the formation of harmful clots in blood vessels. This medicine is also called a blood thinner.

Q4. Why is elastin considered as good for skin?
Answer: Elastin allows the skin to stretch and then regain its normal shape. It functions in coordination with collagen. They are found in the connective tissue.