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Building Blocks of Life: Different Types of Tissues in Plants and Animals

December 18, 2023 635 0

Exploring the Vital Roles of Different Types of Tissue in Living Organisms

Types of Tissue in living organisms represent specialized groups of cells collaborating to perform specific functions essential for the overall well-being of the organism. These types of  tissues work in harmony, contributing to the overall structure and function of organs and organ systems in living organisms.

Definition: 

  • A group of cells that are similar in structure and/or work together to achieve a particular function forms a tissue. 

Types of Tissues: 

  • There are two types of tissues-
    • Plant Tissues.
    • Animal Tissues.

Plant- From one of the major types of Tissue:

  • Cells in Plant Tissue: Plants are stationary or fixed, and their supporting tissue is made up of dead cells.
  • Division: Based on their ability to divide, plant tissues can be divided into two categories.
  • Meristematic types of Tissue: The growth of plants occurs only in certain specific regions. 
    • This is because the dividing tissue, also known as meristematic tissue, is located only at these points. 
    • Meristematic tissues are classified as apical, lateral and intercalary.
  • Cells of meristematic tissue are very active, they have dense cytoplasm, thin cellulose walls and prominent nuclei. 
  • They lack vacuoles.                
  • Differentiation and Permanent from one of the major types of Tissue: Differentiation of meristematic tissue leads to the development of various types of permanent tissues. 
    • This process of taking up a permanent shape, size, and a function is called differentiation.
Simple Permanent Tissue Complex Permanent Tissue
    • A few layers of cells beneath the epidermis are generally simple permanent tissue.
    • All made of one type of cells, which look like each other
      • Such tissues are called simple permanent tissue.
    • Various types of tissues- Simple:
      • Parenchyma 
      • Collenchyma 
      • Sclerenchyma 
    • Parenchyma: It is the most common simple permanent tissue. 
      • It consists of relatively unspecialised cells with thin cell walls. 
      • They are living cells.
    • Collenchyma: The flexibility in plants is due to collenchyma
      • It allows bending of various parts of a plant like tendrils and stems of climbers without breaking. 
      • It also provides mechanical support.
    • Sclerenchyma: It is the tissue which makes the plant hard and stiff. 
    • For example, the husk of a coconut
      • It is made of sclerenchymatous tissue. 
      • The cells of this tissue are dead.
  • Epidermal cells : It is the outermost layer of cells, Epidermal cells on the aerial parts of the plant often secrete a waxy, water resistant layer on their outer surface.
      • It has a protective role to play, cells of epidermal tissue form a continuous layer without intercellular spaces.
  • Epidermal cells of the roots, whose function is water absorption, commonly bear long hairlike

parts that greatly increase the total absorptive surface area.

  • In some plants like desert plants, epidermis has a thick waxy coating of cut in (chemical substance with waterproof quality) on its outer surface.
  • Complex tissues are made of more than one type of cells. 
    • All these cells coordinate to perform a common function. 
  • Xylem and phloem are examples of such complex tissues
    • They are both conducting tissues and constitute a vascular bundle.
  • Xylem consists of tracheids, vessels, xylem parenchyma, Xylem fibers. 
    • Tracheids and vessels are tubular structures. 
    • This allows them to transport water and minerals vertically.  
    • The parenchyma stores food. 
  • Phloem is made up of five types of cells,sieve cells, sieve tubes, companion cells, phloem fibers
  • Phloem transports food from leaves to other parts of the plant.                                                                                                           

 

 

 

 

 

 

 

 

 

Animal- From one of the major types of Tissue:

  • Animal tissue is moving tissue and most cells are living. 
  • On the basis of the functions there are  different types of animal tissues, such as epithelial tissue, connective tissue, muscular tissue and nervous tissue.

