Anatomy Chapter 7: Bone Tissue
hematoma & granulation formation
broken vessels form a blood clot pool from granulated tissue
blast
build, bud, germ
bone
calcium and blood
canal
canal, channel
endosteum
capsule
lacunae
cavity, space for osteocytes
zone of hypertrophy
cell enlargement - gets bigger.
canaliculi
channels, provide nourishment, bristles on a brush, connect the osteocytes, bone cell
zone of proliferation
chondrocytes multiply forming columns of flat lacunae
fractures
classified by their structural characteristics - causing a break in the skin, breaking into multiple pieces, etc. or after a physician who first described it
resorption bays
where osteoclasts reside that they have eaten into the surface of the bone (so they can dissolve bone cells)
calcitriol & PTH
which hormones respond to correct hypocalcemia
intra
within
gelatinous marrow of old age
yellow marrow replaced with reddish jelly
calcium, vitamin D boost limits stress fractures
young women benefit from high-than-suggested doses, navy study shows
other factors affecting bone
20 or more hormones. vitamins & growth gactors not well understood. bone growth especially rapid at puberty. hormones stimulate proliferation of osteogenic cells and chondrocytes in growth plate. adolescent girls grow faster than boys & reach their full height earlier (estrogen has stronger effect), males grow for longer time. estrogen vs testosterone. hormonally affected
tension/bending
<=== ===>
compression
===> <====
osteoporosis 2
estrogen replacement therapy (ERT) slows bone resorption, but best treatment is prevention - exercise and calcium intake (1000 mg/day) between ages 25 and 40. no cure - can slow its progression but not reverse it. exercise needs to be limited. therapies to stimulate bone deposition are still under investigation.
compact bone is replaced
every 10 or so years
spongy bone is replaced
every 3 to 4 years
compact bone
external and internal surfaces of flat bone are composed of
example of trabeculae
femoral head, laid down extra of this where extra stress is. includes yellow bone marrow
trabeculae
few osteons or central canals. no osteocyte id far from blood or bone marrow, bathed in blood/bone marrow
soft callus
fibrous tissue formed by fibroblasts & infiltrated by capillaries
4 main bone shapes
flat, irregular, long and short
sarc
flesh
ossification
formation of bone, also called OSTEOGENESIS
poietic
forming
myositis ossificans
from a severe hematoma incorrectly treated, develop over time, inflammation of a muscle that becomes ossified. defecit - lose strength. depositing of bone within muscles (Ca++ deposits), mesenchymal stem cells can become bone, cartilage, fat and even muscle. lay down bone in muscle. in severe cases, muscles of the neck, back and upper limbs may become bone (starts as calcium deposits)
FALSE
the role of both calcitriol and calcitonin is to lower blood calcium levels
false
the sphenoid bone is an example of a flat bone
bone tissue overview
tissues and organs of the skeletal system, histology of osseous tissue, bone development, physiology of osseous tissue, bone disorders & healing
function of parathyroid hormone (PTH)
to raise blood Ca++ levels by 4 ways: 1) binds to osteoblasts causing them to release osteoclast-stimulating factor that stimulares osteoclast multiplication & activity 2) promotes calcium resorption by the kidneys 3) promotes calcitriol synthesis in the kidneys 4) inhibits collagen synthesis and bone deposition by osteoblasts (slow down osteoblastic activity) increase osteroclastic activity, resorption from bone to blood
periosteum
tough fiber, velcroed to bone
periosteum
tough fibrous outer covering of whole bone
true
trabeculae means "little beams" and is developed along lines of stress
meta
transition zone
oma
tumor
flat bones
unique in shape in their arrangement of spongy and compact bone
epi
upon
electrical stimulation & ultrasound
used on fractures that take longer than 2 months to heal (non-union Fx) keep where it is supposed to be. couple days faster, not a couple weeks faster
exercise for your bone health
vital at every age for healthy bones, exercise is important for treating and preventing osteoporosis. not only does exercise improve your bone health, it also increases muscle strength, coordination, and balance. and leads to better overall health.
