Key Points

A tissue is a group of cells that are similar in structure and work together to achieve a particular function. Blood, phloem, and muscle are examples.

Tissues enable a division of labour in multicellular organisms. This specialization allows different cell groups to perform specific functions with high efficiency.

Plants are stationary and have more dead, supportive tissues for structural strength. Animals are mobile, consume more energy, and have mostly living tissues.

Meristematic tissue consists of actively dividing cells found in the growing regions of plants. It is responsible for growth in length (apical) and girth (lateral).

Permanent tissues form when meristematic cells lose their ability to divide. This process of taking a permanent shape, size, and function is called differentiation.

Simple tissues are made of one cell type. Parenchyma stores food, Collenchyma provides flexibility, and Sclerenchyma provides hardness and support with dead, lignified cells.

Complex tissues consist of multiple cell types. Xylem conducts water and minerals, while Phloem transports food from leaves to other parts of the plant.

Xylem is made of tracheids, vessels, xylem parenchyma, and fibres. Phloem is made of sieve tubes, companion cells, phloem parenchyma, and fibres.

The Epidermis is the outer protective layer containing stomata for gas exchange. In older stems, Cork forms a protective layer with dead cells containing suberin.

Epithelial tissue is the covering or protective tissue in animals. It forms a continuous sheet covering organs, cavities, and the skin, regulating material exchange.

Connective tissue connects and supports other body parts. Its cells are loosely embedded in an intercellular matrix, which can be fluid (blood) or rigid (bone).

Key types include blood, bone, cartilage, ligaments (connect bone to bone), tendons (connect muscle to bone), areolar tissue, and adipose tissue (stores fat).

Muscular tissue consists of elongated cells called muscle fibres which contain contractile proteins. Their contraction and relaxation are responsible for movement in our body.

Striated (skeletal) muscles are voluntary. Smooth muscles are involuntary and found in internal organs. Cardiac muscles are involuntary and found only in the heart.

Cardiac muscle cells are cylindrical, branched, and uninucleate. They show rhythmic, lifelong contraction and relaxation without getting fatigued.

Nervous tissue is highly specialized for transmitting stimuli. Its basic unit, the neuron, consists of a cell body, dendrites, and an axon to conduct nerve impulses.