Download 6-1 Checkpoint - Jordan High School

Chapter 6
The Skeletal System
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6-1: Skeletal System Functions

Skeletal system supports body weight &
helps body to move

Includes bones, cartilages, joints,
ligaments, & connective tissues
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
Functions of skeletal system:
– Support—provides framework of body
– Storage—stores calcium
– Blood cell production—produces red blood
cells
– Protection—surrounds soft tissues &
organs
– Movement—works with skeletal muscle
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6-1 Checkpoint
1.
Name the five primary functions of the
skeletal system.
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6-2: Bone Classification

Bone consists of cells, fibers, & calcium
phosphate
Macroscopic Features of Bone

Types of bone:
– Long
– Short
– Flat
– Irregular
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
Long bone features:
– Diaphysis (shaft) surrounds a marrow
cavity containing bone marrow
– Epiphysis at each end of the bone

Bone tissue
– Compact bone (in diaphysis)
– Spongy bone (in epiphysis)

Periosteum covers bone; endosteum
is within bone
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Microscopic Features of Bone

Osteocytes (bone cells) are found in
lacunae
– Lacunae arrange in layers (lamellae)
– Channels (canaliculi) connect lacunae

Osteon composes compact bone
– Lamellae arrange around a central canal
of blood vessels
– Perforating canals connect blood vessels
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Cells in Bone

Osteocytes (bone cells) maintain bone
structure

Osteoclasts dissolve bone
– Release calcium into the bloodstream

Osteoblasts build bone through
ossification
– Remove calcium from bloodstream
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6-2 Checkpoint
1.
Identify the four shapes of bones.
2.
Mature bone cells are known as
bone-building cells are known as
and
are bone-dissolving cells.
3.
If the activity of osteoclasts exceeds
that of osteoblasts in a bone, how will
the mass of the bone be affected?
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,
,
6-3: Bone Formation

During development, cartilage & tissues
are replaced by bone (ossification)
Intramembranous Ossification

Sheets of membranes ossify and form
the flat bones
– Skull, clavicles, jaw
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Endochondral Ossification

Forms most of the skeleton’s bones

Cartilage replaced by bone
– A cartilage model develops
– Cartilage cells get replaced by osteoblasts
at primary ossification center
– Epiphyseal plates (growth plates) form
at ends of bone
– Secondary ossification center continues
lengthening bone
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Requirements for Bone Growth

Normal bone growth depends on:
– Calcium intake
– Vitamin D—helps with calcium absorption
– Vitamin A & C—needed for bone growth &
maintenance
– Hormones
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6-3 Checkpoint
1.
How could x-rays of the femur be used
to determine whether a person has
reached full height?
2.
Why are pregnant women given
calcium supplements and encouraged
to drink milk even though their
skeletons are fully formed?
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6-4: Bone Homeostasis

Bones are recycled & replaced each
year through remodeling by
osteoclasts & osteoblasts
Remodeling & Support

Stressed bones become thicker &
stronger
– Exercise helps strengthen bones
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Repair of Fractures

Fracture—crack or break in bone

Steps in healing bone:
– Bleeding occurs & a clot is formed
– An external callus forms over an
internal callus
– Osteoblasts reform damaged bone
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Classification of Fractures

Nondisplaced (bone ends keep
position) vs. displaced (bone ends out
of alignment)
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
Complete break (broken through) vs.
incomplete break (not broken
through)
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
Linear (break parallel to bone axis) vs.
transverse (break perpendicular to
bone axis)
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
Open fracture (bone ends penetrate
skin) vs. closed fracture (bone ends
don’t penetrate skin)
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6-4 Checkpoint
1.
Describe bone remodeling.
2.
Why would you expect the arm bones
of a weight lifter to be thicker &
heavier than those of a jogger?
3.
What is the difference between an
closed fracture & an open fracture?
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6-5: Osteoporosis

Bones become thinner & weaker with
age

Osteoporosis—loss of bone density &
mass; bones become more porous
– More common in women
– Prevention: calcium, vitamin D, exercise
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6-5 Checkpoint
1.
Define osteoporosis.
2.
Why is osteoporosis more common in
older women than in older men?
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6-6: Skeletal Divisions

