Chapter 6 Flashcards
what are bones
complex organs containing all four types of tissue cells
what are the tissues present in bone
blood, muscle, nervous, and epithelial tissue
what is the bone mainly comprised of
bone connective tissue
describe the extracellular matrix of the bone
sturdy and rigid
why is the ECM of the bone sturdy and rigid
due to the deposition of minerals
what is calcification
the process of the formation of mineral content and the deposition of Ca2+
functions of bone
- support
- protection
- movement
-hemopoiesis - storage of mineral and energy reserves
what is hemopoiesis
making of blood in medullary vacity of long bones
what are the classifications of bones
long bones
shirt bones
flat bones
irregular bones
long bones
greater length than width
short bones
nearly equal length and width
flat bones
thin surfaces
irregular bones
complex shapes
are are words to descripe the general structure and gross anatomy of long bones
diaphysis, epiphysis, metaphysis, articular cartilage, medullary cavity, endosteum, periosteum
diaphysis
elongated, cylindrical shaft
metaphysis
region between diaphysis and epiphysis
contains epiphyseal plate
what is an epiphyseal plate
a growth plate
articular cartilage
thin layer of hyaline cartilage covering the epiphysis
- reduces friction and absorbs shock in moveable joints
medullary cavity
hollow, cylindrical shape in diaphysis
- in a adults it contains yellow bone marrow
endosteum
covers most internal surfaces of bones
- contains osteoprogenitor cells, osteoblasts and osteoclasts
periosteum
- dense irregular connective tissue
- covers external surfaces of bones
acts as anchor for blood vessels and nerves - contains osteoprogenitor cells and osterblasts
what are the cells of bones
osteoprogenitor cells, osteoblasts, ostecytes, and osteoclasts
osteoprogenitor cells
mesenchymal stem cells found in endosteum and periosteum, can produce more stem cells or osteoblastsos
osteoblasts
form bone matris
osteocytes
reside in lacunae, mainting matrix and detect mechanical stress on a bone
osteoclasts
large, multinuclear cells taht dissolve bone matrix releasing Ca2+
composition of the bone matrix
organic componentsL cells, collagen fibers, ground substance
inorganic components: minerals (calcium, phosphate, etc)
how much of the bone matrix is inorganic compounds
depends on the type of bone but most are 2/3 inorganic compounds
compact vs spongy bone
compact: solid and relatively dense, external surfaces of long and flat bones
spongy bone: open lattic of narrow plates called trabeculae, internal surface of bones
flat bones within the skull
two layers of compact bone with spongy bone sandwiched between
what is the basic structural and functional unit of mature compact bone
the osteon
what is the osten also known as
- a haversian system where a cetnral haversian canal is surrounded by concentric layers of lamella
- cylindrical structures run parallel to the diaphysis
microscopic anatomy parts of the compact bone
- central canal
- concentric lamellae
- osteocytes
- canaliculi
- perforating canals
- circumferential lamellae
- interstitial lamellae
microscopic anantomy of the spongy bone
no osteons
trabeculae contains parallel lamellae
what is located in the center of the osteon
blood vessels and nerves
central canal
- the center of the osteon
- carries blood vessels and nerves
concentric lamellae
rings of bone around the central canal
osteocytes
housed in lacunae between concentric lamellae
canaliculi
- tiny, interconnecting channels within bone that extend between lacunae
- allows osteocytes to connect and communicate transmitting info like how much stress
perforating canals
- run perpendicular to and help connect multiple central canals
- passageways for blood vessels and nerves
circumferential lamellae
- rings of bone immediately internal to the periosteum or internal to the endosteum
interstitial lamellae
leftover parts of osteons that have been partially resorbed
ossification
the process of forming and devloping bone
what are the two patterns of ossification
intramembranous ossification
endochondral ossification
intramembranous ossification steps
- ossification centers from within thickened regions of mesenchyme
- osteoid undergoes calcification
- woven bone and surrounding periosteum forms (condensed mesenchyme cells)
- lamellar bone replaces woven bone, as compact bone and spongy bone form
endochondral ossification steps
- the fetal hyaline cartilage model develops
- cartilage calcifies and a periosteal bone collar forms
