Question

Write a summary on tissues?

Answer 1

Tissues:

1. Group of cells that have a similar structure and perform function together.
2. It is a level of organization in the multicellular organization.

A) Plant tissues:

Plant tissues are of various types:

i) Phloem

1. Made up of sieve tubes, companion cells, phloem parenchyma, and phloem fibers.
2. Conducts food in both directions.

ii) Xylem

1. Made up of vessels and tracheids (conduct water and minerals)
2. Xylem parenchyma (helps in food storage) and xylem fibers (provides mechanical support).

iii) Sclerenchyma tissues

1. Made up of the hard and stiff part of the plant.
2. It is mainly found in the cortex of stems and in leaves.
3. Thickened wall due to presence of lignin.

iv) Meristematic tissues

1. Made up of rapidly dividing cells.
2. It is found in the apices of the root systems and the shoots.
3. Growing tissues of the plant.

v) Permanent tissues

1. Made up of either living or dead cells.
2. Arise from meristematic tissue.

B) Animal tissues:

1. Animal tissues do not have a cell wall and are not rigid.

They are of the following types:

1. Epithelial tissues: Form the outermost protective layer of animals.
2. Connective tissues: Connecting different parts of the body.
3. Muscular tissues: Responsible for all the body movements.
4. Nervous tissues: Responsible for all sensations, consciousness, memory, and emotion.