calcitriol, calcitonin, parathyroid hormone
vital homeostasis regulated by 3 hormones. it's about what the blood needs, bone needs, bone does
18-25
what age should you build up bone the most
histology of compact bone
what pathologists look at under microscope. medullary cavity, blood vessels and nerves
blood vessels and nerves
what structure (s) pass right down the center of the osteon
function of calcitriol
increase blood Ca++ {conc}, increased Ca++ REsorption (taking it out, withdrawals), small intestine, skeleton and kidneys and sent to the blood (pull back calcium)
bones make up the skeletal system
individual bones are made up of bone tissue, marrow, cartilage & periosteum
itis
inflammation
growth and healing
inner osteogenic layer important for
2 methods of bone development in fetus and infant
intramembranous ossification (within, fibrous) and endochondral ossification (within cartilage)
True
intramembranous ossification only forms a couple of bones because endochondral ossification forms all the rest
flase, very common
it is uncommon for certain bones in the right leg to be bigger and more dense that the same bones in the left leg
articular cartilage (hyaline)
joint surface covered with strong/rigid/firm _______________
periosteum (2)
layer around bone, layer around articular cartilage
more wolff's law
long bones are thickest {midway along diaphysis}, curved bones are thickest where tend to buckle, trabecula form struts along lines of compression, large bony projection occure where heavy active muscles attach, all match the demands placed upon it. bone - meets demand. if you don't use it you lose it.
healing of fractures
look at packet
types of bone fractures
look on packet
cells of osseous tissue
osteogenic cells (fibroblasts), osteoblasts, osteocytes (osteon, medullary cavity), stem cells, osteoclasts
stress fractures
pathological fracture. chronic overuse fractures that are caused by imbalance in minerals
perforating (Sharpey's) fibers
penetrate the periosteum
bone remodeling
performed by hormones x3, mechanical and gravitational forces (wolff's law)
general features of a long bone
periosteum and articular cartilage, compact bone, spongy bone, medullary or marrow cavity, yellow marrow, endosteum, nutrient foramen
perforating (volkman's) canals
perpendicular, cross matrix and feed intro central canals
25% mortality rate
post hip fracture, fatal complications such as pnemonia, blood clots, et al. die because of complications/diseas. widow's (dowager's) hump is deformed spine (kyphosis) hunchback due to bone thinning.
endochondral ossification
primary method of how bones are made. start off as cartilage. has a cartilage phase that IMO did not have. most bones develop from this process. 6 step process with many details but just overview at this point. cartilage to bone.
stage 2 & 3
primary ossification center and primary marrow cavity. start to ossify outer layer of cartilage. osteoclasts take over osteoblasts. 2) formation of primary ossification center, bony collar, and periosteum. 3) secondary ossification center gains length, perforating canal - blood supply. vascular invasion, formation of primary marrow cavity, and appearance of secondary ossification center
osis
process
genesis
produce, origin
closed reduction
put it back in. fragments are aligned with manipulation & casted by MD.
long bones
radius, ulna, femur
every week
recycle 5-7% of our bone mass
fetal skeleton at 12 weeks
red = cartilage, very soft
periosteum
remainder of bone covered in this. nerve fibers that protect epiphyses. velcro. outer fibrous layer of collagen fibers continuous with tendons. do not have it under articular cartilage
a complete osteoporosis program
remember, exercise is only one part of an osteoporosis prevention or treatment program. like a diet rich in calcium and vitamin D, exercise helps strengthen bones at any age. But proper exercise and diet may not be enough to stop bone loss caused by medical conditions, menopause, or lifestyle choices such as tobacco use and excessive alcohol consumption. it is important to speak with your doctor about your bone health. discuss when you might be a candidate for a bone mineral density test. if you are diagnosed with low bone mass, ask what medications might help keep your bones strong
the metaphysis
reserve cartilage, osteoblasts.
