EXS 331 Exam 2

Dr. Shawn Magrum

chondro

referring to cartilage

osteo

referring to bone

hyaline, fibro, elastic

types of cartilage

chondroblast function

produce matrix

chondrocytes

cartilage cells surrounded by matrix that occupy lacunae

interstitial growth

growth from within the cartilage

appositional growth

growth from along the cartilage periphery

4 steps of interstitial growth

1. mitosis of chondrocytes in lacunae

2. forms two chondroblasts per lacuna

3. each synthesizes and secretes new matrix

4. cartilage continues to grow as new matrix is produced from within

results of interstitial growth

larger piece of cartilage with newest on the inside

3 steps of appositional growth

1. mitosis of stem cells deep to perichondrium

2. stem cells become chondroblasts at periphery

3. chondroblasts produce matrix and become chondrocytes in lacunae

appositional growth results

larger piece of cartilage with newest on the outside edges

calcification

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functions of the bone

support and protect organs, enable movement, store minerals and energy, produce RBC

long bones

bones that are longer than they are wide

upper and lower limb bones

long bone examples

short bones

bones that are as long as they are wide

carpals and tarsals

short bone examples

flat bones

bones that are thin and flat

roof of skull and sternum

flat bone examples

irregular bones

complex shaped bones

vertebrae

irregular bone examples

diaphysis

elongated, cylindrical shaft of long bone

epiphysis

knobby, enlarged regions at each end of long bone

metaphysis

region between diaphysis and epiphysis

epiphyseal plate or epiphyseal line

contained in the metaphysis

articular cartilage

thin layer of hyaline cartilage covering the epiphysis

medullary cavity

hollow, cylindrical space in diaphysis

articular cartilage function

reduce friction and absorb shock in moveable joints

in the medullary cavity

yellow bone marrow with extra adipocytes to store excess energy

endosteum

thin membrane lining most internal surfaces of bones

osteoprogenitor cells, osteoblasts, osteoclasts

cells contained in endosteum

bone remodeling, growth, and fracture repair

endosteum function

periosteum

dense irregular connective tissue that covers external surfaces of bones except for where the joints articulate

perforating fibers

attach periosteum

periosteum function

anchor for blood vessels and nerves

osteoprogenitor cells and osteoblasts

cells contained in the periosteum

osteoprogenitor cells

mesenchymal stem cells in endosteum and periosteum

osteoblasts

form bone matrix as organic osteoid

osteocytes

maintain matrix and detect mechanical stress on a bone

osteoclasts

large, multinuclear cells that dissolve bone matrix and release calcium that makes the bone rigid via bone reabsorption

osteoclasts function

secrete hydrochloric acid and enzymes that dissolve matrix

cells, collagen fibers, ground substance

organic components of bone matrix

hydroxyapatite and hydroxide

inorganic components of bone matrix

hydroxyapatite

calcium phosphate and calcium

hydroxide

provides compressional strength

compact bone definition

solid and relatively dense bone

compact bone location

external surfaces of long and flat bones

spongy bone definition

open lattice of narrow places called trabeculae

spongy bone location

internal surfaces of bone

diploe definition

spongy bone in between two layers of flat bone

osteon

basic unit of compact bone that consists of cylindrical structures that run parallel to diaphysis

central canal

carries vessels and nerves in center of osteon

concentric lamellae

rings of bone around central canal

osteocytes

housing in lacunae between lamellae

canaliculi

tiny interconnecting channels that extend between lacunae and allow osteocytes to connect and ocmmunicate

perforating canals

canals that run perpendicular to and help connect multiple central canals that serve as passageways for blood vessels and nerves

circumferential lamellae

rings of bone immediately internal to the periosteum or the endosteum

interstitial lamellae

leftover parts of resorbed osteons

microscopic anatomy of spongy bone

network of trabeculae that provides resistance to stresses applied in many directions

ossification

formation and development of bone connective tissue

intramembranous ossification

produces flat bones of the skull, some facial bones, mandible, and central portion of clavicle

messenchyme

intramembranous ossification develops from this

endochondral ossification

produces most of the rest of the bones in the body such as the upper and lower limbs

hyaline cartilage model

endochondral ossification develops from this

intramembranous ossification steps

1. ossification centers form within thickened regions of messenchyme

2. osteoid undergoes calcification

3. woven bone and surrounding periosteum form (rough draft)

4. lamellar bone replaces woven bone as compact bone and spongy bone form

process in step 2

osteoblast entombed in matrix and become osteocyte and ossification center expands

process in step 3

new capillary entering and bone forms around them and mesynchymal cells will differentiate into periostium