Transcript Muscular & Skeletal Systems

Muscular & Skeletal Systems
a.k.a. The Musculoskeletal System
The Skeletal System
Bones
 Provide support for the body
 Form the body’s shape
 Very lightweight, but strong
enough to support body
weight
 206 bones in the body
Inside a Bone
 Compact bone – the solid,
hard outside part of the bone
 Cancellous bone – spongy,
inside the compact bone
 Bone marrow – inside of
the bone; where most of the
blood cells are made (make a
connection to another system)
Between the Bones
 Ligaments – long, fibrous
straps that connect bones
to other bones
 Cartilage – flexible,
rubbery substance;
supports bones and
protects them when they
rub against each other
Types of Bones
 Short bones – chunky, wide bones; feet and wrists
 Long bones – a bone that is significantly longer than it is
wide; arm and leg bones
 Flat bones – plate-like bones, have a flat shape; ribs and
shoulder blades
 Irregular bones – have odd shapes and don’t fit into any
other category, vertebrae
The Muscular System
Muscles
 Muscles pulls on the joints,
allowing us to move
 Help the body perform other
functions necessary for life,
such as digesting food (make
another connection here)
 More than 650 muscles – half
of a person’s body weight
 3 types of muscle…
Skeletal Muscle
 attached to bone, mostly in the
legs, arms, abdomen, chest, neck,
and face
 Striated muscles (made up of
fibers that have horizontal stripes)
 Hold the skeleton together, give
the body shape and help it with
everyday movements
 Voluntary (you can control their
movements)
Smooth Muscle
 Found in the stomach and small
intestines; blood vessels (more
connections here)
 Looks smooth, not striated
 Involuntary (you don’t control
the movements, they are
controlled by the nervous
system automatically)
Cardiac Muscle
 Found in the heart
 walls of the heart's chambers
are composed almost
entirely of muscle fibers
 Involuntary (you don’t
control the movements, they
are controlled by the
nervous system
automatically)
Joints
 Allow our bodies to move in many ways
 Classified by their range of movement (3 types)
 Immovable (fibrous) joints don’t move
 dome of the skull
 Teeth in the jaw bone
 Partially movable (cartilaginous) joints move a little
 Spine (linked by cartilage)
Freely movable (synovial) joints
 Move in many directions
 Filled with synovial fluid
 Hinge joints move in one direction
 Elbow, knee
 Pivot joints allow a rotating or
twisting motion
 Neck, wrist
 Ball-and-socket joints allow the
greatest freedom of movement
 Hip, shoulder
Movement
 Tendons – connects bones to the
skeletal muscles
 Muscle cells – only cells in the
body that can shorten (contract)
 Flexor – muscle that causes a
joint to bend when it contracts
 Extensor – muscle that causes a
joint to straighten when it
contracts
For more information check out…
 http://kidshealth.org/teen/y
our_body/body_basics/bones
_muscles_joints.html#