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Types of celi

Cells come in many different shapes and sizes and have a wide rangę of functions. There are morę than 200 different types in the body. Here are just a few.

Nerve celi (neuron)

Sends out and receives Information from other cells through tiny electrical impulses.

Red blood celi

Picks up oxygen from the lungs and carries it to other body cells. They also give blood its typical red color.

Epithelial celi

Packed together, these protective cells form the skin's epidermis and linę organs, such as the lungs and stornach.

Fat celi

Found in layers under the skin, these cells storę fat as an energy reserve and to insulate the body.

Muscle celi

Contains long strands of fibrous protein that interact to make muscle cells contract, usually when triggered by a nerve signal.

Liver celi

Regulates the Chemical composition of the blood by storing and Processing food and removing harmful substances.

Photoreceptor celi

These light-sensitive cells found in the eye convert light into nerve impulses to send to the brain.

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Chromosomes at center

Microtubule

Remove the membranę around the nucleus, build a framework of microtubules inside the celi, and linę up the duplicated chromosomes in the cell's center.

New nuclear membranę

Cytoplasm

divides

Duplicate celi

Chromosome

Tissue (group of cells with similar characteristics)

Body basics

Celi (the basie unit in all living things)

Organ (collection of tissues that perform a particular function)

System (collection of organs and tissues that carry out an important task)

BONĘ REPAIR

Believe it or not, bones are living organs that contain cells. If you break a bonę, cells called osteoblasts

will build up new bonę and repair the fracture.

WEIRD OR WHAT?

The widest body celi

«the _{female sex}^yoe®«

the ovum, which, with a '^eter of around 0.04 in f

°'tnTh^m)'^isjustvisible ^ to the naked eye.

Form nuclear membranes around both sets of chromosomes and divide the celi cytoplasm.

Nucleus

Congratuiations!

You have successfully completed mitosis, or celi division. Repeat as necessary to grow or replace worn-out cells.

(c) 2011 Dorling Kindersley. All Rights Reserved.

Protein power

^ M Proteins are the w A most varied group of Chemicals in the body.

Their roles include w u building cells and making them work, as well as defending the body against germs.

Proteins consist of w O chains of "building blocks" called amino acids.

(\A DNA inside the cell's w* nucleus contains the instructions for assembling the right amino acids in the correct order to build each type of protein.

^ Each protein has W w a uniąue function. For example, hemoglobin in red blood cells picks up oxygen, releasing it where its needed.

Cells

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