CONTENT LIST
Tissue
- A group of cells that have common origin, similar structure and perform a definite function in multicellular organisms is called a tissue.
- They form a cellular organizational level, intermediate between the cells and organ system.
- Organs are made up by combining the functional groups called tissues.
- Multicellular organisms like plants and animals have division of labor because a particular function is carried out by a group of cells termed as tissues at a definite place in the body.
Are plant and animal are made up of same kind of tissue?
- The plant and animal tissue are different from each other in their composition as well as functioning.
- Plants tend to grow throughout their life, whereas animals grow up to a certain period.
- Plants do not show locomotion but animals show locomotion.
- Plant tissues have cell walls made of cellulose while animal tissues have a membrane made of protein.
- Plant tissue comprises both living and non-living cells; therefore, the energy demand of plant tissue is less. Whereas animal tissue comprises living cells; therefore, animal tissues require more energy.
- Plant tissue provides the structural support while animal tissue aids in the locomotion.
Plant Tissue
- A plant tissue is a group of cells that is specialized to perform a specific function inside the plant body.
- The plant cells are made up of cellulose cell wall as well as several vacuoles.
- They contain chlorophyll-like photosynthetic pigments to produce simple sugars inside the cells.
- A plant is an immobile organism so most of the plant cells are involved in providing the structural support to the plant.
Plant tissues can be grouped into two categories based on the organization of the cells:
- Meristematic Tissue
- Permanent Tissue
Meristematic tissue
- The meristematic tissue is capable of dividing throughout the life of a plant . It is called growth tissue.
- meristematic tissue helps the plants to grow in both length and width.
- In order to create specialized structures like the buds of leaves and flowers, the terminals of roots and shoots, etc., the cells of the meristematic tissue actively divide.
- Plants grow only in those regions where meristematic tissues are present.
- The three types of meristematic tissue in the plant are the apical meristem, intercalary meristem, and the lateral meristem.
- Apical Meristem: It is present at the growing tips of stems and roots.
- Intercalary Meristem :It is present at the base of the leaves or internodes of twigs.
- Lateral Meristem : It is present on the lateral sides of stems and roots.
Permanent Tissue
- Permanent tissues are fully developed and have lost the capacity to divide.
- These are formed by the division and differentiation of the meristematic tissues.
- The rate of metabolism process in the cells of the permanent tissue is relatively slower.
- Permanent tissue in plants primarily aids in support, protection, photosynthesis, and the conduction of water, minerals, and nutrients.
- Cells in permanent tissue are alive or dead.
There are two types of permanent tissue.
Simple permanent tissue
- Simple permanent tissues are made up of only one type of cells.
- The cells forming these tissues are similar in structure and functions.
Simple Permanent Tissues are further divided into three types
- Parenchyma
- Collenchyma
- Sclerenchyma
Parenchyma
- Parenchyma is the most common simple permanent tissue.
- It is a living, polygonal cell with a large central vacuole, and have large intercellular spaces between them.
- They store food and provide temporary support to the plant.
- They are mostly oval or round in shape& loosly packed.
- It is located in the soft areas of stem, root and leaves.
- It carry out vital life functions such as healing plant wounds, growth, photosynthesis, starch storage, and structural support.
- In some situations, it contains chlorophyll and performs photosynthesis, and then it is called chlorenchyma.
- In aquatic plants, large air cavities are present in parenchyma which help them to float. Such type of parenchyma is called aerenchyma.
Collenchyma
- Collenchyma cells are living cells.These are made of strong, thick cellulose strands twisted around each other and cemented together.
- Another type of permanent tissue that allows flexibility in plants is called collenchyma. It allows bending of various parts of a plant like tendrils and stems of climbers without breaking.
- It also provides a protective layer for plants that contain water-holding cells called hydrochomes.
- Collenchyma cells are found on the outside of roots and stems part of plant.
Sclerenchyma
- Sclerenchyma is a kind of cellular tissue that results from dying parenchyma cells.
- The main function of sclerenchyma is to provide support and strength to the plants.
- The fibres of jute, cotton, hemp and husk of coconut etc. are made up of sclerenchyma tissue.
