Chapter 6: Tissues
6.1 What is a Tissue?
A group of cells that are similar in structure and/or work together to achieve a particular function forms a tissue. Multi-cellular organisms show division of labour through tissues.
6.2 Plant Tissues
Meristematic Tissue
Dividing tissues found in growing regions. Classified into: Apical (tips), Lateral (girth), and Intercalary (nodes).
Simple Permanent
- Parenchyma: Living cells, stores food.
- Collenchyma: Provides flexibility.
- Sclerenchyma: Makes plant hard (e.g., coconut husk).
Complex Permanent
- Xylem: Transports water/minerals vertically. Consists of tracheids, vessels.
- Phloem: Transports food. Consists of sieve tubes, companion cells.
6.3 Animal Tissues
Categorized into four main types:
| Type | Structure/Function | Location |
|---|---|---|
| Epithelial | Protective covering, tightly packed. | Skin, blood vessels. |
| Connective | Loosely spaced, links organs. | Blood, Bone, Cartilage. |
| Muscular | Contractile proteins for movement. | Skeletal, Smooth, Cardiac. |
| Nervous | Rapid response to stimuli. | Brain, Spinal cord, Nerves. |
Focus: Neuron
The unit of nervous tissue. Consists of a cell body with a nucleus, an axon (long part), and dendrites (short hair-like parts).
Key Differences
Plants: Stationary, most tissue is supportive/dead, growth limited to regions.
Animals: Mobile, most tissue is living, growth is uniform throughout.