Download The Skeletal System

The Skeletal System
Objectives
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Describe the structure & functions of
the skeletal system.
Identify 4 types of bones.
Learn the names of major bones.
Learn the 4 types of joints
Skeletal System
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Bones
Ligaments
Tendons
Cartilages
I. Functions of the
Skeletal System
1. Support
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bones of the legs, pelvic girdle, and
vertebral column support the weight of the
body.
The mandible (jawbone) supports the teeth.
Other bones support various organs and
tissues.
2. Protection
The bones of skull
protect the brain.
The ribs and sternum
protect
The
heart
and
lungs.
Vertebrae protect spinal
cord
3. Movement
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Skeletal muscles attach to bones to
move the body.
4. Minerals
The bones are the storage center for:
 Calcium 99%
 Phosphorus 85% (phosphorus
helps calcium keep our bones
strong)
5. Blood Cell Formation
Bones manufacture the body’s blood
cells
 Red bone marrow produces millions of
blood cells each day
 Adipose (fat) tissue is found in yellow
marrow of certain bones.
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II. Structure of the Skeleton
206 Bones
in the Human Body
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22 bones in skull
6 in middle ears
1 hyoid bone….this is the only
bone NOT connected to any other…do
you know where its located?
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26 in vertebral column
25 in thoracic cage
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4 in pectoral girdle
60 in upper limbs
60 in lower limbs
2 in pelvic girdle
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206 TOTAL
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Skeletal System divided
into 2 main parts
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Axial Skeleton – 80 bones
– skull, vertebral column,
and rib cage.
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Appendicular skeleton - 126 bones
– Bones of upper & lower limbs and the
girdles (shoulder bones and hip bones)
4 Types of Bones
1. Long Bones
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Much longer than
they are wide.
All bones of the
limbs except for
the patella
(kneecap),
and the bones of
the wrist and
ankle.
Consists of a shaft
plus 2 expanded
ends.
2. Short Bones
Cubed shaped
bones of the
wrist and
the ankle.
Carpal Bones
3. Flat Bones
 Thin,
flattened,
and usually a
bit curved.
 Scapulae,
sternum,
(shoulder
blades), ribs
and most
bones of the
skull.
Sternum
4. Irregular Bones
 Have
weird shapes that fit none of the 3
previous classes.
 Vertebrae, hip bones, 2 skull bones
(sphenoid and the ethmoid bones).
Sphenoid Bone
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All bones consist of a dense, solid
outer layer known as compact bone
and an inner layer of spongy bone – a
honeycomb of flat, needle-like
projections called trabeculae.
A. Long Bone Structure
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Shaft plus 2 expanded ends.
Shaft is known as the diaphysis.
– Consists of a thick collar of compact bone
surrounding a central marrow cavity
– In adults, the marrow cavity contains fat
or yellow bone marrow.
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Expanded ends are epiphyses
– Thin layer of compact bone covering an
interior of spongy bone.
– Joint surface of each epiphysis is covered
w/ articular cartilage. It cushions the
bone ends and reduces friction during
movement.
Cartilage
 The
skeletal
system is made up
of not only bones
but Cartilage, a
strong, flexible
connective tissue.
Cartilage
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Cartilage serves many functions :
 Lines the surfaces of joints and
enables them to move smoothly
 Cushions joining vertebrae
 Supports the nose and ears
 Baby skeleton is mostly
cartilage
Cartilage
 Cartilage
cells are replaced
with age by bone cells and
minerals in a process call
Ossification
 The process by which bone
is formed, renewed and
repaired
4 Types of Joints in the
Body
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1. Ball and Socket
Joint
– Hip and Shoulder
2. Hinge Joint
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Elbow, Knee and
Fingers
3. Gliding Joint
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Small bones of Wrist
4. Pivot Joint
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Skull and Vertebrae
Ligaments
A band of
elastic Connective
Tissue
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Connects a
bone to a bone
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i.e. ACL
Tendon
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Connects
a muscle
to a bone.
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i.e. Quadriceps
Tendon
Facts on Tendons,
Muscles & Movement
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Tendon – fibrous
cord attaches
muscle to bone ,
when muscle
contact they move
the bone.
Major Bones of the Skeleton
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Skull
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Vertebrae
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Ribs
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Humerus
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Radius
Major Bones of the Skeleton
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Ulna
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Pelvis
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Femur
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Tibia
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Fibula
The
axial
skeleton
The skull
Cranium - 8 sutured bones
Facial bones: 13 sutured bones, 1 mandible
Cranium
 encases brain
 attachments for muscles
 sinuses
Skull top view
Vertebral column
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7 cervial vertebrae
12 thoracic vertebrae
5 lumbar vertebrae
1 sacrum (5 fused
1 coccyx (4 fused)
26 total
Vertebrae vary in size and shape
Spinal Column
Sacrum & Coccyx
Thoracic cage
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ribs
thoracic vertebrae
sternum
costal cartilages
True ribs are directly attached to the
sternum
(first seven pairs)
Three false ribs are joined to the 7th rib
Two pairs of floating ribs
The
Appendicular
Skeleton
Clavicles and scapulae
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Help brace shoulders
Attachment sites for muscles
Scapula
Coracoid Process
Spine
Acromion
Glenoid Cavity
Scapula and humerus
Bones of upper limb
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Humerus (upper arm)
Radius; ulna
Carpals, metacarpals, phalanges
Raduis & Ulna –Wrist &
elbow joints
Radius and Ulna
The Hand
Wrist / Carpals
The pelvic Girdle / Pelvis
ILIUM
SACRUM
ACETABULUM
ISCHIUM
PUBIC SYMPHISIS
PUBIS
Bones of lower limb
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Femur
Patella
Tibia, fibula
Tarsals, metatarslas, phalanges
Femur / thigh bone
Fibula and Tibia
Foot and ankle