Please enable JavaScript.
Coggle requires JavaScript to display documents.
Chapter 6 (6-2 classifying bones to shape (Parts of a long bone…
Chapter 6
6-2 classifying bones to shape
Bones are classified according to their shape
flat bones are thin and usually curved
breast bone= sternum
shoulder bones= scapulae
most skull bones
irregular bones are not long, short, or flat
auditory ossicles
verebrae
Short bones are cube-like
ankle bones= tarsals
wrist bones= carpals
sesamoid bones develop within a tendon
the patella is a human sesamoid bone
Long bones consists of a shaft with two ends
thigh bone= femur
upper arm bone= humerus
Parts of a long bone
Epiphyseal line= remnant of epiphyseal disk/plate
cartilage at the junction of the diaphysis and epiphyses (growth plate)
Periosteum= outer, fibrous, protective covering of diaphysis
richly supplied with blood and lymph vessels, nerves (nutrition)
nutrient foramen= perforating canal allowing blood vessels to enter and leave bone
osteogenic layer contains osteoblasts and osteoclasts
serves as insertion for tendons and ligaments
Epiphyses= expanded ends
consists mainly of spongy bone
surrounded by a thin layer of compact bone
Endosteum- inner lining of medullary cavity
contains layer of osteoblasts and osteoclasts
Diaphysis= Shaft
consists of a central medullary cavity (filled with yellow marrow)
surrounded by a thick collar of compact bone
Articular Cartilage- pad of hyaline cartilage on the epiphyses where long bones articulate or join
"Shock absorber"
Parts of a flat bone
covered by periosteum-covered compact bone
surrounding endosteum-covered spongy bone
in a flat bone, the arrangement looks like a sandwich
spongy bone (meat), sandwiched between two layers of compact bone (bread)
hematopoietic tissue (red marrow) is located in the spongy bone within the epiphyses of long bones and flat bones
Chemical composition of bone (both organic and inorganic)
Organic Components
osteoprogenitor cells
derived from mesenchyme
can undergo mitosis and become osteoblasts
osteocytes
mature bone cells derived from osteoblasts
principle bone cell
cannot undergo mitosis
maintain daily cellular activities
osteoclasts
functions in bone resorption
important in development, growth, maintenance and repair of bone
osteoblasts
form bone matrix by secreting collagen
cannot undergo mitosis
osteoid
also contains glycolipids and glycoproteins
primarily collagen which gives bone its high tensile strength
inorganic component
hydroxyapatite which is primarily
calcium phosphate which gives the bone its hardness or rigidity
Microscopic structure of compact bone
compact bone is solid, dense, and smooth
structural unit= haversian system or osteon
elongated cylinders cemented together to form the long axis of a bone
components of haversian system:
osteocytes that lie in "lacunae" that have laid down a matrix of collagen and calcium salts in concentic lamellae around a central haversian canal containing blood vessels and nerves
communicating canals within compact bone
canaliculi connect the lacunae of osteocytes
voliemann's canals connect the blood and nerve supply of adjacent haversian systems together
run at right angles to and connects adjacent haversian canals
microscopic structure of spongy (cancellous) bone
with a lot of open space between them
nourished by diffusion from nearby haversian canals
consists of poorly organized trabeculae (small needle- like pieces of bone)
6-4 the remodeling & homeostatic of the skeletal system
Once a bone has been formed, it is completely being remodeled throughout life. This process involves the action of osteoblasts and osteocalsts, two hormones (caclitonin and parathyroid hormone and in turn affects blood calcium homeostasis
Rate of Remodeling Varies
Distal Femur is replaced every four months
Diaphysis may not be fully replaced during one's lifetime
Osteoclasts are large multinucleated cells responsible for bone resorption
secretes lysosomal enzymes thay digest the organic matrix
secrete acids that decompose calcium salts into Ca and PO ions, which can then enter blood
Control of bone remodeling
involves 2 hormones (negative feedback)
Parathyroid hormone (PTH)- which is secreted by the parathyroid when blood calcium levels are low
causes kidney tubules to reabsorb Ca back into in the blood
causes intestinal mucosa to increase dietary absorption of Ca and therefore
stimulates osteoclast activity (resorption of bone occurs) which releases Ca into the blood
causes an increase in blood calcium levels (back to normal)
