Chapter 10: Movement
and Forces
10.1 The skeletal system provides movement and protection
10.2 The muscular system makes movement possible
10.3 Muscles exert forces
10.4 Bones and joints at as levers
The skeleton is the body’s framework
• Skeletal system
• includes bones, ligaments, cartilage, and tendons
• anchors the body’s movement, provides support, and
protects the internal organs
The skeleton is the body’s framework
• Bones: are classified by their
shape:
• Long bones
• longer than wide
• Found in the arms and legs
• Short bones
• As long as wide
• Bones in the wrists and ankles
• Flat bones
• Thin and flat or slightly curved
• Ribcage and skull
• Irregular bones
• Shaped differently than long, short,
or flat
• Spine and skull
The skeleton is the body’s framework
• Skeleton
• Provides the body’s shape
• Works with other systems to allow movement
• Two main divisions:
• Axial skeleton (& Appendicular skeleton)
• central part
• Includes skull, spinal column, ribs
• The bones in the appendicular skeleton are attached to the axial
skeleton
•
What functions do vertebrae perform?
•
They protect the spinal cord and support the
cranium and other bones.
•
How many bones are in the ankle and foot?
•
26
•
Which division of the skeleton includes the
ankle and foot bones?
•
Appendicular skeleton
•
What is the only bone in the skull that can
move?
•
lower jaw
Divisions of the Skeleton Axial Skeleton
• Line straight down your back ~ axis
• Sit, stand, twist…about your axis
• Axis ~ axial skeleton
• Support and protection
• Top: cranium – surrounds the brain
• Cranium + bones in face (jaw, cheek…) = skull
• Skull connects to the spinal column
• Spinal column (backbone): main portion of axial skeleton
• Made of vertebrae – bones stacked one on top of another
• Rib bones and sternum
Divisions of the Skeleton –
Appendicular skeleton
• Bones that function to allow movement
• Arms and legs
• Upper part:
• bones of the shoulders, arms, and hand
• Lower part:
• Bones in hips, legs, and feet
• Bear all the body’s weight while standing
• Leg bones: strongest in your body
Bones are living tissue
• Not solid – have spaces inside –
lighter in weight
• Made of cells and minerals
• Contain blood vessels
• Make, maintains, and break down
bone tissue
• Minerals (ex: calcium) give bones
structure and stiffness
• Bones:
• support and protect the body
• produce and store blood cells
• store calcium for the body
Bones are living tissue – two
types of tissue
• Spongy bone
• Strong
• Lightweight
• Mineral part looks like a web
• Supports bones like beams support a building
• Can compress slightly
• Near the end of long bones: absorb forces
• Red bone marrow: produces blood cells
• New blood cells travel from marrow  blood vessels in bone
• Blood brings nutrients to bone cells / carries away waste
• Compact bone
• Tough outer layer, surrounds spongy bone
• Basic supportive tissue
• Dense, organized in layers - STRONG
•
Why is the compact bone able to give the bone strength?
•
It is dense.
•
How does bone receive nourishment?
•
Blood vessels bring in nutrients.
•
Where are red blood cells formed?
•
in the red bone marrow
Joints connect parts of the
skeletal system
• Joint: a place where two bones in the skeletal system
meet
• allow the body to be flexible
• Three types: immovable, slightly movable, and freely
movable
Immovable and Slightly
Movable Joints
• Immovable joint
• locks bones together like puzzle pieces
• Skull bones are connected by immovable joints
• Inside the cranium, the joints are called sutures (appear
stitched - no space between)
• Slightly movable joint
• Able to flex a little
• Ex: ribs connected to sternum 
• No space between bone, but bones connected by cartilage,
so can move slightly
• Cartilage: tough but flexible connective tissue
• Ex: outer ear, nose, cushions between vertebrae, shark!
Freely Movable Joints
•
Allow you to bend and move
•
Most of the joints in your body
•
Wrist, knee, elbow
•
Bones are separated by a cavity containing fluid
•
Ligaments (tissue) hold bones together at movable joints
•
Materials between bones (ex: fluid, cartilage) keeps them from rubbing
together
•
Tendons (tissue) connect muscles to bones (but are not part of the joint)
•
These all work together with muscles  movement!
Types of joints (6) – based on type of movement
• Hinge Joint
• Ex: elbow and knee
• Arm movement: angle between upper and lower arm decreases
= angular movement
• Ball-and-Socket Joint
•
•
•
•
Ex: hip and shoulder
Pitchers, swimmers, quarterback, shotput…
Shoulder can rotate in a circle
Rounded part of one bone fits into a cup-shaped part of another
• Pivot Joint
• Ex: elbow, connecting the radius and ulna
• Rotational movement – rotate side to side (turn a doorknob)
Types of joints (6) – based on type of movement
•
Gliding Joint
• Ex: some joints in ankles and wrists, vertebrae
• Small flat bones sliding or gliding over one another
• Limited movement
•
Saddle Joint
• ONE ex: thumb
• Like a joystick – forward and backward, side to side
• More limited than ball-and-socket joint
•
Ellipsoid Joint
• Ex: in hands and feet at base of each finger and toe
• Allow bones to move like a hinge in different directions, but not rotate
Different joints work together
 different movements!
• Each motion had a limited
range of movement. The
types and ranges of
movement differed.
• Different joints allow
rotational movements,
angular movements, and
gliding movements.
inflamed, making it harder for muscles
and tendons to slide over bones.
Movement is often painful. Bursitis can
occur when people repeat the same
motion over and over again. Tennis
elbow is one form of bursitis. Bursitis can
also result from heavy pressure on a joint.
Resting the joint and applying ice may
help reduce the inflammation.
Teacher Demo
Do the following demonstration to show
how important cartilage and synovial
fluid, a kind of lubricant, are to making
joints work smoothly. The cartilage and
fluid reduce friction and wear on the
bones. Ask students to watch as you
press and slide a wooden block that has
been sanded—not varnished or polished—
along a flat wooden board. You
will feel friction along the way. Next,
wrap both the board and block in plastic
bags. The plastic acts like cartilage as you
rub the two pieces of wood together.
Now, rub cooking oil on the plastic bags
and run the block along the board. The
How does position affect
support?
• PROCEDURE
1.
2.
3.
Hold the bag in your hand and keep your arm
straight. Move the bag up and down.
Move the handles of the bag over your elbow.
Again hold your arm straight and move the bag
up and down.
Move the bag to the upper part of your arm
and repeat the procedure.
• WHAT DO YOU THINK?
• At which position was it easiest to move the bag?
• At which position did the bag move the farthest?
• nearest to the shoulder
• in the hand