Bones have external features for muscle
attachment, passage of nerves & blood
vessels
Skeletal Divisions

Axial skeleton includes the skull, rib
cage, & vertebral column

Appendicular skeleton includes the
arms, legs, pectoral & pelvic girdles
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6-6 Checkpoint
1.
List the parts of the axial skeleton and
the appendicular skeleton.
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6-7: Axial Skeleton

Supports & protects brain, spinal cord,
organs in thoracic cavity
The Skull

Composed of the cranium & facial
bones
– Also includes auditory ossicles (ear bones)
& hyoid bone (tongue attachment)
Bones of the Cranium

Frontal bone
– Forms forehead; contains sinuses to
lighten skull

Parietal bones
– Forms top of skull

Occipital bone
– Forms back of skull; contains foramen
magnum for spinal cord
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
Temporal bone
– Forms sides of skull; contains external
acoustic meatus, mastoid & styloid
processes

Sphenoid & ethmoid bones
– Form floor of skull

Sutures connect cranial bones
– Coronal, sagittal, lambdoid,
squamous
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Bones of the Face

Maxillae form the upper jaw

Palatine bones form roof of mouth

Vomer forms nasal septum

Zygomatic bones form cheeks

Nasal bones form bridge of nose

Mandible is the lower jaw
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Vertebral Column

Vertebral column protects the spinal
cord, supports weight of skull
– Consists of vertebrae, sacrum & coccyx

Divisions of vertebral column:
– Cervical (7 vertebrae)
– Thoracic (12 vertebrae)
– Lumbar (5 vertebrae)
– Sacral & coccygeal (fused vertebrae)
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
Parts of a vertebra:
– Vertebral body—bears weight of spine
– Intervertebral disc—pad between
vertebrae
– Vertebral arch—bone around vertebral
foramen (hole for spinal cord)
– Pedicles—attach vertebral arch to body
– Spinous process & transverse processes—
attach muscles
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
Cervical vertebrae
– Have transverse foramina for blood
vessels to brain
– Include atlas (C1) & axis (C2)

Thoracic vertebrae
– Heart-shaped body; spinous process points
down

Lumbar vertebrae
– Largest vertebrae; support body weight
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
Sacrum & coccyx
– Fused vertebrae; provide muscle
attachment
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The Thoracic Cage

Divisions of ribs:
– Ribs 1 – 7: true ribs (attach to sternum)
– Ribs 8 – 10: false ribs (attach to
cartilage)
– Ribs 11 & 12: floating ribs (don’t attach)

Ribs attach muscles & help in breathing

Sternum has three parts:
– Manubrium, body, & xiphoid process
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6-7 Checkpoint
1.
Which bone of the cranium joins
directly with the vertebral column?
2.
What are the sutures of the skull, and
where are they found?
3.
Why are the bodies of lumbar
vertebrae so large?
4.
What are the differences between true
ribs & false ribs?
6-8: Appendicular Skeleton

Includes bones of upper & lower limbs,
pectoral & pelvic girdles
The Pectoral Girdle

Joins upper limb to chest

Clavicle
– Brace shoulders & connect to sternum

Scapula
– Flat triangular bone; provides muscle
attachment points

Scapula joins humerus at glenoid
cavity to form shoulder joint

Processes:
– Acromion joins with clavicle
– Coracoid process anchors biceps
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The Upper Limb

Humerus contains many structures on
distal end:
– Medial & lateral epicondyles
– Trochlea & capitulum—connect to radius
& ulna
– Coronoid & olecranon fossa—
depressions for ulnar processes
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
Forearm contains radius & ulna

Ulna is on medial side of forearm
– Contains olecranon & coronoid
processes for connection with humerus

Radius is on lateral side of forearm
– Rotates over ulna
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
Wrist, hand & fingers
– Carpals compose wrist bones
– Metacarpals compose palm of hand
– Phalanges compose fingers
»Each finger has 3 phalanges; thumb has
2 phalanges
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The Pelvic Girdle