osteogenic cells
reside in endosteum, periosteum or central canal. arise from fibroblasts and become only source for new osteoblasts. multiply continuously & differentiate into amitotic osteoblasts in response to stress or fractures
minerals
resist compression
collagen
resists tension
flat bone
scapula, sternum
stage 4-6
secondary ossification centers and secondary marrow cavities. trabeculae, spongy bone, secondary marrow cavity at BIRTH. 4) bone at birth, with enlarged primary marrow cavity and appearance of secondary marrow cavity in one epiphysis BIRTH 5) CHILDHOOD. one big area, bone of child, with epiphyseal plate at distal end. epiphyseal plate is still cartilage. 6) skeletally mature, periosteum on outside, mature skeletal bone. adult bone with a single marrow cavity and closed epiphyseal plate
diaphysis
shaft. cylinder of compact bone, contains marrow cavity (medullary cavity) which is lined with endosteum
intramembranous ossification
(not all effort), produces flat bones of skull and clavicle only. fibrous membrane develops DIRECTLY into bone. forming a bone from a fiber - creating calcification. diploe - trabeculae in between 2 layers
4 step process of intramembranous ossification
1) mesenchyme condenses intro a sheet of soft tissue and eventually will become the periosteum (transforms into a soft network of trabeculae) 2) osteoblasts gather on the trabeculae to form osteoid tissue (uncalcified bones) calcium phosphate is deposited in the matrix transforming the osteoblasts into osteocytes, periosteum is now formed 3) osteoclasts remodel the center to contain marrow spaces and the ends continuing forming trabeculae 4) osteoblasts remodel the surface forming compact bone ("honeycomb sandwich" is formed!)
each day
1/2 gram of calcium may leave or enter the skeleton
osteomalacia
ADULTS. can't control. adult form of rickets. dwarfism - poor mineralization/matrix. bones softened and deformed. inadequate mineralization from poor nutrition (poverty) and many pregnancies, implication - high rate of fracture
osteoblasts
BONE BUILDERS. form and help mineralize organic matter of matrix (dense tissue)
osteocytes
BONE CELL. are former osteoblasts that have become trapped in the matrix they found. make deposits to make bones stronger to adapt to stress
osteoclasts
BONE DESTROYERS. develop in bone marrow by the fusion of 3-50 of the same stem cells that give rise to monocytes found on blood. bone is stronger with deposits, weaker with withdrawals.
remodeling
breaking down and building up
rickets
KIDS. many causes, they bow. can't control. child form of osteomalacia, epiphyseal plates cannot be ossified, implications - bones do not grow, dwarfism and deformed bones.
the metaphysis transitional zone
between head and shaft of developing long bone - 5 zones
dia
across
physiology of bone tissue
always remodeling, mineral deposits (primarily Ca++ and Pi) made when bone is injured or strength is needed. diet - proteins, vitamin C, D, A and several minerals (calcium) -bone resorption (dissolving) via osteoclasts
traumatic fracture
an acute break caused by abnormal trauma to a bone, from car accidents, falls, athletics, etc
homeostasis - physiology of bone tissue
as many depositions as withdrawals. bone remodeling is based on the amount of Ca and Pi deposition vs. their resorption. bone is the reservoir for Ca++ and Pi. Therefore, calcium and phosphate homeostasis is vitally important. for muscle contraction, blood clotting, nerve communication, etc. depends on dietary intake, waste removal, and mineral exchange
secondary ossification centers
begin to form in the epiphyses near time of birth. same stages occur as in primary ossification centers. results in center of epiphyseal cartilage being transformed into spongy bone. hyaline cartilage remains on. joint surface as articular cartilage, junction of diaphysis & epiphysis (epiphyseal plate). each side of epiphyseal plate has a METAPHYSIS.
healthy trabeculae
better than thinning, osteoporotic trabeculae
emia
blood
heme/o
blood
acid-base balance
blood buffer, homeostasis
hemopoesis
blood formation, where blood is made
haversian (central) canal
blood vessels and nerves pass. felt - blood vessels
histology of compact bone
blood vessels and nerves. calcified matrix is concentric lamellae around central (haversian) canal containing blood vessels & nerves. osteocytes in lacunae between lamellae connected by canaliculi. osteocytes are housed in lacunae. physical support, leverage for muscles, mineral storage
blood vessels of compact bone
blood vessels outside bone --> inside
os, osse
bone
osteo
bone
calcification
bone (osseous tissue) is CT with a matrix hardened by minerals (calcium phosphate)
absorb
bone builder, to deposit, increase bone
osteocyte
bone cells
cells of osseous tissue
bone in constantly remodeled (built up and broken down) all life long. this remodeling is a delicate balance of osteoblastic and osteoclastic activity based on needs of the body (body needs to make up for withdrawals)
physiology of bone tissue
bone is a dynamic and active tissue all life long. small scale changes in architecture happen continually.
