Chapter 6

"Tissues"

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Facts that matter

Tissues - Group of cells have a common origin and similar function are termed as tissues.

(A) Plant tissues : On the basic of the dividing capacity, plant tissues are of two types.

1. Meristematic tissues

2. Permanent tissues

1. Meristematic tissues : Consists of actively dividing cells . Meristematic tissues are of three types.

• Apical meristem : present at the growing tips of stems and roots. Important function: to increase the length of stems and roots.

• Intercalary meristem - present at the base of leaves and internodes. Important function: for the longitudinal growth of plants.

• Lateral meristem - present on the lateral sides of the stems and roots.important function: to increase the thickness of stems and roots.

2. Permanent tissues - Formed from meristematic tissues,the cells in the tissue loose the ability to the divider permanent tissues are divided into two categories.

• Simple permanent tissues: consists of only one type of cells.

Types of simple permanent tissues:

  • Parenchyma : composed of unspecialised Living cells with relatively thin cell walls, intercellular space, present in the soft parts of the plant. Their main function is storage.

  • Collenchyma - composed of living and elongated cells with cell walls irregularly thickened at the comers. No intercellular space. It provides mechanical support and elasticity to plant.it helps in bending of leaves and stems.

  • Sclerenchyma - Composed of long narrow, and thick walled cells. The tissue is made up of dead cells and there are no intercellular spaces. Sclerenchyma cells are dead, present in seeds,nuts, the husk of a coconut, fibers of jute, etc.

• Complex permanent tissues- made up of more than one type of cells (conducting tissues)

Types of complex permanent tissues:

  • Xylem - Conducts water and minerals from the roots to the different parts of the plant. Composed of four different types of cells- tracheids, vessels, xylem parenchyma and xylem fibres.

  • Phloem - conducts food material from the leaves to the different parts of the plant.

Composed of four different types of cells- sieve tubes, companion cells, phloem parenchyma and phloem fibers.

  • Protective tissues - it is made of a single layer of cells. E.g., epidermis. The epidermis of the leaf bear stomata.

(B) Animal tissue : Animal tissues are classified into four types based

On the functions they perform:

1 Epithelial

2 Connective

3 Muscular

4 Nervous

1. Epithelial Tissues - Form the covering of the external surface,internal cavities and organs of the animal body. Various types of epithelial Tissues are:

  • simple squamous epithelium- single layer of flat cells. Location in the human body: lining of the mouth, oesophagus, lung, alveoli,etc.

  • Cuboidal epithelium - consists of cube like cells. Location in the human body lining of the kidney tubules and ducts of the salvary glands.it's function is secretion and absorption.

  • Columnar epithelium - consists of elengated or column -like cells. Location in the human body: inner lining of the intestine and gut.its function is secretion and absorption.

2 . Connective tissues : specialised to connect various body organs. Various types of connective tissues; are:

  • Areolar tissue - Found in the skin and muscles, around the blood vessels, nervous,etc.

  • Adipose tissues - acts as the storage site of fats; found between the internal organs and below the skin; acts as an insulator for the body.

  • Dense regular collective tissues - mains components are tendons and ligaments, tendons connect muscles to bones, while ligaments connect two bones together.

  • Skeletal tissue - main component of skeletal tissues are caritage and bone.

  • Fluid tissue - Blood is the vascular tissue present in animals.

3. Muscular tissues - Main function of muscular tissues is a provide movement to the body.muscular tissues are of three types:

  • straited muscles or Skeletal muscles or voluntary muscles : cells are cylindrical, unbranched and multinucleate.

  • smooth muscles are involuntary muscles : cells are long, spindle shaped and possess a single nucleus.

  • Cardiac muscles or involuntary muscles: Cells are cylindrical branched and uninucleate.

4 . Nervous tissues - Present in the brain,spinal cord and nerves.

• Neuron - Cells of the nervous tissue.


• A neuron - Consists of a cell body,an axon and dendrite.


We Hope CBSE/MP Board Class 9th Science Chapter 6 "Tissues" will Help You.

Written By - Divya Bhadouriya