Unit 4: Skeletal System

bone functions

support against gravity
leverage for muscles
protection of organs
blood cell production
storage of calcium & fat

how many bones are you born with?

350+

how many bones in an adult

206

bone composition

living cells & protein fibers - surrounded by Ca

matrix

2/3 of bone mass containing:
- 85% crystallized calcium
- 10% calcium carbonate
- 5% other minerals

protein fiber

1/3 of bone mass containing:
- collagen (majority)
- glycoproteins, fibrillin

how many types of cells in bones?

4

what kind of tissue is bone?

connective

periosteum

CT covering that joins w tendons & ligaments

are there veins & arteries in bone?

yes

where is bone marrow?

inside bone cavities

red marrow (hemopoietic tissue)

makes blood cells

where do children have red marrow?

nearly in every bone

where do adults have red bone marrow?

skull
vertebrae
ribs
sternum
pelvic girdle
proximal heads of humerus and femur

yellow marrow

fatty CT

what happens to red marrow as you age?

most turns into yellow marrow & no longer produces blood

bone shapes

long
short
flat
irregular
sesamoid

what are the types of cells in bones?

osteogenic
osteoblasts
osteocytes
osteoclasts

osteogenic cells

create osteoblasts

where are osteogenic cells found?

endosteum, periosteum, central canals

osteoblasts

create new bone

osteocytes

mature bone cells that maintain bone structure

osteoclasts

break down bony matrix and release minerals

where are osteoclasts found?

on the surface

compact bone

dense

osteon (haversian system?

basic functional unit w osteocytes around canals

spongy bone

lattice adds strength w/o mass

do spongy bones have a lot of osteons?

no only a few bcs no central canals

trabeculae

calcified matrix developing along bone's lines of stress

what are the spaces in spongy tissue filled w?

red marrow

flat bone

sandwich-like construction

what are both surfaces of flat bone covered w?

periosteum

ossification (osteogenesis)

replacing tissues with bone

intramembraneous

bone grows in membranes - baby's soft spots turn to bone

endochrondal

bone replaces cartilage - growth zone for elongation w age

turnover rate in children

100%

turnover rate in adults

10%

osteoporosis

loss of bone density

axial skeleton supports _________________ & encases ___________________.

central axis, viscera

sutures

immovable joints of the skull

foramina

allow blood vessels and nerves to enter/leave cranium

foramen magnum

(largest opening) where medulla oblongata projects out from skull

fontanels

newborn soft spots

hyoid fuses from ________________

3 bones in early adulthood

hyoid function

provides anchor point for muscles of tongue and neck

intervertebral discs

fibrocartilaginous rings that contain a jelly-like fluid

intervertebral discs function

bearing weight

thoracic cage function

protects the visceral organs

sternum made up of ________________

manubrium, body, xiphoid process

appendicular skeleton suspended from _________________

axial system

appendicular includes bones of
1. ________________
2. ________________
3. ________________

limbs, pelvis, shoulders

pectoral girdle components
1. ________________
2. ________________

clavicles, scapula

shoulder function

arm mvmt & articulation

humerus head articulates w _____________

scapula

distal condyle articulates w _____________

forearm

radius

lateral bone of the forearm (thick)

ulna

medial bone of the forearm (thin)

carpal bones

wrist bones

phalanges

fingers

pelvic girdle components

two coxae

femur articulates w _______________

patella

ankle has _______________ bones

7 taraal

foot components
1. _______________
2. _______________
3. _______________

calcaneous, metatarsal, phalanges

articulates are/are not between every 2 bones

are even if not mvpable

synarthrosis

held tightly together with tough fibers

amphiarthrosis

permits some mvmt thru cartilage

diarthrosis

freely movable w fluid filled cavities

synarthrosis types
1. ______________
2. _______________
3. _______________

suture, gomphoses, syndesmosis

gomphosis

attachment of tooth to socket

syndesmosis

bones connected by ligaments (fibrous joint)

amphiarthrosis types
1. _______________
2. _______________

synchondroses, sympheses

synchondroses

bones bound by hyaline cartilage

simphyses

bones joined by fibrocartilage

types of diarthrosis
1. _______________
2. _______________
3. _______________
4. _______________
5. _______________
6. _______________

gliding, hinge, pivot, ellipsoidal, saddle, ball&socket

bursae

shock absorbers

synovial fluid

lubricating fluid