Tissue /Anatomy & physiology

Defination of tissue:-

The tissue is defined as a collection or group of the cells.

• They are related to their intercellular substance.
• The study of the tissue is called histology.

 Classification of tissue:-

👉The tissues are mainly classified in 4 major groups :-

1. Epithelial tissue 
2. Connective tissue 
3. Muscle tissue 
4. Nervous tissue .

1.Epithelial Tissue:-

•Epithelial tissue is define as a layer or the layer of the cells that covering body surfaces and all body cavities,hollow organs,glands and ducts .

Development of the epithelial tissues :-

*The development of the epithelial tissues is done by three germ layer.

•These layers are………….

A. Endoderm

B. Mesoderm

C. Ectoderm

Classification of the epithelium tissue:-

1.Simple epithelium tissue :-

A. Simple Squamous epithelium tissue

B. Cuboidal epithelium tissue 

C. Columnar epithelium tissue.

 2.stratified epithelium tissue:-

A. Stratified squamous epithelium tissue

B. Stratified cuboidal epithelium tissue 

C. Stratified columnar epithelium tissue

D.Transitionalepithelium tissue.

3.Multicellular glands :-

  A. Endocrine glands

  B. Exocrine glands

(1.unicellular,2.multicellular)

  C. Mixed glands.

1.Simple epithelium tissue:-

The simple tissue is divided into three types:-

A. Simple squamous epithelium tissue

B.Cuboidal epithelium tissue

C. Columnar epithelium tissue.

A.Simple squamous epithelium tissue:-

       •It is also known as pavement epithelium tissue

       •It is made up of a single layer of flattened and polygonal cells 

       •The nucleus is prominent into over lying space.

site of occurance:-

•Simple squamous epithelium tissue occurs on alveoli

•Bowman’s capsule of kidney.

Functions of the simple squamous epithelium tissue:-

It is thin, so it allows fast diffusion.

Active transport of of molecules.

B . Cuboidal epithelium tissue:-

Cuboidal epithelium tissue is found at site where there is a high metabolic activity occurs.

• The tissues are present on free surfaces
• They provide a large absorptive area.

Site of occurance:-

1. Nephrons
2. Thyroid glands

C. Columnar epithelium tissue:-

• It is also found at the site where there is a high metabolic activity.
• Cells of this tissues are taller.
• Microvilli are present.

Site of occurrence:-

1. Respiratory tract
2. Digestive system
3. Fallopian tube. 

2.stratified epithelium tissue:-

a . Stratified squamous epithelium tissue:-

• It is multi layer epithelium tissue.

It is also further classified into two types;-

1.Keratinizing epithelium tissue

2.Non keratinizing epithelium tissue.

1. Keratinizing epithelium tissue:-

• In this tissue keratin protein is present, so they are called keratinizing Tissue.
• The keratinizing tissues are found on lips, nostrils,gums,outermembrane of the tympanic membrane. 

2.Non keratinizing epithelium tissue:-

• These tissue the keratin protein absent so they are called non keratinizing epithelium tissue.
• They are found at oropharynx, buccal cavity, oesophagus, inner lid of eye lids.
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B. Stratified cuboidal epithelium tissue:-

• It is made up of multiple layer of cells.
• These cells are cube shaped.
• It is seen in the ducts of sweat gland

C. Stratified columnar epithelium tissue:-

• It is rare.
• It is made up of multiple layer of cells
• These cells are columnar shaped.
• It may be seen and some part of male urethra.

D. Transitional epithelium tissue:-

• It is also known as urothelium.
• It is made up of several layers of pear shaped Cells.
• It is found on urinary bladder, ureter.

*Some cells are present singly or in groups are called glands.

Classification of glands:-

a.Endocrine glands

b.Exocrine glands

c.Mixed glands.

a.Endocrine glands:-

• These glands secrete their secretions directly into the blood.
• They are ductless glands
• Ex-thyroid gland 

b. Exocrine glands:-

• These glands secrete their secretions into to blood through the duct.
• Ex-sweat glands 

c.Mixed glands :-

• There are some glands which having both exocrine and endocrine functions.
• Ex-pancreas gland.

2.Connective tissue:-

• The connective tissue connect various structure of our body with each other.
• It is also known as supporting tissue or communicative tissue.
• It is developed from mesoderm layer of embryo.

Components of connective tissue :-

There are are three basic components of connective tissue:-

1. Intercellularsubstance

2. Fibres of connective tissue

3. Cells of connective tissue.

1.Intercellular substances:-

• It is also known as in the matrix.
• The cells are live in intercellular substances
• The provides support to tissue.
• The help in diffusion between blood capillaries and cells

properties of intercellular substances:-

• It is a transparent.
• It is colourless and homogenous.

composition of intercellular substances:-

• the intercellular substances are composed of glycoprotein,glycosaminoglycans.

2.Fibres of the connective tissue:-

There are three main types of fibres:

A. Collagen fibers

B. Reticular fibers

C.  Elastic fibers.

A. Collagen fibers:-

• Collagen fibers are found in all connective tissue.
• They are made up of polypeptides.
• They are more tough.
• They are also known as white fibers.
• These fibers are soft and flexible.

