Types of proper connective tissue

I. loose connective tissue

II. Dense connective

I. Loose connective tissue:

• The cells in the matrix are widely distributed and the fibres are loosely woven.
• It generally connects and support various tissues and organs and helps them to resist strain and displacement.
• types-

1. Areolar connective tissue
2. Adipose connective tissue
3. Reticular tissue

1. Areolar connective tissue:

• These are simplest and most widely distributed connective tissues. It has homogenous, transparent, semi-fluid and gelatinous matrix. (glycoprotein, mucin, hyaluronic acid and chondroitin sulphate).
• Matrix contain various types of cells (fibroblast, macrophages, mast cells, lymphocytes, fat cells, plasma cells) and fibres (white collagen fibres, yellow elastic fibres)
• Fibres are loosely arranged and there is space between fibres, areolae, which derives its name.
• Found in continuous layers beneath skin, space between many organs, between muscles, peritoneum and mesentries.

Functions:

• They binds tissues together
• They engulf bacteria and damaged and dead cells
• They secrete heparin and histamine. Heparin is an anticoagulant while histamine causes inflammation reaction
• They produces antibodies

2. Adipose connective tissue:

• It is a modified form of areolar tissue that contain large number of fat cells ( Adipocytes cells).
• Adipocyte is a large, spherical or oval shaped cell, with large fat droplet causing shifting of nucleus to periphery of the cell
• 2 types of adipocytes- white adipocyte- contain a single large fat droplet and Brown adipocyte- contain number of small fat droplets
• Found beneath skin in dermis, mesentries, around kidney, heart and eye balls

• 

Functions:

• As it synthesise, stores and metabolises fat, it is a considerable sourse of energy
• It acts as a shock absorbers around kidney, heart, and eye balls
• It prevent heat loss by forming insulating layer

3. Reticular tissue:

• It is a modified areolar tissue that contains large number of stellate shape reticular cells floating in fluid matrix.
• Reticular cells has number of cytoplasmic processes which are interconnected to form reticular network.
• Reticular cells secretes reticular fibres
• Found-lymph glands, spleen, liver , bone marrow, thymus and tonsils.

Function:

• they are mostly phagocytic cells, helps in defense mechanism of the body

II. Dense (fibrous) connective tissue:

• The fibres dominate over the cells and the matrix in quantity.
• The fibres may be regularly or irregularly arranged
• types:

1. White fibrous tissue ( tendon and sheath)
2. Yellow elastic tissue (Ligament

1. White fibrous tissue:

• It contains fibroblast cells and collagen fibres and very few amount of matrix.
• The dense network of collagen fibres gives great strength.
• it occur in two form- i) tendon and Sheath
• Tendon is the thick bundle of collagen fibres running parallel to each other, giving strong, flexible but inextensible strength. It joins skeletal muscles to bones.
• Sheath is the bundles of collagen fibres lies in a criss-cross manner. It is present in pericardium of heart, dura matter, cornea, capsule of kidney, spinal cord. It also forms covering of cartilage and bones.

2. Yellow elastic tissue:

• These tissues contains numerous and closely packed yellow elastic fibres.
• Elastic fibre are long, straight and branched, they are elastic and flexible.
• They are present in Ligament, also present in wall of blood vessel, vocal cords, respiratory passage and lungs.
• Ligament– It is composed of yellow elastic fibres and some collagen fibres. It join two bone together.

 Proper connective tissue: Areolar, Adipose, Reticular, white fibrous and yellow elastic tissue

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