Ch. 2Lesson 2

How do cells work together?

cells

tissues

organs

shape-specialized to fit its job

Group of cells working together doing same job

ex: groups of nerve cells= nerve tissue

Tissues working together

ex: heart, eyes

Examples of cells:

The shape of nerve cells makes them great for communicating signals between the brain and the body.

1. Branching cells

2. Flat cells such as skin cells, often join or overlap to cover a surface.

The smooth shape of red blood cells helps them move easily

through blood vessels to carry oxygen to the body.

3. Round Cells

sickle cell anemiasickle cell anemia

• When a friend whispers in your ear, sound waves cause many parts of your ear to vibrate.

• This causes hair-like structures on cells in your inner ear to bend and send nerve signals to the brain.

4. Muscle cells4. Muscle cells have long fibers made of protein. Many cells work

together in bundles, making the muscle strong.

Quick! What's the

biggest organ in your body?

skin cells• Form in many layers• New cells form push out old

layers• Protects inside of body• Keeps out germs• Regulates water

skin• Contains skin cells, nerve tissue,

blood vessels, oil glands, sweat glands & muscle tissue

• Sweat evaporates-cools you off• Outer layer-made up of dead cells

You are likely to shed 40

pounds of skin in a lifetime.

• Right now there are over a million dust mites, microscopic

critters invisible to the naked eye, on your mattress and pillow,

chomping on the dead skin cells that fell off

you last night!

Tastes like

chicken!

Yummy!

What’s for

dessert?

Name that cellName that cell

Branching cells

Round Cells

Flat cells

Muscle cells

skin cells• Form in many layers• New cells form push out old

layers• Protects inside of body• Keeps out germs• Regulates water