A&P Discussion U2Wk4&5: Skeletal System Introduction

fxns of bone (6)

support, protect, movement, reservoir, hematopoiesis, storage

living, dynamic tissue - always remodeling (building and breaking down)

bone

two major tissues of the skeletal system

bone, cartilage

highly vascularized CT with a hard, mineralized extracellular matrix

bone

protein fibers: what are they made of, organic or inorganic

collagen, organic

ground substance: what is it made of, organic or inorganic

hydroxyapatite crystals, inorganic

________ is a poorly vascularized C.T. with a matrix composed of chondroitin sulfate and various fibers

cartilage

3 major types of cartilage

hyaline cartilage, fibrocartilage, elastic cartilage

label A

epiphysis

label B

metaphysis

label C

diaphysis

Central cylinder of compact bone (“shaft”) with medullary cavity

diaphysis

enlarged end w/ compact and trabecular bone

epiphysis

b/t diaphysis and epiphysis; region of growth plate

metaphysis

• Layer of hyaline cartilage on articular surface of epiphyses

• Generic term for any cartilage between 2 bones

articular cartilage

Hollow central portion of diaphysis in large long bones; contains yellow marrow in adults

medullary (marrow) cavity

label top arrow (covers inner bone surfaces)

endosteum

label bottom arrow (covers outer bone surface)

periosteum

label blue arrows

compact bone

label yellow arrows

spongy bones

_______ bone is good at providing protection and support. Forms the superficial layer of all bones and shaft of long bones; made of layers called lamellae

compact

_______ bone is lightweight and provides tissue support. Fills the ends and internal spaces of long bones and is always found deep to compact bone.

spongy

______ are the fxn units of compact bone

osteons

________ ________ are rings of calcified matrix creating the osteon

concentric lamellae

_______ ______ b/t osteons are left over fragments of older osteons

interstitial lamellae

________ _______ lamellae encircle the bone beneath the periosteum.

outer circumferential

_____ ______ lamellae encircle the medullary cavity

inner circumferential

______ canals: transmits blood vessels and nerves

central (Haversian)

_____ canals: perpendicular channels connecting vessels and nerves

perforating

______: small spaces b/t the lamellae which house osteocytes

lacunae

_____: small channels filled w/ extracellular fluid connecting the lacunae

canliculi

Spongy bone lacks osteons. Instead, lamellae are arranged in a lattice of thin columns called ______

trabeculae

label cell

osteogenic cell

label cell

osteoblast

label cell

osteocyte

label cell

osteoclast

• Capable of degrading and reabsorbing matrix • Found on surface of any bone undergoing remodeling

osteoclasts

All connective tissues develop in utero from an embryonic connective tissue called ______

mesenchyme

Bone forms directly within mesenchyme (embryonic CT), arranged in sheet-like layers

intramembranous ossification

Most bones form this way

– The mesenchyme produces hyaline cartilage, which then forms the bone

– Causes growth of bones until 20s-30s; some don’t fully fuse until 50!

endochondral ossification

——— bones: greater in length than width; slightly curved for purpose of weight bearing (ex: femur, tibia, humerus, ulna, metacarpals)

long

_____ bones: cube shaped

short

_____ bones: thin, nearly parallel layers of compact bone enclosing a layer of spongy bone

flat

_____ bones have complex shapes

irregular

______ bones vary in # and protect tendons from excessive wear

sesamoid

_____ bones: extra bones b/t the plates of the skull - highly variable b/t individuals - not individually named

sutural

these surface markings allow the passage of blood vessels and nerves and form joints or provide space for muscle bellies

depressions/openings

these surface markings are projections/outgrowths that form joints and serve as attachment points for ligaments and tendons

processes

cleft, groove, or slit in bone

fissure

shallow depression

fossa

groove or furrow

sulcus

tube-like opening

meatus

smooth, eblarged end of bone on constricted neck

head

smooth, rounded articular surface, usually located o the epiphyseal ends of bones

condyle

small, fat, smooth articular surfac

facet

bony marking: prominent ridge

crest

bony markings: extension of bone marking an angle with the rest of the structure

ramus (rami)

bony markings: short projection of bone

spine

bony markings: thin, continuous ridge

line

trochanter(s)

swellings of bone of femur (greater, lesser)

bony markings: small, rounded projecting process

tubercle

bony markings: broad, roughened process

tuberosity

bony markings: spindle/pulley shaped articular surface (humerus)

trochlea

bony markings: prominence above a condyle

epicondyle

bony spaces: mucus-lined, air-filled cavity (cranial)

sinus

bony spaces: sockets in bone where teeth attach

alveolus

discussion 7