Tissue Class 9 Notes – A summary and revision notes for Class 9 Science Chapter 6, Tissues, are provided here. The entire chapter’s major points, revision comments, pictures, and diagrams are included in the notes. Students studying science with the NCERT Textbook and looking for a quick approach to learn the crucial facts will find these notes useful.
Tissue Class 9 Notes
Tissues
The tissues are collections of related cells that serve a single purpose.
Plant Tissues
Plant tissues is a groups of cells with a similar shape and function. There are two main types of plant tissues.
a) Meristematic Tissues
b) Permanent Tissues
a) Meristematic Tissues
Plant tissues that are undergoing development and have the capacity to divide and produce new cells are called meristematic tissues. They are in charge of a plant’s growth and development at the tips of roots and shoots. Meristematic tissues can be divided into three types –
- Apical meristem
- Intercalary meristem
- Lateral meristem
- Apical meristem – The apical meristem is a region of actively dividing cells located at the tip of the stem and roots of a plant. It is responsible for the continuous growth of the plant by elongating the stem and increasing the length of roots.
- Intercalary meristem – In general, grasses exhibit intercalary meristem growth, which takes place close to the bases of leaves and stems.
- Lateral meristem – In woody plants, such as trees and shrubs, there is a form of meristematic tissue called lateral meristem that aids in the development and thickening of stems and roots.
b) Permanent tissues
When cells decide not to develop and divide but focus on serving a certain purpose inside the plant that type of tissue is known as permanent tissues. There are two types of permanent tissues –
- Simple permanent tissue
- Complex permanent tissue
1. Simple permanent tissue – Simple permanent tissues are made up of only one type of cell and perform a single function within the plant. Simple permanent tissues come in three different types parenchyma, collenchyma, and sclerenchyma.
- Parenchyma – Parenchyma cells are plant cells that are typically found in the ground tissues of plants. They are characterized by their ability to perform metabolic functions and to store reserve materials such as starch, oils, and proteins. They are typically thin-walled and have a large central vacuole that helps to maintain the turgor pressure of the cell.
- Collenchyma – Collenchyma cells are a type of plant cell that provide structural support to the plant. They are usually found in young, growing parts of the plant, such as stems and leaves, and are characterized by their thickened cell walls.
- Sclerenchyma – Sclerenchyma cells are dead cells with thick walls that provide support to the plant in various parts such as seeds, nuts, and fibers.
2. Complex permanent tissue – Complex permanent tissues are made up of different cells that collaborate to perform a specific task within the plant. Complex permanent tissue comes in two different types.
- Xylem – Water and minerals are moved from the roots to the rest of the plant by xylem tissue. It is made up of a variety of cell types, including tracheids and vessel components, which combine to produce a continuous channel for the movement of water and minerals.
- Phloem – Phloem tissue, on the other hand, is responsible for transporting sugars and other organic nutrients from the leaves to the rest of the plant. It is composed of several cell types, including sieve tube elements and companion cells, that work together to form a continuous pathway for sugar transport.
Animal tissues
Animal tissues are collections of similar cells that work together to perform specific functions within an organism. The four primary categories of animal tissues are as follows.
- Epithelial tissue
- Connective tissue
- Muscle tissue
- Nervous tissue
Epithelial tissue – Epithelial tissues are a type of animal tissue that covers the surface of the body and lines internal organs and glands. They are made up of cells that are closely packed together and provide a barrier between the internal environment of the body and the external environment. There are three main types of epithelial tissue squamous, cuboidal, columnar, Ciliated and Glandular tissue.
- Squamous epithelial tissue – Cells that are found in areas where diffusion and filtration are important, such as the lining of the blood vessels and the alveoli in the lungs.
- Cuboidal epithelial tissue – is composed of cube-shaped cells that are found in areas where secretion and absorption occur, such as the tubules of the kidneys and the lining of glands.
- Columnar epithelial tissue – is composed of tall, narrow cells that are found in areas where absorption and secretion occur, such as the lining of the small intestine and the stomach. Some columnar epithelial tissues have finger-like projections called microvilli that increase the surface area for absorption.
- Ciliated epithelial tissue – Those epithelial tissues which contains cilia that is hair like projections are called as ciliated epithelial tissue.
- Glandular epithelial tissue – those epithelial tissues present on the linings of different glands are called as glandular epithelial tissues.
Connective tissue – gives the body assistance and defence. The body’s connective tissues, which include bones, tendons, ligaments, and cartilage, are the most prevalent and extensively dispersed types of tissue.
- Connective tissue Proper
- Areolar tissue – located in the skin, muscles, and areas around blood vessels, nerves, etc. It acts as a cushion and support for the body’s organs and tissues.
- Adipose tissue – This type of tissue stores energy as fat and is found between internal organs and under the skin, providing insulation for the body.
- Fibrous Tissue – Ligament and Tendon
- Connective tissue Dense/ Supportive
- Dense regular connective tissue – This type of tissue is mainly composed of to bones and cartilage, providing stability to the body’s joints.
- Skeletal tissue – Cartilage and bone are the main components of skeletal tissue, which provide structural support and protection for the body.
- Fluid tissue –
(1) Blood is a fluid tissue present in animals and functions as a transport system for oxygen, nutrients, and waste products throughout the body.
(2) Lymph – The fluid surrounding the body cells which contain WBC, present throughout the body whose function is protection against disease.
Muscular tissue – is a type of tissue that is responsible for movement and the generation of force. Muscular tissue comes in three primary categories:
- Skeletal muscle tissue/Striated /striped/Voluntary – Attached to bones and is responsible for voluntary movements, such as walking, running, and lifting.
- Smooth muscle tissue/ Non striated/Non striped/Involuntary – Found in the walls of organs, such as the esophagus, stomach, and intestines. It is responsible for involuntary movements, such as pushing food through the digestive system.
- Cardiac muscle tissue/Heart muscle Tissue – Found besides the heart and is responsible for pumping blood throughout the body. It is involuntary, meaning that it shows rhythmic contraction and relaxation automatically.
Nervous tissue – Information is transmitted and processed by nervous tissue, a type of tissue found throughout the body. Neurons and glial cells make up its two main cell types.
- Neurons – Specialized cells called neurons are in charge of carrying electrical impulse (messages) throughout the body.
- Glial cells – They help to maintain the proper functioning of the nervous system by providing insulation for neurons, removing waste, and helping to repair damaged neurons.
- Parts of Neuron – Dendrite , cell body which contains nucleus ,axon, Myelin sheath ,nerve ending (axonal ending)
- Synapse :- The point of contact (junction) between axonal end of one neuron and the Dendrite of other neuron is called synapse where in the messages are transmitted by the chemical signals.