osteoporosis (porous bones)
bone mass decreases over time, bones thin as we age. brittle bone disease - bone thinning. most common bone disease. bones lose mass and become brittle due to loss of both organic matrix and minerals. (matrix weakening) risk of fracture of hip, wrist and vertebral column. postmenopausal white women at greatest risk. by age 70, average loss of estrogen
inorganic matter
bone salts/minerals, hard substances, skeletal remains. 85% hydroxyapatite (crystallized calcium phosphate salt) 10% calcium carbonate, other minerals (fluoride, sulfate, potassium, magnesium)
bone growth and remodeling
bones grow and remodel themselves throughout life. constantly breaking down and building up. active people - stronger, denser bones. athletes or active adults have greater density & mass of bone. bone grows by both appositional and interstitial growth from actually the cartilage within the bone. bones increase in length by institial growth of epiphyseal plate (moving) open vs. closed growth plates.
bone growth and remodeling
bones increase in width by appositional growth. wider, bigger circumference. -deposition of new bones at surface -osteoblasts lay down matrix in layers parallel to the outer surface & osteoclasts dissolve bone on inner surface -bone marrow cavity also widens (larger medullary cavity) if one outpaces the other, carious bone deformities can occur (Paget disease, osteoporosis, etc)
pathological fracture
break in a bone weakened by some other disease. bone cancer, osteoporosis, et al. osteoclasts winning the battle.
false
collagen resists compression forces while minerals resist tension forces
lamellae
concentric rings
cells in lacunae (hang out around osteocytes)
connected by gap junctions inside canaliculi. signal osteoclasts & osteoblasts about mechanical stresses
dynamic tissue
continually remodels itself
compact bone
dense, strong tissue. connect together, staggered, stacking. contains: haversian (central) canal, perforating (volkman's) canals, canliculi, lacunae, lamellae, osteocyte
epiphyseal plate or line
depends on age, child, adult. cartilage allows bone to grow.
zone of bone deposition
deposit/lay down/build into skeleton. chondrocytes die and columns fill with osteoblasts. osteons formed and spongy bone is created.
di
diameter
yellow marrow
diaphysis of long bones, fatty marrow of long bones in adults.
locate on a diagram: PRACTICE!
diaphysis, epiphysis, medullary cavity, osteon, central canal, lamellae, periosteum, endosteum, lacuna, canaliculi, osteocyte, volkman's or perforating canals, spongy bone, compact bone, articular cartilage
spongy bone
diploe. middle layer. no marrow cavity. compact but very strong. sponge, compact. blow to the skull may fracture outer layer and crush diploe, but not harm inner compact bone
matrix of osseous tissue
dry weight is 1/3 organic and 2/3 inorganic matter. combination provides strength and resilience.
proximal and distal epiphyses
ends. enlarged ends, spongy bone covered with layer of compact bone, enlarged to strengthen joint & provide for attachment of tendons and ligaments
growth ceases when
epiphyseal plates "close". anabolic steroids may cause premature closure of growth plate producing short adult stature.
fiberglass
glass fibers embedded in a polymer - very strong. bone adapts to tension and compression by varying proportions of minerals and collagen fibers.
physis
growth
appositional
growth in diameter
interstital
growth in length/height
in late teens, early 20s
growth plates begin to close in different bones (cartilage depleted and replaced with spongy bone - now called epiphyseal line)
long bones
have the most features associated with them
calcitonin
helps with HYPERCALCEMIA. gets rid of excess calcium in the blood. secreted by thyroid gland when CA++ {conc} rises too high in blood. important role in children, but little effect in adults. deficiency is not known to cause any disease in adults. may be useful in reducing bone loss in osteoporosis?
calcitriol
helps with HYPOCALCEMIA. bring to WNL. formed from vitamin D produced by the skin - liver - kidney. acts as a hormone but is considered a vitamin. added to the diet, especially if you do not get enough sunlight.
