INTEGUMENTARY SYSTEM - Orange Coast College
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Transcript INTEGUMENTARY SYSTEM - Orange Coast College
SKELETAL SYSTEM
SKELETAL SYSTEM
FUNCTIONS
Support (Primary function)
Movement (Passive)
Protection of Vital Organs
Mineral Storage
Blood Cell Formation (Hematopoiesis or
Hemopoiesis)
OSSEOUS C.T.
Compact (dense) Bone
- Hard & heavy
- Forms surface & diaphysis
- Osteons = building blocks
Cancellous (spongy) Bone
- Lightweight
- Fills epiphyses, Contains red marrow
- Trabeculae = building blocks
Matrix
- Mineral Salts (hardness)
- Collagen (strong & flexible)
Two Types of Bone
Compact Bone
Spongy Bone
Bone Cells
Osteoblasts – Secrete to form bone
Osteocytes
* Mature bone cells
* “Trapped” osteoblasts
Osteoclasts – destroy bone
* Enzymes digest protein
* Acids dissolve minerals
* Forms Marrow Cavity; Involved in
Remodeling
Osteoblasts & Osteocytes
Osteoclast
SKELETAL DIVISIONS
Axial
Appendicular
Classification: Shape & Location
Long
Short
Flat
Irregular
Sesamoid (develop in
tendons; patella)
Sutural (between
cranial bones)
Torus Bones
LONG BONE ANATOMY
Diaphysis = shaft made of
compact bone
Epiphyses = ends filled
with spongy bone
containing red marrow
Articular cartilage covers
epiphyses
Epiphyseal line indicates
earlier location of
epiphyseal (growth) plate
LONG BONE ANATOMY
Periosteum is C.T.
covering bone
Nutrient Foramina –
holes allowing for
penetration of arteries
Medullary cavity
contains yellow marrow
Endosteum is C.T.
lining medullary cavity
BONE DEVELOPMENT
Ossification = replacement of other
connective tissue with bone
Begins during the 2nd month of gestation
Size increases until late teens (females) to
mid-twenties (males)
Ossification processes include:
- Intramembranous bone formation
- Endochondral bone formation
INTRAMEMBRANOUS
OSSIFICATION
Occurs in flat bones of skull,
clavicles, mandible
Begins with fibrous C.T.
membrane
Membrane calcifies & ossifies
into bone
Fontanels
- “Soft spot”, not yet ossified
- Allows for birth & brain
growth
Process of Intramembranous
Ossification
Embryonic C.T.
cells cluster &
differentiate
Osteoblasts form &
produce matrix =
ossification center
Newly formed
matrix calcifies
Osteocytes form
Process of Intramembranous
Ossification
Trabeculae form;
periosteum forms from
surrounding condensed
embryonic C.T.
Surface trabeculae fill
with matrix, forming
compact bone
ENDOCHONDRAL
OSSIFICATION
Occurs in remainder of skeleton
Begins with hyaline cartilage model
Cartilage is replaced by bony tissue
Steps include:
-
Bone collar forms
Cartilage in shaft calcifies
Primary Ossification center forms in shaft
Secondary Ossification centers in epiphyses
Formation of Bone Collar &
Primary Ossification Center
Formation of Secondary
Ossification Centers
Epiphyseal Plates & Articular
Cartilage
APPOSITIONAL GROWTH
Bone Widens
Osteoclasts enlarge medullary cavity
Osteoblasts add bone to surface of diaphysis
BONE REMODELING
Replacement of old bone with new bone
Involves resorption (osteoclasts) &
deposition (osteoblasts)
Alters bone shape in response to stress
Benefits:
- Allows for growth
- Removes injured bone
- New bone is more resistant to fracture
FRACTURES AND THEIR
REPAIR
Definition: Any break in a bone
Repair may take months
Requires:
-
Adequate minerals
Vitamins
Hormones
Weight-bearing exercise
STEPS IN FRACTURE REPAIR
Broken blood vessels form a hematoma
(blood clot)
C.T. and Capillaries invade site; C.T. cells
form fibrocartilage callus
Bony callus of spongy bone replaces
fibrocartilage callus
Bony callus is remodeled
Types of Fractures
Open (Compound) –
Broken bone ends
protrude through the
skin
Closed (Simple) –
Bone does not
penetrate the skin
Types of Fractures
Comminuted – splintered,
crushed; small pieces between
broken ends. Elderly. Most
difficult to treat.
Greenstick – Partial fracture;
one side breaks, other side
bends. Children.
Types of Fractures
Impacted – One end of
fractured bone
forcefully driven into
other end
Spiral – fracture spirals around
long bone axis from twisting
force
Types of Fractures
Pott’s – distal end of
fibula, tibia or both
Colles’ – distal end of
radius
Types of Fractures
Stress Fracture
- Fracture without visible break
- Microscopic fissures
- No apparent damage to surrounding
tissues
- Result from repeated, strenuous
activities
- Can result from reduced calcium
deposition in disease
- 25% involve tibia
BONES AS LEVERS
Lever: A rigid rod that moves about a fixed point
Fulcrum: The fixed point around which a lever
moves (joints)
Forces: Act to move levers at two points
- Resistance: Force to be overcome
- Effort or Work: Force required to overcome
resistance; supplied by skeletal muscles
CLASSES OF LEVERS
First Class: The fulcrum is between the
effort/force and the resistance
- Seesaw
- Tilting head backward
FIRST CLASS LEVER
R
F
E
CLASSES OF LEVERS
CONTINUED
Second Class: Resistance is between the
fulcrum and the effort/force
- Wheelbarrow
- Rising up on
one’s toes
SECOND CLASS LEVER
E
R
F
CLASSES OF LEVERS
CONTINUED
Third Class: The effort/force is between
the fulcrum and the resistance
- Most common type in the human body
- Flexing the elbow
THIRD CLASS LEVER
E
R
F
CLASSIFICATION OF JOINTS
Structural
- Based on what tissues or structures are found
between the bones
- Fibrous, Cartilagenous, Synovial
Functional
- Based on amount of movement (& amount of
movement is determined by structures found
between bones)
- Freely movable, Slightly movable, Immovable
ARTICULATIONS:
CLASSIFICATION BY
STRUCTURE
C L ASSIF IC AT IO N
ST R U C T U R E
F ib r o u s jo in t
S u t u r es o f sk u ll
C ar t ilag en o u s jo in t
P u b ic sym p h ysis
S yn o vial jo in t
K n ee
ARTICULATIONS:
CLASSIFICATION BY
FUNCTION
C L ASSIF IC AT IO N
F U N C T IO N
S yn ar t h r o sis
I m m o vab le
jo in t s
A m p h iar t h r o sis
S lig h t ly m o vab le
jo in t s
D iar t h r o sis
F r eely m o vab le
jo in t s
ARTICULATIONS: EXAMPLES
Sutures
Functional: Synarthrosis
Structural: Fibrous
Pubic symphysis
Functional: Amphiarthrosis
Structural: Cartilagenous
Knee
Functional: Diarthrosis
Structural: Synovial
STRUCTURE OF A
SYNOVIAL JOINT
Articular cartilage – covers bone ends
Synovial membrane – lines joint capsule
Synovial fluid – lubricates & nourishes
cartilage
Synovial cavity – space between the bones
Joint capsule – fibrous C.T.
Ligaments – reinforce joint
Bursae – synovial sacs at other sites of
friction
TYPES OF SYNOVIAL
JOINTS
Classified based on shape of articular
surfaces
Gliding (plane)
Hinge
Pivot
Ellipsoidal (condyloid)
Saddle
Ball-and-socket