Complex permanent tissue
- Complex permanent tissues have more than one type of cells having a common origin.
- They have different appearances and they all co-ordinate to perform a common function.
- The Transportation system of plant is made up of complex permanent tissues.
Complex permanent tissues are of two types.
- Xylem
- Phloem
Animal Tissues
- Epithelial tissue
- Connective tissue
- Muscular tissue
- Nervous tissue
- Epithelial tissue form the covering of the external surfaces, internal cavities and organs of the animal body.
- It act as a barrier that keeps different body systems separate.
- The skin, lung alveoli, the lining of the blood vessels, the lining of the mouth, and kidney tubules made up of epithelial tissue.
- Epithelial tissue cells are tightly packed tissues and work as a continuous sheet. They have a small amount of cementing material filled between them and almost no intercellular spaces.
- Anything that enters or leaves the body has to cross at least one layer of epithelium.
- Connective tissues support and connect different tissues or organs of the body like Bone to bone, Muscle to bone or tissue .
- It is made up of a few cells present in the intercellular framework of protein fibres secreted by the cells, known as collagen or elastin.
- These fibre helps connective tissue for elasticity, flexibility and strength .
- Examples of connective tissue are blood (plasma), bones, Cartilage. ligaments and tendons etc
- It also provides the structural framework and mechanical support to different tissues.
Based on the functions animal tissues are four types:
Epithelial tissue
Connective tissue
Diffrent type of connective tissue:
Blood (Plasma):
- The fluid matrix of blood is called plasma.
- It is a yellowish liquid like material.
Plasma contains three types of blood cells suspended in it.
- RBC - Red blood cells
- WBC - White blood Cells
- Platelets
Bones:
- Bone is also a connective tissue which forms the framework that supports the body.
- It is a strong and nonflexible tissue.
- Cells in bones are embedded in a hard matrix that is composed of calcium and phosphorus compounds.
Ligaments:
- Ligament is connective tissue that connect two bones .
- It is flexible or elastic in nature.
Ligaments:
- Bones are connected to muscles by another type of connective tissue named as Tendons.
- Tendons are fibrous tissue with great strength but limited flexibility.
Cartilage:
- Cartilage is another type of connective tissue which has widely spaced cells. The solid matrix of this tissue is composed of proteins and sugars.
- Cartilage smoothens bone surfaces at joints and is also present in the nose, ear, trachea and larynx.
- Cartilage of ear can be folded.
Types of connective tissue:
- Areolar tissue: This kind of tissues are found in the skin and muscles, around the blood vessels, nerves, etc & have function to fill the space inside the organs, supports internal organs and helps in repair of tissues.
- Adipose tissues: These are found between the internal organs and below the skin & have function to stores fats & act as insulator
Nervous tissue
- Cells of the nervous tissue are highly specialised . It is being stimulated and then transmitting the stimulus very rapidly from one place to another within the body and finally to brain.
- The brain, spinal cord and nerves are all composed of the nervous tissue.
- Nervous tissue are called neurons.
Muscular tissue
- Muscular tissue tissue is responsible for movement in our body.
- It consists of elongated cells, also called muscle fibres.
- It provide movement to the body.
- Muscles Tissue contain special proteins called contractile proteins, that contract and relax results movement.
Types of muscular tissue
- Striated muscles or skeletal muscles or voluntary muscles:
- Smooth muscles or involuntary muscles:
- Cardiac muscles or involuntary muscles:
Striated muscles or skeletal muscles or voluntary muscles:
- These kind of muscles are also called skeletal muscles because they are mostly attached to bones and help in body movement.
- Cells of Striated muscles are cylindrical, unbranched and multinucleate.
Smooth muscles or involuntary muscles:
- Smooth muscles are found in the iris of the eye, in ureters and in the bronchi of the lungs.
- Cells of Smooth muscles are long, spindle-shaped and possess a single nucleus.
Cardiac muscles or involuntary muscles:
- Cardiac muscles help in rhythmic contraction and relaxation of the heart.
- Cells of Cardiac muscles are cylindrical, branched and uninucleate.
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