MUSCULAR SYSTEM
The muscular system works with the
skeletal system to allow movement of our bodies.
There are 3 types of muscles:
smooth-
involuntary muscles
long, thin, pointed at each end
form into sheets
examples: intestines, stomach
skeletal-
voluntary
joined in bundles
cylinder shaped
cardiac-
involuntary
heart muscle
Muscles receive nerve signals to work.
When a message is sent, a muscle contracts or gets smaller.
When the message stops, the muscle relaxes.
Muscles can pull, contract, and relax. They cannot push.
Muscles can be attached to bones.
Flexor muscles bend body joints. Extensor
muscles straighten body joints. Flexor
and extensor muscles usually work in pairs.
If a movement is not caused by bending
or straightening a body joint, it is called abduction or adduction.
Abduction is when movement away from
the body occurs.
Adduction involves moving toward the
body.
Example: lifting arm straight up and
down from the shoulder
Some muscles are attached to bones by tendons. They are non-elastic and firmly join bones together.
Others are attached by ligaments. They are elastic tissues that attach bone to bone in moveable joints.
Tendons can be compared to leather straps while ligaments can be compared to rubber bands.
