chapter- 6Bones and Skeletal tissue

function of bones

attachment,blood cell formation,hormone production,support, protection

Support

holds up body, cradles organs

Protection

CNS (skull protects brain) , vertebrae wrap spinal cord

visceral organs

ribcage wraps around thorax upper ab cavity

reason for tissue in bones

calcium deposits

Stomach and liver protection

by ribcage

attachment points

skeletal muscle via skeletal muscle tendons

storage

minerals [calcium phosphate salts in bone fibers], fat ( yellow marrow)

Needs of muscle and nervous tissue

Ca+

Low calcium levels

Will take from blood

Blood cell formation

Hematopoiesis in red blood marrow, thrombocytosis

Hormone production

Osteocalcin to regulate insulin, glucose homeostasis

increase in insulin

because of increase in osteocalcin

initial cartilage formation

is better for rapid growth

cells of cartilage

chondroblasts

chondroblasts accommodate

accommodate mitosis

cartilage allows for

allows push-pull

high water causes

helps with flexibility

cartilage has how much water

80% water

cartilage supply

avascular, diffusion that limits thickness

cartilage is surrounded by

perichondrium

what is perichondrium

fibrous connective tissue, vascular

too much movement

hurt surroundings

not enough movement

limit flexibility

most common cartilage

hyaline

exception of hyaline

knee

characteristics of hyaline

collagen fibers

examples of hyaline cartilage

articular, costal, respiratory, nasal

elastic cartilage

elastic and collagen fibers, more flexibility

areas of elastic

external ear, epiglottis

fibrocartilage

rows of chondrocytes, lots of collagen, small matri

example of fibrocartilage

discs, knee, pubic symphysis

types of cartilage growths

appositional, interstitial

appositional growth

rings to trees, new cartilage on old, cells under perichondrium at surface of cartilage tissu

appositional growth causes

causes cartilage growth

interstitial growth

cells divide and secret matrix with pre-existing cartilage, deeper in cartilage tissue, push-pull, important for fetus

bone location

axial and appendicular

shape classification

long, short, sesamoid, flat, irregular

example of short bones

carpals and tarsals

sesamoid bone ex

patella in tendon from quad to tibia

flat bone ex

cranial bones, sternum, ribs, scapula, ribs

irregular bones

discs, hip

compact lamella ex

mouth

trabecular

lots of stress/push

arrangement of bone

compact, spongy, compact

no large cavities for

none for bone marrow

all bone marrow around

trabecular in spongy

long bones

structurally more complex to support

4 features of long bones

diaphysis, epiphysis, membranes, vascularization/innervation

diaphysis

bone shaft, compact bone collar with internal medullary cavity, bone marrow, high pressure, little blood supply

white vs yellow

depending on age

epiphysis

no medullary cavity, covered by articular, bone ends, tendons/ligaments attach

membranes

periosteum, endosteum

periosteum

fibrous membrane that covers compact bone except at epiphysis, vascularization, innervation

epiphysis breakage

will become weaker if broken too much

endosteum

covers internal bone, surface has trabecula in spongy bone, cavities in compact bone, osteoprogenitor

osteoprogenitor

stem cells of a specific bone

vascularization and innervation

high via artery/vein to serve long diaphysis, epiphyseal artery to serve epiphyseal

nerves travel with

with blood vessels

compact bone of lamellar bone

made by osteon, tight

lamellar bone prevents

bone breaking

central canal

run through each osteon, avascular

osteon

structural unit

perforating canals

extending from central canal to connect neighboring osteons and medullary cavity

types of lamellae

interstitial, circumferential

interstitial lamellar

incomplete lamellae between complete osteons

function of interstitial lamellar

fill gaps in osteons

circumferential lamellae

found deep to periosteum around diaphysis

function of circumferential lamellae

resist twisting long bone, run in opposite directions

hematopoietic tissue

red bone marrow to make red blood cells

location of red bone marrow in adults

skull, ribs, hips, sternum, clavicle, scapula, discs, heads of femur and humerus

location of red bone marrow in kids

everywhere

yellow marrow in adults

medullary cavities of long bone and in flat bones

reconversion

when enough rbc and o2

time of conversion

severe hemorrhage or anemia when healing

Fe3+ binds

binds with o2

4 main bone cells

osteoprogenitor, osteoblasts, osteoclasts, osteocyte

osteomalacia

decide what is most important: calcium vs vit D

low vitamin d

cannot accept calcium that makes bone

osteoprogenitor cells

mitotically active because are stem cells

osteoprogenitor cells lifecycle

active through life

osteogenic to

to osteoblasts

-blast means

immature cell

osteoblasts

unmineralized, lay ground substance and fibers with calcium phosphate salts

function of osteoblasts

secrete matrix until surrounded themselves with no more room

osteoblasts fill space

will turn to osteocyte

osteocyte

mature bone cell

function of osteocyte

maintain bone tissue and matrix thickness

osteocyte mitotic

not mitotic

osteocyte responds to

mechanical stress

osteocytes look

projections of cell membrane to communicate via touching to osteoblasts

osteoclasts

maintain, repair and remodel bones to produce collagenase

collagenase

enzyme to break down bone

calcium levels are low

stimulates osteoclasts

osteod

organic

inorganic

mineral salts ( calcium phosphate mostly)

bone formation name

endochondral ossification

endochondral ossification define

formation of ossified bone by replacement of cartilage with bone

location of endochondral ossification

most bones below skull

endochondral ossification process summary

ossified bone is laid down, hyaline cartilage is broken down