Anatomy Chapter 7: Bone Tissue

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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


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