Tissue

Tissue

Made By : Munaf Ahmad

Ansari

What is a tissue? A tissue is a cluster of cells which perform a

specific function in a body.

Tissues are of two types: 1)Plant Tissue 2)Animal Tissue

Plant TissuePlant Tissues Are Of Two

Types Based On Their Dividing Capacity.

1)Meristematic Tissues2)Permanent Tissues

Plant Cells

Meristematic Tissue: It consists of actively

dividing cells.It is of three types:

1) Apical Meristem2) Intercalary Meristem

3) Lateral Meristem

Apical Meristem: Present at the growing tips of stem and roots.

Important Functions: To increase the length of stem and root.

Intercalary Meristem: Present at the base of leaves or introdes.

Important Functions: For the longitudinal growth of stem and root

Lateral Meristem: Present on the lateral sides of the stem and root.

Important Functions: To increase the thickness of the stem and root.

Permanent Tissue: The tissues which take up a specific

role and loose the ability to divide are called permanent tissue.

It is of two types:1) Simple Permanent Tissue

2) Complex Permanent Tissue

Simple Permanent Tissue: It consist of only one type of cell.

It is divided into four types:1) Parenchyma2) Collenchyma3) Sclerenchyma4) Protective Tissue

Parenchyma: It is composed of unspecialized living cells with relatively thin cell walls, intercellular spaces.

It is present in soft parts of the plant.

Collenchyma: Composed of living and elongated cells with less cell walls irregular thickened at the corners. No intercellular spaces. It provides mechanical support to plants. It helps in bending of leaves and stems.

Sclerenchyma: It is composed of long, narrow and thick walled cells. This tissue is made up of dead cells and there are no intercellular spaces. Sclerenchyma cells are dead, present in seeds, nuts, husk of coconut, fibers of jute etc.

Complex Permanent Tissue (Conducting tissue): It is made up of more than one type of cells.

It is of two types:1) Xylem2) Phloem

Xylem: Conducts water and minerals from roots to different parts of the plant.

It is composed of four types of cells:1) Trachieds2) Vessels3) Xylem4) Parenchyma5) Fibers

Phloem: Conducts food materials from leaves to the different parts of the plant.

It is composed of four types of cells1) Sieve Tubes2) Companion Cells3) Phloem Parenchyma4) Phloem Fibers

Animal Tissue : It is classified into four major categories based on

their functions.1)Epithelial

2)Connective3)Muscular4)Nervous

Epithelial: It forms the covering of the external surfaces, internal cavities and organs of the animal body.

It is of three types:1) Simple Squamous Epithelium2) Coboidal Epithelium3) Columnar Epithelium

Simple Squamous Epithelium: Single layer of flat cells.

Location in the human body: Lining of the mouth, oesophagous, lung alveoli etc.

Coboidal Epithelium: Consists of cube like cells.

Location in the human body: Lining of the kidney tubules and ducts of the salivary gland.

It’s function is secretion and absorption.

Columnar Epithelium: Consists of elongated or column like cells.

Location in the human body: Inner lining of the intestine and gut.

It’s function is of secretion and absorption.

Connective Tissue: Specialized to connect various body organs.

It is of five types:1) Areoler Tissue 2) Adipose Tissue3) Dense Regular Connective Tissue4) Skeletal Tissue5) Fluid Tissue

Areoler Tissue: Found in the skin and muscles to bones, around the blood vessels, nerves etc.

Adipose Tissue: Acts as the storage site of fats; found between the internal organs and below the skin; acts as the insulator for the body.

Dense Regular Connective Tissue: Main components are tendons and ligaments; tendons connect muscle to bones, while ligaments connects two bones togather.

Skeletal Tissue: Main components of skeletal tissues are cartilage and bone.

Fluid Tissue: Blood is the vascular tissue present in animals.

Muscular Tissue: Main function of this tissue is to provide movement to the body.

It is of three types:1) Striated Muscles or Skeletal Muscles or

Voluntary Muscles2) Smooth Muscles or Involuntary Muscles3) Cardiac Muscles or Involuntary Muscles

Striated Muscles or Skeletal Muscles or Voluntary Muscles: Cells are cylindrical, un-branched and multinucleate.

Smooth Muscles or Involuntary Muscles: Cells are long, spindle-shaped and posses a single nucleus.

Cardiac Muscles or Involuntary Muscles: Cells are cylindrical, branched, and uninucleate.

Nervous Tissue: Present in brain, spinal cord, nerves.

Neurons are the cells of nervous tissue.A neuron consists of a cell body, an axon and a

dendrite.It is present in heart.

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