The Skeletal System
The Construction of the Skeletal
System
How is your skeletal system built? What is
it designed to do?
Just like a house, the human
body…
~has framework that is
strong, sturdy, and
connected
~protects what is inside
~stores material
Interesting Facts about the Skeletal
System
• Do we have more bones when we are a baby or when we are all grown up?
Baby has 305 bones and an adult has 206 bones. This is because as we grown some
of our bones join together to form one bone.
• The longest bone in our bodies is the femur (thigh bone).
• The smallest bone is the stirrup bone inside the ear.
• Each hand has 26 bones in it.
• Our nose and ears are not made of bone; they are made of cartilage, a flexible
substance that is not as hard as bone.
Differences between males and females: Males and females have slightly different
skeletons, including a different elbow angle. Males have slightly thicker and longer legs
and arms; females have a wider pelvis and a larger space within the pelvis, through
which babies travel when they are born.
Your skeleton is alive; and
contains major organs like bones,
cartilage, and special structures
that connect them.
1. Cartilage- most bones start off as this soft
flexible tissue and later turn to bone.
2. The place where two bones connect is called
a joint.
3. Joints are kept together with strong elastic
bands of connective tissue called ligaments.
Cartilage
Joint
The Skeletal System
Section 36-1
Skull
Axial
Skeleton
Clavicle
Sternum
Ribs
Vertebral
column
Scapula
Humerus
Radius
Pelvis
Ulna
Carpals
Metacarpals
Phalanges
Femur
Patella
Fibula
Tibia
Tarsals
Metatarsals
Phalanges
Appendicular
Skeleton
Major Functions
1. Protection of vital
organs
a.The ribs shield
important organs such
as your heart and
lungs.
Major Functions
b.Your spinal cord is
protected by the
vertebrae
c.The skull
protects the
brain
AS YOU CAN SEE… OTHER
SYSTEMS RELY ON THE
PROTECTION OF THE SKELETAL
SYSTEM.
Allows for
growth
2. Storage of minerals like calcium
and phosphorous that help
other body systems function
properly and storage of fats for
energy
•
3. Movement – bones work with
muscles to produce movement
Movement
• Skeletal muscles pull on the bones to produce
movement.
– Tendons connect bone to muscle
4. Blood Cell Formation
–Red marrow found in spongy bone produces red blood cells.
Bones are composed of 3 types of
tissues
1. compact bone – no open
spaces
2. spongy bone – open
spaces
3. marrow – 2 types; red
and yellow
i. red – produces red
blood cells
ii. yellow – stores fat
3 Types of Joints
1. Gliding joints allow
bones to glide over one
another.
2. Ball-and-socket joints
Allow bones to rotate
and move freely in all
directions.
3. Hinge joints acts like a
hinge of a door and
allows movement in one
direction
Bones in the
hands
Hip or shoulder
The elbow
Ball &
Socket
Ball &
Socket
Hinge
Ball &
Socket
Hinge
Gliding
Conditions of the Skeletal
System
Osteoporosis
Bones become fragile and more likely
to break
Osteoarthritis
Joint disorder where the cartilage is
wearing away
Conditions of the Skeletal
System
Scoliosis
Abnormal curvature of the spine
Fractures
A break in the continuity of the bone
Open Fracture
a fracture that protrudes to the exterior of the body.
Closed Fracture
A Fracture that does not break the skin
Greenstick Fracture
Only one side of the bone is broken, mostly seen in children
Transverse Fracture
Break at a right angle and caused by direct traumatic injury
Spiral Fracture
Bone broke because of a twisting type motion.
Oblique Fracture
Rarest form of fractures, the break is at an angle.
Assessment Techniques
1. X-rays – radiation absorbed by the body to
make an image
2. Bone marrow aspiration and biopsy – bone marrow
is removed from the body and viewed under a
microscope to detect cancer.
CAT scan (Computed axial tomography) – X-ray
images taken in “slices” to produce 3-d images
MRI (Magnetic resonance imaging) - uses a
magnetic field and pulses of radio wave energy
to make pictures of organs and other soft tissues
The Muscular System
Did you know that ?
- more than 50% of body weight
is muscle !
- And muscle is made up of
proteins and water
Info About Muscles
• Only body tissue able
to contract
• create movement by
flexing and
extending joints
• Body energy
converters (many
muscle cells contain
many mitochondria)
Major Organs of the
Muscular System
1. Gluteus Maximus –
largest muscle in the
body
2. Bicep/Tricep – move
arm
The Function of the Muscular System
Muscles work together with bones to provide
the body with movement.
B. Three Types of muscle
1. Skeletal muscle- Voluntary - enables
bones to move
2. Smooth muscle- Involuntary - moves
food through the digestive tract and
controls blood flow.
3. Cardiac muscle- Involuntary - Found
only in the heart
How the Muscles Work
• Skeletal muscles pull on the bones to produce
movement.
– Tendons connect bone to muscle
Figure 36-5 Knee Joint
Section 36-1
Muscle
Tendon
Femur
Patella
Bursa
Ligament
Synovial fluid
Cartilage
Fat
Fibula
Tibia
How the Muscles Work
Muscles work in pairs
1. When a muscle
bends a part of your
body it is called a
flexor.
2. When a muscle
straightens a part of
your body it is called
a extensor.
Figure 36-11 Opposing Muscle Pairs
Section 36-2
Movement
Movement
Biceps (relaxed)
Triceps (contracted)
Biceps (contracted)
Triceps (relaxed)
Conditions of the Muscular System
Muscular Dystrophy
Inherited Disorder that causes
damage to muscle fibers
Cerebral Palsy
Disorder in which damage to the brain
results in loss of muscle control
Marfan Syndrome
Disease of the connective
Tissue
– Curvature of the spine
(Scoliosis)
– Bulging aorta
– Sunken chest
– Flexible joints
– Longer bones in hands and
feet
– Flat and crowded teeth
Marfan is a Dominant Trait
Mm
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