calcitonin- which is secreted by the thyroid gland when blood calcium levels are high
causes the kidney tubules to secrete excess Ca into the urine and therefore
results in a decreases in blood calcium levels (back to normal)
inhibits bone resorption, increases osteoblast activity (causes a deposition of bone matrix)
control of bone remodeling & calcium homeostasis
Factors affecting bone development, growth and repair
magnesium (needed for normal osteoblast activity)
Boron (inhibits calcium loss)
Phosphorus (component of hydroxyapatite
calcium (component of hyrdroxyaptite matrix)
Manganese (needed for new matrix)
Vitamins needed for bone growth, remodeling and repair
Vitamin C- helps maintain bone matrix (collagen synthesis)
deficiency causes scurvy
Vitamin A- is required for bone resorption, controls, the activity, distribution and coordination of osteoblasts and osteoclasts during development
Vitamin D- greatly increases intestinal absorption of dietary calcium and retards its urine loss
deficiency causes rickets in children and osteomalacia in adults
Vitamin B12- may play a role in osteoblast activity
6-10 Types of Synovial Joints
Gliding Joints- cartilaginous Joints
EX: intervertebral discs
hinge joints- permit flexion and extension only
EX: elbow and knee
Saddle Joints- Thumb
Pivot Joints- permit rotation EX: first intervertebral joint
Ball & Socket Joints- most freely moveable joints; all angular movement
the head of one bone fits into the socket of another
EX: hip and shoulder
Condyloid Joints (ellipsoidal)- permit all angular motion, except rotation EX: wrists and knuckles
Types of joint movements
Definitions
origin- part of muscle attached to the immoveable bone
insertion- part of a muscle attached to the moveable bone
3 general types of movements
gliding movements- when flat bone surfaces glide or slide over one another, occur at cartilaginous joints. EX: intervertebral discs and sternoclavicular joints
Angular Movements- changes in angles between bones; occur only at synovial joints
Flexion- decreasing the angle between 2 bones EX: head toward chest
Dorsiflexion- bringing foot closer to shin
Plantarflexion- pointing one's toe
Extension- increasing the angle between 2 bones EX: straightening a flexed neck
Hyperextension- increasing the angle greater than 180
Abduction- moving a limb away from the midline EX: raising arm or thigh laterally
Adduction- moving a limb toward the midline
Circumduction- moving a limb in a circular manner
Rotation- turning movement of a bone along its long axis EX: atlas over axis & shoulder and hip joint
Special Movements- those at specific joints
Inversion/Eversion- movement of foot
sole inward- inversion
sole out- eversion
Elevation/Depression
shoulder shrug- elevation
mandible in opening mouth- depression
Protraction/Retraction
Thrust forward- protraction
Pull back- retraction
Supination/Pronation- movements between the radius and ulna at the proximal radioulnar joint
Thumb up- supination
Thumb down- pronation
6-1 Primary function of the skeletal system
Body Movement
skeletal muscles attached to bones by tendons
Hematopoiesis- blood cell formation
all blood cells are formed in the red marrow of certain bones
Protection
the skull protects the brain
the rib cage protects the heart and lungs
Inorganic salt storage
bone stores many minerals; calcium, phosphorus, and others
also a means of calcium homeostasis
Support
the bones in legs and plevis support the trunk
the atlas supports the skull
energy storage
yellow marrow in the shaft of long bones
serve as an important chemical energy reserve
6-6 the components and functions of the axial and appendicular skeletons
Axial Skeleton- consists of 206 bones and joints that allow for many functions
axial- includes bones of the skull, hyoid bone, vertebral column and thoracic cage
appendicular- includes the limbs of upper and lower extremities and the bones that attach those limbs to the trunk
Cranium- brain case or helmet, composed of eight bones which include the frontal, occipital, sphenoid, and ethmoid bones along with parietal and temporal bones
parietal bones- behind frontal bone; bulging sides of skull
posteriorly with occipital bone at lamboidal suture
laterally with temporally bones at squamous suture
anteriorly with frontal bones at coronal suture
between bones at sagittal suture
occipital bone- base of skull
foramen magnum (large hole)- opening in occipital bone where nerve fibers pass from brain into spinal cord
occipital condyles- rounded processes on either side of foramen magnum which articulate with the first vertebra (atlas)