- the primary ossification center from in the diaphysis
- secondary ossifcation centers form in the epiphysis
- bone replaces cartilage, except the articular cartilage and epiphyseal plate
- epiphyseal plate ossify and form epiphyseal lines
interstitial growth
- long bone growth in length
- occurs in the epiphyseal plate
appositional growth
- growth in a bone’s diameter
- occurs in the periosteum and occurs by pushing the periosteum outwards creating a larger medullary cavity
what are the four major sets of blood vessels
nutrient artery and vein
metaphyseal arteries and veins
epiphyseal arteris and veins
periosteal arteries and veins
how do blood and nerves innervate the bones
through the nutrient foramen or other foramens
nutrient artery and vein
- supply the diaphysis of a long bone
- usually just one nutrient artery and vein per bone
metaphyseal arteries and veins
supply the diaphyseal side of the epiphyseal plate
epiphyseal arteries and veins
supply the epiphyses
periosteal arteries and veins
supply blood to the external circumferential lamellae and superficial osteon
what does bone growth, maintainence, and repair depend on
hormones
vitamins
exercise
effects of hormones
- hormones alter the rates of osteoblasts and osteoclast activity
- regulate calcium levels in the blood through calcitonin and parathyroid hormone
what does calcitonin do
deposits calcium from bloodstream to bone
what does PTH do
removes calcium from bones and brigns into the bloodstream (calcium resorption)
what are the effects of vitamins
needed for normal bone growth and maintenance
- activation of bone cells, synthesis of bone matrix, and absorption of necessary nutrients
what are the functions of Vitamin A
to activate osteoblasts
what are the functions of vitamin D
promotes absorption of calcium and phosphate into blood
- helps with calcification
effects of exercise
- mechanical stress stimulates an increase in bone density by increased osteoblast activity = stronger and thicker bones
what can slow or reverse loss of bone mass
weight bearing exercise
what are breaks in bones called
fractures
how long does healing take
a few months but could take longer depending on severity of break
what are the steps of fracture repair
- a fracture hematoma forms
- fibrocartilaginous (soft) callus forms
- bone (hard) callus forms
- bone is remodeled
what are the types of bone fractures
simple, compound, complete, linear, oblique,, spiral, transverse
simple fracture
bone does not break through the skin
compound fracture
broken ends of the bone protrude through the skin
complete fracture
bone is broken into two or more pieces
linear fracture
fracture is parallel to the long axis of the bone
oblique fracture
diagonal fracture at an angle between linear and transverse
spiral fracture
fracture spirals around the axis of long bone, results from twisting forces
transverse fracture
fracture at right angles to the long axis of the bone
condyle
large, smooth, rounded articulating oval structure
facet
small, flat, shallow articulating surface
head
prominent, rounded epiphysis
trochlea
smooth, grooved, pulley like articular process
fossa
flattned or shallow depression
sulcus
narrow groove
crest
narrow, prominent ridgelike projection
epicondyle
projection adjacent to a condyle
line
low ridge
process
any marked bone prominence
ramus
angular extension of a bone relative to the rest of the instruction
spine
pointed slender process
trochanter
massive, rough projection found only on the femur
tubercle
small, round projection
tuberosity
large, rough projection
cnaal
passageway through a bone
fissure
narrow, slitlike opening through a bone
foramen
rounded passageway through a bone
sinus
cavity or hollow space in a bone
what happens to the bone during the ageing process
- loses ability to produce organic matrix
- loses calcium and other minerals
osteoperosis
the decrease in bone mass
what is the value that is needed to deem someone as osteperotic
below 2.5 SD of the normal healthy adult bone density value
what is the value that is needed to diagnose someone with osteopenia
between 1.5-2.5 SD below the healthy bone density value in adults
what is a DEXA scan
a test used to measure bone mineral denity
types of osterorosis
Type 1 osteroporosis
Type II Osteoperosis
Type I osteroperosis
post menopausal osteoperosis
approx 40% of women over 50 are affected
Type II osteoperosis
age associated osteperosis
- after age of 60 90% of fractures due to osteoporosis
- men mainly affected at this age
