Download Movement and Coordination

Your Skeletal System
The skeletal system has two main
functions: Structure/Support and
Protection
Your bones also store important
minerals, such as calcium and
phosphorus.
The human body is made up of 206
bones. You were actually born with
more than 206 bones in your body.
Where did they disappear to?
To make your study easier,
you can look at the skeleton
in two parts. The Axial and
the Appendicular.
How Many Bones?
 Skull and upper jaw 21 bones
 3 tiny bones in each ear
 Lower jaw (mandible)
 Front neck bone (hyoid)
 Backbone or spine (26 separate bones or vertebrae)
 Ribs (12 pairs - same number for men and women)
 Breastbone
 Each upper limb has 32 bones: 2 in shoulder, 3 in arm, 8 in
wrist, 19 in hand and fingers.
 Each lower limb has 31 bones: 1 in hip (one side of pelvis), 4 in
leg, 7 in ankle, 19 in foot and toes.
Total = 206 bones
The Axial Skeleton
The axial skeleton includes the
bones in your head, your breastbone,
your ribs, and the bones in your
backbone.
Cranium-encloses the brain and
protects it.
Vertebrae-backbone/spinal column
Consists of 26 bones. Supports the
head, gives flexibility to your neck
and back, and helps shield the spinal
cord from injury.
Cartilage-a tough, supportive tissue
that is softer and more flexible than
bone. Makes the backbone flexible
and also absorbs shocks.
The Appendicular Skeleton
The appendicular skeleton includes
the bones in your arms, hands, legs,
feet, hips, and shoulders.
Joint-the point at which two bones
come together.
Ligaments-strong, fibrous bands hold
bones together at moveable joints and
prevent them from popping apart.
Synovial fluid-a secretion produced
by membranes around the joint which
lubricates the joint and reduces wear
on the bones.
Structure of Bones
Bones are complex organs that remain active
even after they stop growing.
All of your bones are covered with a tough
membrane called periosteum which contains
cells that form new bone during growth and
repair. Blood vessels run through the
periosteum and branch into the bone.
Compact bone-very hard and dense
Spongy bone-filled with spaces and acts as a
shock absorber.
Marrow-soft tissue inside bones where blood
is produced. There are two types: red and
yellow.
Most of your blood cells are manufactured in
red marrow. Some bone marrow produces red
blood cells and others produce white cells .
Development of Bone
The skeleton begins development long before birth. A newborn
baby’s skeleton is made mostly of cartilage. Eventually most of this
cartilage is replaced by bone in the process of ossification. During
this process, minerals, such as calcium and phosphorus, are
deposited within the cartilage, making it hard. Ossification began
before you were born and will continue until you are 20 to 25 years
old.
Fracture- a break in the bone.
Incomplete fracture
Complete fracture
Open/Compound fracture
Incomplete
Fracture
A break that does not go all the way across the bone and the pieces of
bone do not separate.
Closed/Complete Fracture
Broken bone
does not
pierce the
skin
Compound/Open Fracture
Bone pierces the skin
and germs can get inside
the body and infect body
tissues, including the
broken bone.
Joint Disorders:
Dislocation, Sprain, Torn cartilage, Bursitis, Arthritis
Dislocation- the ends of the bones are
forced out of their normal positions in a
joint.
Sprain- consists of overstretched or torn
ligaments or tendons. Sprains occur
more frequently than any other joint
injury.
Torn cartilage- damage to the cartilage
that covers the ends of bones in a joint.
Occurs most often among athletes who
participate in sports that involve severe
stress on the knees.
Joint Disorders;
continued
Bursitis is a painful irritation of the bursa
which is a fluid-filled sac that cushions
certain joints and tendons. May be caused
by injury or repeated strenuous activity.
Arthritis-inflammation or irritation of a
joint. One of the most common noninfectious diseases, affecting nearly one
in every seven people in the United
States.
Scoliosis
Scoliosis
An abnormal curvature of the spine.
In this condition, which is more common in
girls than in boys, the vertebrae in the
backbone line up in such a way that the
backbone twists to one side. This condition
can be inherited, it can also result from
certain diseases, including rheumatoid
arthritis and cerebral palsy. Early symptoms
include shoulders that are not level, uneven
hips, and an uneven waistline.
Osteoporosis
As people become older, their
bones begin to lose some of their
calcium. This loss can lead to
osteoporosis, a condition in which
bones become weak and break
easily. Elderly women are more
likely to develop osteoporosis than
are elderly men. Evidence
indicates that regular exercise can
help prevent this disorder. Your
calcium intake now, during
adolescence, can help you avoid
osteoporosis later in life.
Your Muscular System
How Muscles Work
Types of Muscles- different kinds of muscles
perform different functions. You have three
types of muscles in your body: skeletal,
smooth, and cardiac.
Skeletal muscle is voluntary muscle, you
control its movement deliberately.
These muscles are attached to the bones of
your skeleton and enable you to do such things
as run, throw, and eat.
Skeletal muscles are attached to bones by
thick strands of connective tissue called
tendons. Most skeletal muscles work in
pairs, one muscle in the pair moves the bone
in one direction, while the other moves the
bone in the opposite direction.
Smooth and Cardiac Muscles
Smooth Muscle Works automatically to control movements inside your body, such as
those involved in digestion. Smooth muscles in the walls of your
esophagus and intestine push food through your digestive system.
Cardiac Muscle Found only in the heart. Like smooth muscle, it is also involuntary.
Cardiac muscle contracts automatically, over and over, approximately
70 times a minute.
What do you think is the strongest muscle in the body?
Muscle Contraction
All muscles do their work by contracting, or becoming shorter and
thicker. Muscle cells (fibers) contract when they are stimulated by
impulses from the nervous system.
Even when muscles are not moving, some of their fibers are
contracting. Muscle tone is the slight, constant contraction of a muscle
that is due to the contraction of some of its fibers. Muscle tone enables
you to maintain your posture. (Ex. The muscles in your neck may not
contract enough to move your head, but they contract enough to keep
your head upright.)
Muscles use energy when they contract.
Sugar glucose + oxygen(carried in blood) = energy
When a muscle group is highly active, oxygen cannot be supplied fast
enough to the muscle fibers. Lack of oxygen forms a chemical reaction
that produces a substance called lactic acid as a waste product.
Did you know ?
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What are two main functions of the skeletal system?
The human body is made up of _____ bones.
Can you name 4 bones in the human body?
What is the supportive tissue called that is found
between every joint in the body?
What is the name of the tissue that holds two bones
together at a joint?
Can you name the three types of muscles in your
body?
When do your bones stop growing?