Tissue can be defined as a group of cells with similar shapes and functions are termed as tissues. They form a cellular organizational level, intermediate between the cells and organ system. Organs are then created by combining the functional groups of tissues.
Permanent tissues are tissues wherein the growth process has been ceased. These issues originate from both the primary and the secondary meristematic tissues and possess a definite shape and organization. However, they lack the potential to divide.
Based on their constituent cell, Permanent tissues can be classified into two major types:
- Simple tissue – parenchyma, collenchyma and sclerenchyma
- Complex tissue – xylem and phloem
They are living cells and walled, soft in nature due to the presence of thin-walled cells.
These are characterized by uneven thick-walled living cells. This unevenness in the thickening of the cell walls imparts partially hard giving mechanical support derived essentially from the elongated cells of the ground meristems, procambium sometimes.
They have cells with thickened lignified walls, providing them strength and making them waterproof.
Articles to Explore:
- During deficiency of oxygen in tissues of human beings, pyruvic acid is converted into lactic acid in the (a) cytoplasm (b) chloroplast (c) mitochondria (d) Golgi body
- Choose the correct statement with respect to unicellular organisms: (a) in unicellular organisms, tissues work in co-ordination to perform different functions. (b) unicellular organisms do not require food. (c) unicellular organisms respire and reproduce. (d) all unicellular organisms move by cilia.