Cells, Tissues and Organs
Tissues
Living things, including animals and plants, are called organisms. There are many different kinds of cell in an animal or a plant. Most of them are specialised to carry out a particular activity. Usually, many cells of the same kind are grouped together.
A group of similar cells, which all work together to carry out a particular function, is called a tissue.
The diagrams show a tissue from a plant, and a tissue from an animal.
This is a diagram of a tissue from inside an onion. It is called an onion epidermis. This tissue covers the surface of the layers inside the onion.
This is a diagram of ciliated epithelium – the tissue that lines the tubes leading down to our lungs. The cilia all wave together, like grass in the wind.
Questions
What is the function of the ciliated epithelium tissue?
(Think about the function of a ciliated cell.)
Show Answer
The function of ciliated epithelium tissue is to move mucus, dust, and bacteria out of the airways. The cilia beat together to push mucus away from the lungs toward the throat.
The word ‘tissue’ has an everyday meaning and a different scientific meaning.
Write two sentences, one using the word ‘tissue’ with its everyday meaning, and one using the word ‘tissue’ with its scientific meaning.
Show Answer
Everyday meaning: I used a tissue to blow my nose.
Scientific meaning: Muscle tissue helps the body move by contracting and relaxing.
Organs and organ systems
The bodies of plants and animals contain many different parts, called organs. For example, your organs include your brain, heart and muscles. Plants’ organs include leaves, roots and flowers.
Each organ is made up of several different kinds of tissue, working together. For example, your brain contains neurones, and also several other kinds of cell. A plant root contains root hair cells, and also several other kinds of cell.
Organs also work together. A set of organs that all work together to carry out the same function is called an organ system.
Questions
Copy and complete each sentence, using words from the list.
organism tissue organ organ system
A group of similar cells is called a ____________.
An ____________ is a structure made of many different tissues.
An ____________ is a group of organs that carry out a particular function.
An ____________ is a living thing. It may contain many different organ systems, organs and tissues.
Show Answer
A group of similar cells is called a tissue.
An organ is a structure made of many different tissues.
An organ system is a group of organs that carry out a particular function.
An organism is a living thing. It may contain many different organ systems, organs and tissues.