tissues

• All living organism are made of cells
• Cells specialising in one function are often grouped together in a body.
• A group of cells that are similar in structure and/or work together to achieve a particular function forms a tissue
• Plant

  1. Plants are stationary or fixed— they don't move
  2. They have a large quantity of supportive tissues 
  3. Supportive tissues has dead cells
  4. The growth in plants is limited in certain region
• Animal

  1. Animals move around in search for food and shelter
  2. Consume more energy as compared to plants
  3. Most tissues are living
  4. The growth in animals is not so limited
• The structural organisation of organs and organ systems is far more specialised and localised in complex animals than even in very complex plants 
• Plants are sedentary existence on one hand and active locomotion on the other (animal).
• Plants can be classified as growing or meristematic tissues and permanent tissues.
• Cells growth in animals is more uniform
• Meristematic tissues

  1. The growth of plants occurs only in certain specific regions. This is because dividing tissues, also known as meristematic tissues.
  2. Meristematic tissues are classified as apical lateral and intercalary
  3. Apical meristem is present at the growing tips of stems and roots and increases the length of the stem and the root.
  4. Intercalary meristem seen in siem plants is located near the node.
  5. Cells of meristematic tissues are very active, they have dense cytoplasm, thin cellulose walls are prominent nuclei
  6. They lack vacuoles 
• Permanent tissues

  •  The process of taking up a permanent shape, size and a function is called differentiation.

  Types of permanent tissues.

  1. Simple tissues
  2. Complex tissues
• Simple permanent tissues

  1. Parenchyma
  2. Collenchyma
  3. Sclerenchyma
• Parenchyma is a widely distributed tissue in the plant body, exhibiting characteristics:

  1. Consists specialized cells with thin cell wall.
  2. Living cells
  3. This tissues generally stores food
  4. It contains chlorophyll and performs photosynthesis and it is called chlorenchyma
  5.  Large air cavities are present between the parenchyma cells. Such parenchyma is called aerenchyma.
• Collenchyma is a strong and flexible tissue, is strengthening tissues of growing organs.

  1. It allows bending of various parts of a plant like tendrils and stems of climbers without breaking
  2. It provides mechanical support
  3. This tissues is found in lead stalks below the epidermis
  4. This tissues is living, elongated and irregularly thickened at the corners.
  5. There is a very little intercellular space
• Sclerenchyma is also a strengthening tissues.

  1. It is the tissues which makes the plant hard and stiff
  2. It is made of sclerenchymatous tissue. The cell of this tissues are dead.
  3. They are long and narrow as the walls are thickened due to lignin. These walls are thick that there is no internal space inside the cell.
  4. This tissues is present in stems, around vascular bundles, in the veins of leaves and in the hard covering of seeds and nuts.
  5. It provides strength to the plant parts
• The outermost layer of cells is called epidermis

  1. Usually made of single layer of cells
  2. Epidermal cells on the aerial parts of the plant often secrete a waxy, water-resistant layer on their outer surface.
  3. Most epidermal cells are relatively flat..often their outer and side walls are thicker than the inner wall.
  4. We can observe pores on the epidermis of the leaf. These pores are called stomata
  5. Stomata are enclosed by two kidney shaped cells called guard cells
  6. They are necessary for exchanging gases with the atmosphere.
• In some desert plants, epidermis has a thick waxy coating of cutin. They also have a substance called suberin in their walls that makes them impervious to gases and water.
• Complex permanant tissues

  Xylem

  1. Trancheids
  2. Vessels
  3. Xylem parenchyma
  4. Xylem fibres

  Phloem

  1. Sieve tubes
  2. Companion cells
  3. Phloem parenchyma
  4. Phloem fibres
• Xylem and phloem are the conducting tissues in the plant body. While xylem conducts water and minerals, phloem conducts food materials. Xylem and phloem together constitute the vascular tissues 

  1. Vascular tissues is a distinctive feature of the complex plants
• 1. Xylem consists of tracheids, vessels, xylem parenchyma and xylem fibres  
  2. Tracheids and vessels have which walls and many are dead cells when mature.
  3. Tracheids are vessels and tubular structures. This allows them to transport water and minerals vertically
  4. The parenchyma stores food
  5. Xylem fibres are mainly supportive in function
• 1. Phloem is made up of 5 types of cells: sieve cells, sieve tubes, companion cells, phloem fibres and the phloem parenchyma
  2. Sieve tubes are tubular cells with perforated walls
  3. Phloem transport food from leaves to other parts of the plant.
  4. Except for phloem fibres, other phloem cells are loving cells 
• Animal tissues:

  The four basic types of tissues are found which are as follows:

  1. Epithelium or epithelial tissues (covering tissues)
  2. Connective tissues (supporting tissue)
  3. Muscular tissue (contractile tissues)
  4. Nervous tissue 
• Epithelial tissues

  1. the covering or protective tissues in the animals bodies.
  2. Lies close together with little or no intercellular substance between them.
  3. There is no blood or lymph supply but there is nerve supply is present
  4. Epithelial cells are attached to the underlying tissues by a basement membrane.
  5. Epithelial may be one cell which that is single layered.
• Types of epithelial tissues

  1. Squamous (cells flattened)
  2. Stratified squamous (cells many layered)
  3. Cuboidal (cells cube like)
  4. Columnar (cells tall, column or pillar like)
• Squamous

  1. The cells are extremely thin and flat and are arranged edge to edge forming a delicate lining or covering
  2. It forms the lining of cavities of ducts and blood vessels.
  3. We have chambers of the heart, covers the skin and lining of the mouth and nose
  4. This epithelial tissues is also called a pavement epithelial
• Stratified squamous

  1. These are arranged in many layers, one above the others
  2. Found in places where there is much wear and tear such as the epidermis of skin lining of the mouth cavity, tongue, oesophagus and vagina
  3. Thin walled, flat cells forming a delicate lining found in case squamous.
  4. Helps in transportation of substance through the selectively permeable surface.
• Cuboidal

  1. Cells are as long as broad and appear cube like
  2. A centrally located nucleus is present.
  3. It is found in some parts of kidney tubes, ducts of salivary gland, thyroid gland etc
• Columnar

  1. Forms the lining of stomach and intestines: also found in salivary gland in the mouth, swear glands and oil glands of the skin
  2. Columnar epithelium modified to form glands is called glandular epithelium
  3. Glandular epithelium, this, performs secretory function
• Connective tissues is composed of the cells and numerous, thick structures called fibres.

  The cells of connective tissues are loosely spaced and embedded in an intercellular matrix

  
  

  The matrix may be jelly like, fluid or dense or ridgid.The matrix may be jelly like, fluid or dense or ridgid.

  Different kind of examples are:

  1. Blood
  2. Bone
  3. Cartilage
  4. Areolar
  5. Fat-storing