Q1.
Now think, which tissue helps you move? Which tissue enables you to sense heat or cold? Which tissue allows oxygen to enter the blood? Which tissue holds the body together so that the skin does not fall off?
Answer
Four different questions, four different animal tissues — and in every case the structure of the tissue is the answer.
| Action | Tissue | Why that structure works |
|---|---|---|
| Clench and open your fist | Muscular tissue | Long cylindrical muscle fibres lie parallel and can contract; skeletal muscle is attached to bone by tendons, so its pull becomes movement at a joint |
| Touch something warm or cold | Nervous tissue | Receptors in the skin pass the signal to a neuron; the dendrites receive it and the long axon carries it to the brain within milliseconds |
| Take a deep breath | Epithelial tissue | The lining of the lung and of a blood vessel is a single layer of thin, flat cells, so the diffusion path for O₂ into the blood is as short as it can be |
| Skin stays attached | Connective tissue | Cells embedded in a matrix bind skin to the tissues beneath; the same family of tissues also joins muscle to bone (tendon) and bone to bone (ligament) |
Blinking your eyes uses all four at once — nervous tissue triggers it, muscular tissue moves the eyelid, epithelium covers it, connective tissue holds it in place.
Why animals need four kinds: an animal body has to cover surfaces, hold parts together, move, and coordinate. No single tissue design can do all four, so animal tissues fall into exactly these four groups — epithelial, connective, muscular and nervous.