skull fracture
hit to outer layer of skull. having this go into the brain is a lot worse.
support
hold up body, muscles
zone of reserve cartilage
hyaline cartilage (backups), spread out
cartilage to bone
in 18 years and 9 months
red marrow
looks like thick blood. only certain spots. (axial skeleton), where blood is made, mesh of reticular fibers and immature cells. hemopoietic, found in vertebrae, ribs, sternum, pelvic girdle, and proximal heads of femur and humerus in adults.
function of calcitonin
lower blood Ca++ {conc} by 2 ways: reduces osetoclast activity by as much as 70% in 15 minutes. inhibit osteoclasts from breaking down bone. within an hour increases the number & activity of osteoblasts - build bone (deposit calcium from blood to bone)
zone of calcification
mineralization of matrix
body movement
muscles move bones for function
healing of fractures
normally healing takes 8-12 weeks (longer in elderly) stages of healing: replace with osteocytes (bone cells) -hematoma & granulation formation -soft callus -hard callus -remodeling
intramembranous ossification picture
not particularly on exam, but know concepts
traction
not used in elderly due to risks of long-term confinement to bed, otherwise cast immobilization, hip fractures are pinned & early ealking encouraged. 25% die within first year
remodeling
occurs over next 6 mo as spongy bone is replaced with compact bone
False
once bone is done forming, it does not continually grow or remodel at all
true
one of the important functions of bone is to maintain the homeostasis of the blood by making sure it does not become acidic or alkaline
protection
organs, vertebrae protects spinal cord
parathyryroid hormone (PTH)
similar to calcitriol, helps with HYPOCALCEMIA. secreted by the parathyroid glands. released when blood Ca++ {conc} level is too low, a 1% drop in blood calcium will double the amount of PTH secreted. injection of low levels of PTH can cause bone deposition
clast
smash, destroy
risk factors of osteoporosis
smoking, diabetes, poor diet in Ca++, vitamin C & D, et all.
felt inside marrow
so marker doesn't leak
hard callus
soft callus of fibrocartilage replaced by hard callus of bone in 6 weeks (temporary splint)
bone marrow
soft tissue that occupies the medullary cavity of a long bone or the spaces in the trabeculae of spongy bone.
wolff's law
specific adaptation to imposed demands. stress on tissue, will either adapt or fail/die. bone accomodates the forces applied to it by altering its amount and sitribution of mass (SAID principle) PERFECT example of Form of the bone follows functional experience. So, is bone the same everywhere in the body? (Greater trochanter - larger vs. Greater tubercle)
S.A.I.D
specific adaptations to imposed demands
irregular bones
sphenoid bone (holds pituitary gland), vertebrae, miscellaneous
histology of spongy bone
spongelike appearance formed by rods and plates of bone called trabeculae - keyword = little beams, spaces filled with red bone marrow. parasbone, empty space
trabeculae provides
strength with little weight, develop along bone's lines of stress, diploe. between two layers of compact bone.
TRUE
stress fractures are the result of a loss of homeostasis of osteoblastic and osteoclastic activity
osteon
structural unit, elongated cylinder
osteology
study of bone
dental x-rays can spot osteoporosis
study suggests simple, inexpensive way to detect bone-thinning disease
matrix
substance between cells in bones that is solid. it is calcified
10-15 min a day
sunshine for vitamin D
skeleton
support, protection, body movement, hemopoeisis, and mineral storage
functions of the "bony" skeleton
support, protection, body movement, hemopoiesis, mineral storage, acid-base balance
open reduction
surgically put it back together. surgical exposure & repair with plates, wires, screws, etc
step 1
synthesis of the cartilage during development that will become a bone someday. producing ossification centers. 2 main parts of this whole process are the formation of the promary and secondary ossification centers. metacarpal in mom as fetus.
organic matter
synthesized by osteoblasts. soft stuff, non calcified. soft tissue. won't find in a dead person. collagen, glycosaminoglycans, proteoglycans, & glycoproteins
resorb/resorption
take away, destroy, withdraw, lose bone, less bone.
short bones
talus, capitate (carpal) bone
