B2.2.1 Animal organs (part 1)
Large multicellular organisms develop systems for exchanging materials. During the development of a multicellular organism, cells differentiate so that they can perform different functions.
A tissue is a group of cells with similar structure and function. Examples of tissues include:
- muscular tissue - contracts to bring about movement
- glandular tissue - produces substances such as enzymes and hormones
- epithelial tissue - covers some parts of the body.
Organs are made of tissues. One organ may contain several tissues. The stomach is an organ that contains:
- muscular tissue - churns the contents
- glandular tissue - produces digestive juices
- epithelial tissue- cover the outside and the inside of the stomach.
B2.2.1 Animal organs (part 2)
Organ systems are groups of organs that perform a particular function. The digestive system is one example of this. The digestive system includes:
- glands - produces digestive juices (e.g. pancreas and salivary glands)
- the stomach and small intestine - digestion occurs
- the liver - produces bile
- the small intestine - where the absorption of soluble food occurs
- the large intestine - where water is absorbed from the undigested food, producing faeces.
B2.2.2 Plant organs
Plant organs include stems, roots and leaves.
Examples of plant tissues include:
- epidermal tissues - cover the plant
- mesophyll - carries out photosynthesis
- xylem and phloem - transport substances around the plant.