articulates with paired parietal bones along the lambdoidal suture
frontal bone- forehead
contains 2 frontal sinuses
forms superior portion of orbit
articulates with parietal bones along coronal suture
temporal bone- lie inferior to parietal bones at squamous suture
external auditory meatus- opening in tympanic region which opens to the inner portions of the ear
styloid process- needle like extension (attachment for some neck muscles)
zygomatic process- bar like extension that meets the zygomatic bone
sphenoid bone- butterfly shaped bone that spans the length of the cranial floor
lateral portions are wedged between many other skull bones= keystone
contains two sphenoid sinuses
sella turcica= portion of sphenoid bone which rises up and form a saddle shaped mass that houses the pituitary gland
ethmoid bone- complex shaped bone composed of two masses on either side of the nasal cavity
cribriform or horizontal plate connects two masses of eithmoid bone horizontally
perpendicular plate projects downward from cribriform plate to form superior portion of nasal septum
nasal concha- delicate scroll-shaped plates that project into nasal cavity
crista galli- process that extends from horizontal plate that serves as the attachment fort meninges (membranes that surround the brain
contains two ethmoid sinuses
Facial Skeleton- shapes the face and provides attachment for various muscles that move the jaw and control facial expressions
lacrimal bones- median walls of orbit
composed of seven bone
contains lacrimal foramen for tear drainage
nasal bones- bridge of nose
zygomatic bones- cheek bones
temporal process projects posteriorly and articulates with the zygomatic process of temporal bone
vomer- inferior portion of nasal septum
the perpendicular plate of the ethmoid bone forms the superior portion of nasal septum
palatine bones- complete posterior portion of hard palate
cleft palate
inferior nasal conchae
maxillary bones (maxillae)- upper jaw
contains two maxillary sinuses
mandible- lower jaw
largest, strongest bone in the face
mandibular condyle articulates with the madibular fossa of the temporal bone at temporomandibular joint (TMJ)
only moveable bone in the skull
Hyoid bone: location- in neck between lower jaw and larynx held in place by muscles and ligaments Function- supports tongue
infantile skull- differs from the adult skull in the following ways:
large forehead and small face
larger orbits
fontanels
soft spots
allow "molding" of skull in birth canal
vertebral column
4 curvatures exist in the sagittal plane
secondary curvatures
are convex anteriorly
cervical curvature is in cervical region
develops as baby starts to hold up head
develop during infancy
lumbar curvature is in lumbar region
develops as baby begins to stand
intervertebral disk- protective pad of fibrocartilage between individual vertebra
a slightly movable joint
primary curvatures
are concave anteriorly
thoracic curvature is in thoracic region
exist at birth
pelvic curvature is in the sacral and coccygeal regions
typical vertebra
vertebral foramen- opening between body and vertebral arch through which the spinal cord passes
spinous process- midline posterior projection
vertebral arch- posterior region
pedicle- short bony posterior projection
lamina-flattened plates that articulate posteriorly into spinous process
transverse process- laterally from pedicle
body- discoid shaped anterior region
thoracic cage- includes the ribs, sternum, thoracic, vertebrae and costal cartilages
Ribs- 12 pairs
articulate anteriorly with sternum through costal (hyaline cartliage)
three types:
true ribs= upper 7 pairs that articulate directly with sternum
false ribs= remaining 5 pairs of ribs
floating ribs= 11 & 12th pair; these ribs do not articulate anteriorly
articulate posteriorly with thoracic vertebrae
Typical rib structure:
neck
tubercle
articular
non-articular
head
superior facet
inferior facet
costal angle
costal angle
body
Sternum; three parts-
manubrium= upper portion
resembles handle
articulates with clavicle
body= middle vertical portion
site where most ribs articulate anteriorly
xiphoid process= lower extension from body
33 infantile or 26 adult irregular bones are divided into 5 regions
thoracic region= 12 vertebrae in thoracic cavity
lumber region= 5 large vertebrae in abdominal cavity
cervical region= 7 vertebrae bones in neck; atlas & axis
sacrum= 5 fused vertebrae that articulate with coxal bones of pelvis
coccyx= 3-5 vertebrae which makeup the tailbone
6-11 Relationship between joint structure and mobility of the axial and appendicular articulations