 

Epithelial- From one of the major types of Tissue : 

  • The covering or protective tissues in the animal body are epithelial tissues. 
  • Epithelium covers most organs and cavities within the body.
  • The skin, the lining of the mouth, the lining of blood vessels, lung alveoli and kidney tubules are all made of epithelial tissue.
  • Different types of epithelial tissues as listed as under:
    • Squamous: Simple squamous epithelial cells are extremely thin and flat and form a delicate lining. 
      • The esophagus and the lining of the mouth are also covered with squamous epithelium.
    • Stratified Squamous: Stratified squamous epithelium is skin epithelial cells arranged in many layers to prevent wear and tear.
    • Cuboidal: Cuboidal epithelium (with cube-shaped cells) forms the lining of kidney tubules and ducts of salivary glands, where it provides mechanical support.
    • Columnar (Ciliated): Columnar epithelium where absorption and secretion occur, as in the inner lining of the intestine, tall epithelial cells.

 

Connective- From one of the major types of Tissue : 

  • The cells of connective tissue are loosely spaced and embedded in an intercellular matrix. 
    • The matrix may be jelly-like, fluid, dense or rigid.
  • Blood is a type of connective tissue. 
    • Blood has a fluid (liquid) matrix called plasma, in which red blood corpuscles (RBCs), white blood corpuscles (WBCs) and platelets are suspended. 
    • The plasma contains proteins, salts and hormones. 
    • Blood flows and transports gasses, digested food, hormones and waste materials to different parts of the body.
  • Bone is another example of a connective types of tissue. 
    • It forms the framework that supports the body. 
    • It also anchors the muscles and supports the main organs of the body. 
    • It is a strong and nonflexible tissue.  
    • Bone cells  are composed of calcium and phosphorus compounds.
  • Ligaments: Two bones can be connected to each other by another type of connective tissue called the Ligament
    • This tissue is very elastic.
    • It has considerable strength.
  • Tendons connect muscles to bones and are another connective types of tissue.
  • Cartilage is a type of connective tissue, Cartilage smoothens bone surfaces at joints and is also present in the nose, ear, trachea and larynx. 
  • Areolar connective tissue is found between the skin and muscles, around blood vessels and nerves and in the bone marrow. 
    • It fills the space inside the organs, supports internal organs and helps in repairing types of tissues.

Types of Muscles Fibers

  • Striated Muscle: voluntary muscles or skeletal muscles are also called striated muscles.
  • are mostly attached to bones and help in body movement.
  • Smooth Muscles: Also known as  involuntary muscles control The movement of food in the alimentary canal or the contraction and  relaxation of blood .They are also found in the iris of the eye, in ureters and in the bronchi of the lungs.
  • Cardiac Muscles: The muscles of the heart show rhythmic contraction and relaxation throughout life. These are involuntary muscles.

Muscular- From one of the major types of Tissue: 

  • Muscular tissue consists of elongated cells, also called muscle fibers. 
  • These types of tissues are responsible for movement in our body.
  • Muscles contain special proteins called contractile proteins, which contract and relax to cause movement.
nervous tissue
Neuron-unit of nervous tissue

Nervous- From one of the major types of Tissue: 

  • The brain, spinal cord and nerves are all composed of the nervous tissue. 
  • The cells of this type of tissue are called nerve cells or neurons
  • A neuron consists of a cell body with a nucleus and cytoplasm, from which long thin hair-like parts arise . 
    • Each neuron has a single long part (process), called the axon, and many short, branched parts (processes) called dendrites.
  • An individual nerve cell may be up to a meter long.
  • The signal that passes along the nerve fiber is called a nerve impulse.

The functional combination of nerve and muscle tissue is fundamental to most animals. This combination enables animals to move rapidly in response to stimuli.

Conclusion

Understanding cells and types of tissues is pivotal in grasping the foundation of life and disease. It offers insights into our biological essence and holds the key to advancements in healthcare and biotechnology. Comprehensive knowledge of cells and types of tissues is indispensable for unraveling the intricacies of life, health, and disease. It forms the cornerstone of medical research, biotechnology, and regenerative medicine, driving progress in diagnostics and therapeutics, and ultimately, improving the quality of human life.

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UDAAN PRELIMS WALLAH
Comprehensive coverage with a concise format
Integration of PYQ within the booklet
Designed as per recent trends of Prelims questions
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