THE TISSUE AND ITS TYPES IN ANIMAL

 

TISSUE IN ANIMAL:-

·         It is the organisation of similar cells which along with intracellular substances perform specific functions, called tissue.

·         There are specialized type of junctions are present between the cells in all type of tissues, which provide structural and functional link between cells in the tissues.

·         Junctions are of three types-

1)     Tight Junctions- To stop leaking of substances across the tissues.

2)     Adhering Junctions- To keep the neighboring cells together via cementing.

3)     Gap junction- To communicating each other through cytoplasm and also help in rapid transfer of ions, small molecules and big molecules.

·         In multicellular animals, four type of tissues are present.

1.       Epithelial tissue

2.       Connective tissue

3.       Macular tissue

4.       Nervous tissue

The Epithelial tissue:-

• The tissue having free surface which present between body fluid and outer environment. The cells of this tissue are completely packed together with lattice intracellular spaces.
• It is also of two types.

1.       Simple epithelium tissues

2.       Compound epithelium tissue

1)   Simple epithelium tissue:-

• It consists of single later of cells and present in the body cavities, ducts and tubes.
• On the basis of structure it also are of three types.

                                             i.            Squamous

                                           ii.            Cuboidal

                                         iii.            Columnar

        I.            Squamous:-

•                    It consist of single thin layer flattened cells with irregular boundary.
•                   They are mostly found in wall of blood vessels, air sac of lungs.
•      It acts like s diffusion boundary.

     II.            Cuboidal:-

•            It consists of single layer of cube cell.
•                    It is found in ducts of glands and tubular part of nephron in kidney.
•      It functions as absorption and secretion.

   III.            Columnar:-

•                  It is a single layer of tall and cylindrical cells having nuclei at the base of cell.
•                  It is lining the stomach and intestine.
•                  It also helps in secretion and absorption.

       

Fig- Simple Epithelium (a) Squamous, (b) Cuboidal, (c) Columnar, (d) Columnar cells bearing cilia.

Ø  Ciliated epithelial-

·         It consist the ciliated columnar and Cuboidal cells.

·         It mainly present in inner surface of hollow organs such as bronchioles and fallopian tubes.

·         It functions to move particles or mucus in specific direction.

Ø  Glandular epithelium-

·         Some cuboidal or columnar cells get specialised for secretion called glandular epithelium.

·         It may be unicellular globular cells (Goblet cells of alimentary canal) or multicellular glandular epithelial cells

·         On the basis of pouring it may be-         

·         Endocrine- It is open through ducts and secretes mucus, saliva, earwax oils, milks, digestive enzymes and other cell products

·         Exocrine- It doesn’t have ducts i.e. it secrete the hormones directly into fluids. 

Fig- Glandular Epithelium (a) Unicellular, (b) Multicellular. 

2)   Compound Epithelum tissue:-

·         It consists of more than one layer of cells.

·         It covers the dry surface of skin, moist surface of buccal cavity, pharynx, inner surface of ducts of salivary gland and pancreatic ducts.

·         Its main function to provide protection against chemical and mechanical strength, only limited role in absorption and secretion.

Fig- Compound Epithelium

      Connective Tissue:-

·         It consists of cartilage, bone, adipose and plasma. It is widely distributed in the whole body.

·         Due to its functions to form a linkage among each other, called connective tissue.

·         All the cells of connective tissue except blood cell secretes fibres of structural protein called collagen or elastin.

·         The fibres functions to provide strength, elasticity, and flexibility to the tissues.

·         It is of three types-

1.       Loose connective tissue

2.       Dense connective tissue

3.       Specialised tissue

1)   Loose Connective Tissue:-

·         It consists of cells and fibres which are loosely arranged in a semi-fluid ground substance. It also contains fibroblast, macrophage and mast cells.

·         It serves to give support for the epithelium.

Examples:-

 Areolar tissue (present beneath the skin) &

 Adipose Tissue- It also another type of loose connective tissue which located just beneath the skin. Its cells contain excess of fats (fat is excess of nutrients which not used by body for output work)

Fig Loose Connective Tissue (a) Areolar Tissue, (b) Adipose Tissue

2)   Dense Connective tissues:-

·         It consists of fibres and fibroblast which are compactly packed.

·         On the basis of orientation of fibres, it is of two types-

1)     Dense Regular Connective Tissue: - In which arrangement of fibres show regular pattern i.e. the collagen fibres are present rows between many parallel bundles of fibres. Ex- tendon and ligament.

2)     Dense Irregular Connective Tissue:- In which arrangement of fibres show irregular Pattern i.e. the fibres and fibroblast are arranged in irregular pattern.

Fig- Dense Connective tissue (a) Dense Regular, (b) Dense Irregular

3)   Specialised Connective Tissue:-

·         It is consists of Cartilage, Bones and Blood.

Ø  Cartilage:-

·         It consists of chondrocytes cells having solid and pliable intracellular material.

·         Its cells are enclosed in small cavities within the matrix secreted by them.

Example-

1.      It is present in vertebrate of embryo which replaced into bones into adult.

2.      It is also present in tip of nose, outer ear joints, Between adjacent bones of the vertebral column, limbs and hand in adult.

Ø  Bones:-

·         It is consist of osteocyte cells having hard and non- pliable ground substance.

·         Ground Substances have calcium salts and collagen fibres which is responsible for its strength.

·         Its main function to give support and protection of Tissue and organ and also help in movement at the region where skeleton muscles interact with it.

·         Bone marrow in some bones is responsible for formation of blood cells.

Ø  Blood:-

·         It is the fluid connective tissue containing Red Blood Cells (RBC), White  Blood Cells (WBC), Plasma and Platelets.

·         It is the main circulatory system and responsible for transportation of various substances.

Muscular Tissue:-

·         It is consists of many long, cylindrical fibres which is arranged parallel to each other. Hare fibre made up of many fibrils called myofibrils.

·         Muscle fibres are contracted (Shorten), when any response occurs and then relaxed (lengthen) to their original state.

·         They play an active role in movement of body.

·         Muscles are of three types- Skeletal, Smooth and Cardiac.

1.     Skeletal Muscle:-

·         It consists of skeleton muscle fibres which arranged parallel to each other and they enclose in a sheath connective tissue.

·         It is closely attached to skeleton bones and present into the typical muscles like the biceps.

2.     Smooth Muscle:-

·         It consists of smooth muscle fibres which are fusiform and held together by cell junctions like bundles and enclosed in a sheath of connective tissue.

·         It is present in walls of internal organ such as blood vessels, stomach and intestine.

·         It can’t directly controlled i.e. we can do this with skeleton muscles.\

3.     Cardiac Muscle Fibres:-

·         It consists of cardiac muscle cells and its cell junction fuse the plasma membrane to make them sticky.

·         It is present only in the heart having some junction at some points on the heart; allow the cell to contract along with neighbour cells.]

Fig- Muscular Tissue (a) Skeletal, (b) Smooth, (c) Cardiac

Neural Tissue:-

·         It consists of nerve cells and nuwrogleal cells. The neural tissue controls the responsiveness of whole body. Here the neuron is stimulated, and electric disturbances is generated which travels with their plasma membrane.

·         Neuralgia cells protect and support neurons. It makes more than one-half of the volume of the neural tissue in the body.

             

Fig- Neural Tissue (Neurons with Neuralgia)

Organ and Organ System:-

·         The tissue constitute together to form organ and organ associate to form organ system.

·         Heart is associated with all type of tissues.

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