 Types of collagen fibers:-

There are many five types of collagen fibers.

Type 1st:- site of occurrence is:- tendons, bones, dermis of skin.

Type 2nd:- site of occurrence is cartilage.

Type3:- site of occurrence is blood vessels, uterus, skin.

Type 4:-site of occurrence is Basal laminas

Type 5:- site of occurrence are blood vessels, fetal membrane.

B.Reticular fibers:-

• Reticular fibers are very fine fibers.
• They are arranged as net like structure.

These fibres are found in:-

1. Lungs
2. Lymphoid tissues.

C.Elastic fibers:-

• The elastic fibers are long, thin and highly cylindrical structure.
• These fibers are yellow in colour.
•  They are also known as yellow elastic fibers.

The elastic fibres are found in:-

1. Walls of major blood vessel
2. Auricle(pinna)
3. Epiglottis

3.Cells of the connective tissue:-

The cells of connective tissue are:-

1. Mast cells
2. Macrophages
3. Fibroblast
4. Pigment cells.
5. Fat cells
6. Undifferentiated mesenchymal cells
7. Blood leukocytes.

1. Mast cells:-

• It is also known as ‘mastocytes’
• Mast cells are present in groups.
• These cells secrete heparin, histamine, and serotonin in allergic reactions.

Functions of the mast cells:-

• The mast cells help in wound healing.
• Defence against pathogens.

2. fat cells:-

• The fat cells are also known as lipocytes/Adipocytes
• The fat cells are large cells
• The nucleus in fatscells is flattened.

3. Macrophages:-

• The macrophages are found in highly vascular areas.
• These are irregular cells
• These cells help in phagocytosis
• They help in immunological reaction of the body
• They secrete important substances.

Ex-enzymes.

4. Fibroblast cells:-

• Fibroblast cells occur in large numbers.
• They are responsible for the production of the fibers
• Dead cells are large,flat and branching cells.

5. pigment cells:-

• Pigment cells are found in skin, Piamater and choroid part of eye.
• The main pigment of pigment cell is melanin.
• The main function of pigment cell is;-to protect the deeper tissues from ultraviolet rays.

6. Undifferentiated mesenchymal cells:- 

• These cells are developed from mesoderm.
• These cells are found around the blood vessels.
• They are pleuripotant cells .

7. Blood leukocytes:-

The leukocytes are transported by blood 

They are divided into two types:-

A. Lymphocytes

B. Eosinophils.

👉Classification of the connective tissue:-

1.Loose connective tissue:-

A. Adipose tissue

B. Lymphoid tissue

2. Dense connective tissue:-

A. Fibrous tissue

B. Elastic tissue

3. Cartilage tissue:-

A. Hyaline cartilage tissue

B. Fibro cartilage tissue

C. Elastic cartilage tissue

4. Bone tissue

5. Blood tissue.

1. Loose connective tissue:-

• It is found in almost every part of body.
• It contains less fibres more cells
• It contain fat cells, macrophages, and mast cell.
• These cells and fibers are loosely arranged.

Function of loose connective tissue:-

• It provides elasticity and strength.
• It connects and support the other tissue.

Types of loose connective tissue:-

1. Adipose tissue

2. Lymphoid tissue.

 1. Adipose tissue:-

• It is made up of fat cells.
• It contains large fat globules.

functions of adipose tissue:-

• it occurs as a store of energy.
• It support and protect the organ.
• It help in temperature maintenance.

2.Lymphoid tissue:-

• it is also known as reticu lar tissue.
• It contain mostly reticular fibers.
• It is found in lymph nodes and all organ of lymphatic system.

2. Dense connective tissue:-

• It contains more fibers and less cells.

Types of dense connective tissue:-

There are two types of dense connective tissue……

A. Fibrous tissue 

B. Elastic tissue 

A.Fibrous tissue:-

• fibrous tissue contains collagen fibres with little matrix.
• It forms outer covering of bone, kidney and brain.

B. Elastic tissue:-

• Elastic tissue is made up of elastic fibres.
• They have capacity of extension and recoil.

It occurs in………

1. Walls of large blood vessels.
2. Trachea
3. Bronchi and lungs.

3. Cartilage tissue:-

• Cartilage tissue is firmer than other connective tissue except bone.
• It consists of chondrocytes, collagen and elastic fibres.
• The mature cells of cartilage is called 'chondrocytes’

Types of cartilage tissue:-

1. Hyaline cartilage
2. Fibro cartilage.
3. Elastic cartilage.

A. Hyaline cartilage:-

• Hyaline cartilage is smooth bluis-white issue.
•  The chondrocytes are present in small groups.
• It provide flexibility and smooth surface for the movement of joints.

It founds:-

1. Trachea
2. Part of larynx
3. Anterior and of ribs

B. Fibrocartilage:-

• Fibrocartilage is made up of collagen fibres.
• It is strongest cartilage tissue.

It is found:-……

1. Intervertebral disc.
2. Between articular surface of bones.

C. Elastic cartilage:-

• It is made up of elastic fibres.
• The chondrocytes lies between the fibres. 
• It provides support and maintenance shape.

It is found:-

1. At Wall of large blood vessels
2. Epiglottis 
3. Panna.

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