Biology Notes on Plant and Animal Tissues
These Tissues are a group of actively dividing cells, which remain in continuous state of division throughout their life.
These are the tissues made up of non-dividing mature cells. Meristematic Tissues when lose the ability to divide(cell-division) transform to permanent tissues. The permanent tissue may be dead or living, thick or thin cellular wall.
This tissues found at the surface of the root, steam and leaves. It is made up of thick cell that protect underlying tissues in plant body.
These tissues made up of similar type of cells, which have common origin and function.The main work of these type of tissue is to provide support to the plant. these are mainly three –
Parenchyma :- These tissues are made up of large and thin cell wall. cells, equally expand on all sides with intercellular space among them, which allows the exchange of gases.
Collenchyma :- These are the tissues made up of living cell which are elongated and the cell wall is thickened at the corners. It is the basically a mechanicnical tissue which provides mechanical support and elasticity to the plants. It is found in outer region of cortex. eg- angles of stems, midrib of leaves, etc.
Sclerenchyma :- These tissues composed of long, narrow cells which have became dead. Cell wall of such cell are greatly thickened due to lignin or cellulose or both. It gives mechanical strength, support and rigidity to the plant body. These are found in the components of hard coating of several seeds and nuts, eg- husk of a coconut.
These are the permanent tissue, composed of more than one type of cell working together. These are mainly two types –
Xylem :- Xylem consists of dead cell hollow cell(wood) in the form of fibers and sclereids, cell are elongated and thick-walled. Its main function is to provide mechanical strength and rigidity to the plant. It is the chief conducting tissue of vascular plants responsible for the conduction of water and dissolved material from roots to the apical part of the plant.
Annular rings formed in tree are made up if xylem. Number of rings indicate the age of the Tree.
Phloem :- It is the chief conducting tissue of vascular plants. They provide a passage for the downward movement of manufactured foods in the leaves. Phloem consists of sieve tubes, companion cells, phloem parenchyma and phloem fibres.
Animal tissues consist of similar cell of common embryonic origin and function. All animals consist of four basic type of tissues. They are –
It is composed of one or more layers of closely packed cells covering the external surface of the body and lining of the body organ including blood vessels. eg- skin, lining of mouth, lining of blood vessels, kidney tubules, etc.
These tissues link and support other tissues or organ of the body. These are most abundant and widely distributed in the body of complex animals. The cells of connective tissues are loosely packed, living, embedded in an intercellular matrix. The matrix may be jelly-like fluid, dense or rigid nature.
Muscle Cells are made up of myocytes which can shorten considerably and return to the original relaxed state. Structurally, they consist of long, narrow cells called muscle fibers and the cytoplasm which is known as sarcoplasm.
The cell of this tissue are long, cylindrical, unbranded having multi nucleate. They have light deep coloured stripes on their outer surface therefore this muscle tissues is called striped or striated muscle tissue.
The cells of non-striated muscle tissue are thin, long with pin pointed ends and uni nucleated. The non-striated muscles are present in the iris of eye, wall of the internal organs such as alimentary canal, blood vessels, urinary bladder, ureter, etc.
The muscles are mainly confined to the wall of the heart. The muscle cells of the heart are cylindrical, branched and uni nucleate. It is found in the wall of pulmonary veins and superior vena cava. It accounts for the rhythmic contraction of the heart muscle by its own throughout the life. Hence known as Involuntary muscles.
Neural tissues is mainly composed of nerve cells and glial cells. The main function of these tissues are to accommodate the working of almost all organs according to specific requirements. It forms central nervous system (CNS), peripheral nervous system (PNS) and autonomic nervous system (ANS). Organs like brain, spinal cord, nerves, etc are all made up of nervous tissues.