Elbow Joint (2 joints)
Hinge is between trochlea of humerus and trochelar notch of ulna
gliding joint is between capitulum of humerus and head of radius
very stable joint with many reinforcing ligaments
only allows flexion and extension
Hip Joint (Coxal Joint)
Contains many large reinforcing ligaments
Allows same movements as shoulder, but with less range due to bony limitations
Ball & socket between head and femur and acetabulum of coxa
Shoulder Joint (2 Joints)
Syndesmosis is called the acromioclavicular joint, acromial end of clavicle and the acromion process of the scapula
ball & socket is surrounded by many reinforcing ligaments and tendons collectively called the rotator cuff
Many bursa also lubricate the shoulder
ball & socket is the glenohumeral joint- joins glenoid cavity and head of humerus
Movement can occur in any angular plane
Knee (3 joints)
largest, most complex joint
functions as a hinge even though 3 joints work together
medial condyles of femur and tibia make one condyloid joint
lateral condyles of femur and tibia make another condyloid joint
patellar surface of femur and patella make a gliding joint
Flexion and extension with some slight rotation
contains many reinforcing structures
Ligaments
Intracapsular Ligaments- found inside joint capsule
posterior cruciate ligament PCL
anterior cruciate ligament ACL
prevent hyperextension
Menisci
medial meniscus
lateral meniscus
c-shaped fibrocartilage pads
reshape the tibial condyles for a better fit
absorb shock
Extracapsular Ligaments- found outside joint capsule
FIbular (lateral) collateral ligament LCL
tibial (medial) collateral ligament MCL
patellar ligament
Many Bursae
6-9 Major categories of Joints
General Structure of Synovial Joint- 5 distinct features
Joint cavity- a potential space between the two bones, filled with synovial fluid
Articular capsal- double layered capsule surrounding cavity
external, tough flexible fibrous capsil
synovial membrane- loose CT lining of fibrous capsule that also covers all internal joint surfaces excluding hyaline cartilage
Articular Cartilage- hyaline cartilage covers the surface of each bone
Synovial Fluid- viscous lubricating fluid within cavity
provide "weeping lubrication"
nourish cartilage
reduces friction between cartilages of 2 bones
contain phagocytes
Reinforcing Ligament- ligaments that strengthen joint
a ligament joins a bone to another bone across a synovial joint
usually thickened portions of fibrous capsule
Other Joint features:
Menisciorarticular discs or that separate cavity into 2 compartments (knee, jaw and sternoclavicular)
bursa- flattened fibrous sacs w/ a synovial membrane and fluid that act as "ball bearings" to prevent friction on adjacent structures during joint activity
cushion the movement of one body part over another
located between skin and bone and between muscle, tendons, ligaments, and bone
Fatty pads (hip and knee)
3 types of structural classification of joints based on material which joins bones between bones
Fibrous Joints- joints composed of fibrous tissue; no joint cavity is present
Gomphosis-tooth within its bony socket; short periodontal ligament
Stures- short fibrous CT fibers; synarthroses and only found in skull
Syndesmosis- cord of fibrous tissue called a ligament; amphiarthroses with "give" but no true movement
Cartiliginous- joints composed of cartilage; no joint cavity
Synchondrusis- a plate of hyaline cartilage
sites of bone growth during youth
eventually ossify= synarthrotic
EX: joint between the first rib and manubrium
EX: the epiphyseal plate
Symphysis- pad or plate of fibrocartilage
compressible "shock absorber"
limited movement= amphiarthroses
EX: intervertebral discs
symphysis pubis
Synovial Joint- fluid-filled joint cavity; free movement= diarthrosis
3 types of functional classification of joints based on amount of movement allowed
Amphiarthoses- slightly moveable joints EX: intervertebral discs between vertebrae
Diarthroses- freely moveable joints EX: joints of appendicular skeleton
Synarthroses- immoveable joints EX: sutures of skull
6-3 compare mechanism and intramembranous ossification and endochondral ossification
Introduction:
this skeleton provides supporting structures for ossification to begin
at about 6-7 weeks gestation, ossification begins and continues throughout adulthood
the skeleton of an embryo is composed of fibrous CT membranes that are loosely shaped like bones
Ossification follows one of two patterns:
both mechanisms involve the replacement of preexisting CT with bone
intramembranous ossification is when a bone forms on or within fibrous CT membrane
