Dermal System part 2
Nerve cells also called 
neurons transmit electrical 
message to and from your  
brain. Neuron direct
every thought and sensation.
Muscle cells make movement
possible. They are the only
cells that can contract or become
shorter and thicker. In addition,
the hard outer layer of your bones
is made up of bone cells packed 
tightly together into rings it looks 
like a trunk tree. This makes
the bones layer very strong.
White blood cells are mostly
formed in the bone marrow They
attack the germs that makes you sick.