Joins with lower limbs for movement
– Consists of 2 coxal bones

Each coxal bone is 3 fused bones
– Ilium forms upper crest of pelvis
– Ischium supports weight while sitting
– Pubis connects coxal bones at pubic
symphysis
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
Gender differences in pelvis:
– Female pelvis is smoother, broader & lower
than male pelvis
– Female pelvis has larger pelvic outlet
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The Lower Limb

Femur is the largest & strongest bone
in the body
– Joins the coxal bone at the acetabulum
– Lateral & medial condyles join with tibia
to form knee joint

Patella forms the kneecap
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
Lower leg contains tibia & fibula

Tibia forms the shin bone
– Medial malleolus forms inner ankle

Fibula found on lateral side of leg
– Provides stability
– Lateral malleolus forms outer ankle
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
Ankle, foot, & toes
– Tarsals compose ankle; calcaneus is heel
bone
– Metatarsals compose arch of foot
– Phalanges compose toes
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6-8 Checkpoint
1.
The rounded projections on each side
of the elbow are parts of which bone?
2.
Which of the 2 arm bones is lateral in
anatomical position?
3.
Which 3 bones make up a coxal bone?
4.
When someone breaks their heel bone,
what bone is most likely broken?
6-9: Joints

Joints exist where 2 bones meet

Structural classification of joints:
– Fibrous (no movement)
– Cartilaginous (limited movement)
– Synovial (freely movable)

Functional classification of joints
– Synarthrosis (immovable)
– Amphiarthrosis (slightly movable)
– Diarthroisis (freely movable)
Immovable Joints (Synarthroses)

Can be fibrous or cartilaginous

Found in sutures of skull, teeth
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Slightly Movable Joints
(Amphiarthroses)

Can be fibrous or cartilaginous

Found in joint between tibia & fibula,
pubic symphysis, intervertebral discs
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Freely Movable Joints
(Diarthroses)

Also called synovial joints

Found at ends of bones
– Covered with articular cartilages

Joint is surrounded by joint capsule
with synovial fluid
– Menisci & bursae absorb shock
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Arthritis

Pain, stiffness, & swelling of joint

Osteoarthritis
– Most common type; found in older
population

Rheumatoid arthritis
– Body’s immune system attacks its own
tissues
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CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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6-9 Checkpoint
1.
Name & describe the 3 types of joints
classified by the amount of movement
possible.
2.
Bones of the skull are joined by fibrous
connective tissue. What type of joint
is this?
3.
What is arthritis?
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6-10: Joint Movements
Types of Movements—Gliding

Two surfaces slide past each other
– Between carpals/tarsals
Angular Movements

Flexion/extension
– Decreases/increases angle between bones

Hyperextension
– Extension past anatomical position

Abduction/adduction
– Moving away/towards midline of body

Circumduction
– Moving body part in a large circle
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Rotational Movements

Rotation
– Turning around an axis (looking L & R)

Pronation/supination
– Turning palm down/palm up
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Special Movements

Inversion/eversion
– Twisting sole of foot outward/inward

Dorsiflexion/plantar flexion
– Lifting top of foot up/pushing foot down

Protraction/retraction
– Push body part forward/pull back body part

Elevation/depression
– Lift body part up/lower body part
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Types of Synovial Joints

Gliding joints—surfaces slide
– Ex: carpals, tarsals

Hinge joints—move in one direction
– Ex: elbow, knee

Pivot joints—allow rotation
– Ex: atlas/axis, radius/ulna
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
Condylar joint—oval surface rests in a
depression
– Ex: radius/carpals, phalanges &
metacarpals/metatarsals

Saddle joints—concave & convex
surfaces fit together
– Ex: thumb

Ball-and-socket joints—head fits in a
cup-shaped depression
– Ex: shoulder, hip
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6-10 Checkpoint
1.
Give the proper term for each of the
following types of motion: (a) moving
the humerus away from the body; (b)
turning the palms up; (c) bending the
elbow.
2.
What are the 6 types of synovial
joints?
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