flat bones are formed in this manner
endochondral ossification occurs when a bone is formed from a hyaline cartilage model
primary ossification center hardens as fetus and infant
secondary ossification centers develop in child and harden during adolescence and early adulthood
most bones of the skeleton are formed in this manner
during infancy and childhood, long bones lengthen entirely by growth at the epiphyseal plates and all bones grow in thickness by a process called apposistional growth
growth at the epiphyseal plate
structure of the epiphyseal plate/disc (4 zones)
zone of priferating cartilage
larger chondrocytes that resemble a stack of coins
chondrocytes divide to replace those that die at the diaphyseal surface of the epiphysis
zone of hypertrophic cartilage
extremely large chondrocytes that are arranged in columns
maturing cells
zone of resting cartilage
small, scattered chondrocytes
anchor plate to epiphysis
near epiphysis
zone of calcified cartilage
consists of dead cells because the matrix around them became calcified
this calcified matrix is destroyed by osteoclasts and is then invaded by osteoblasts and capillaries from the diaphysis
only a few cells thick
the osteoblasts lay down bone on the calcified cartilage that persists
as a result the diaphyseal border of the plate is firmly cemented to the bone of the diaphysis
The epiphyseal plate allows for bone lengthening until adulthood as a child grows
they are then destroyed and replaced by bone on the diaphyseal side of the plate
therefore, the thickness of the plate remains almost constant while the bone on the diaphyseal side increases in length
cartilage cells are produced by mitosis on the mitosis on the epiphyseal side of the plate
the rate of bone growth is controlled by
human growth hormone from the pituitary
sex hormones from the gonads
The rate of ossification of most bones is completed by 25
The cartilage of the epiphyseal plate is replaced by bone forming the epihyseal line
appositional growtt- along with increasing in length, bones increase in thickness or diameter
osteoblasts lay down matrix (compact bone) on outer surface
this accompanied by osteoclasts destroying the bone matrix at the endosteal surface
occurs in osteogenic layer of periosteum
6-5 the effects of the aging process on the skeletal system
Age related skeletal changes are apparent at the cellular and whole body level
bone loss gradually exceeds bone replacement
after menopause, females lose bone more rapidly than males
by age 70 bone loss between sexes is similar
fractures increase as bones age
height begins to decrease incrementally at around age 33
Osteopenia
Osteoporosis
affects normal function
over age 45: occurs in 29% of women and 18% of men
because less estrogen being produced
after menopause the risk goes up
less common in under 60 because of androgens are still produced
severe bone loss
Types of Fractures:
cracks or breaks and bones, and caused by physical stress
comminuted- completed and fragments the bone
transverse- complete at the right angle to the bone
fissured- incomplete longitudinal break
oblique- complete at an angle other than right
greenstick- incomplete convex surface of the bend
spiral- complete caused by excessive twisting
open and closed:
6-8 Appendicular Skeletal Organization
Appendicular Skeleton includes the limbs of the upper and lower extremities and the bones that attach those limbs to the trunk (pectoral & pelvic girdles)
Pectoral Girdle- connects the upper limbs to rib cage and consists of two pairs of bones
anterior clavicle (2)= collar bones
lateral acrominal end
provide attachments for many muscles
medial sternal ends
posterior scapulae (2)= shoulder blades
acromion= uppermost point of shoulder
spine= diagonal posterior surface
body= flattened triangular region
medial & lateral border
coracoid process= anterior projection of superior portion (looks like a bent finger); attachment for biceps muscle
glenoid cavity (fossa)= small fossa that articulates with the head of the humerus
flattened, triangular bones
inferior angle
Humerus= upper arm bone
typical long bone
deltoid tuberosity
body
greater/lesser tubercle
medial/lateral epicondyles
distal capitulum and trochlea
olecranon fossa
proximal head
Radius= forearm bone on same side as thumb
radial tuberosity
ulnar notch
neck
styloid process
head
Ulna= forearm bone on same side as pinky
trochlear notch= receives trochlea of humerus
coronoid process
head (distal)
styloid process (medial prominence)
olecranon (process)= prominence of elbow