2.1.1 principles of organisation

What are cells?

Cells make up all living things.

What is a tissue?

A tissue is a group of specialised cells with a similar structure and function.

Can a tissue be made of more than one type of cell?

Yes, tissues can be made of more than one type of cell, e.g. muscular tissue or epithelial tissue.

What is an organ?

An organ is formed from a number of different tissues working together to produce a specific function.

Give an example of an organ and its tissues.

The stomach is an organ that contains muscular tissue and epithelial tissue.

What is an organ system?

An organ system is a group of organs working together to perform a certain function.

Give an example of an organ system.

The stomach, liver and small intestine are part of the digestive system, which digests food.

How do cells, tissues, organs and organ systems relate?

Cells form tissues, tissues form organs, and organs form organ systems.