Skeletal System

Front 1

list the functions of the skeletal system

Back 1

1. support
2. protection
3. assistance in movement
4. mineral storage
5. blood cell production [hematopoiesis] in red marrow
6. energy [triglyceride] storage in yellow marrow

Front 2

list the different possible bone shapes and give an example of each

Back 2

1. long - humerus, femur, phalanges
2. short - carpals, tarsals
3. flat - sternum, cranial bones
4. irregular - vertebrae, mandible
5. sesamoid - patella, sometimes can form in tendons under stress
6. sutural [Wormian] - form between sutures of the skull sometimes

Front 3

describe the structure of a typical long bone

Back 3

diaphysis
metaphysis
epiphyses
articular cartilage [hyaline]
periosteum [surrounds bone, but is NOT bone tissue]
medullar cavity [yellow marrow]
endosteum -- lines medullary cavity

Front 4

list the types and functions of the 3 cells comprising bone tissue

Back 4

osteoblasts: bone forming; can't divide, secrete matrix, form osteocytes

osteocytes: mature bone cell; one per lacuna

osteoclasts: bone-reabsorbing, form from monocytes

Front 5

contrast the structure of spongy vs compact bone

Back 5

spongy-- most bone tissue except the outer layer is spongy, interlaced trabeculae [bony plates], irregular lacunae with osteocytes, red marrow between, compressible

compact-- outer layer + diaphysis in long bones, less compressible, provides protection and support, cells arranged in Haversian Systems

Front 6

describe the structure of a Haversian system

Back 6

Haversian [central] canal in the center: nutrients, wastes to osteon [blood and lymphatic vessels]

surrounding that are lamellae [rings of lacunae-- one osteocyte in each]

canliculi-- interconnect lacunae and Haversian canal

Front 7

list and contrast the 2 types of bone formation

Back 7

1. endochondral ossification: bone replaces hyaline cartilage, happens with most bones
chondrocytes [cartilage cells] divide, hypertrophy [enlarge], and die
blood brings osteoblasts
osteoblasts secrete matrix--- Golgi complex secretes mucopolysaccharides & endoplasmic reticulum secretes collagen (protein) fibers]
calcification -- hardens matrix [deposits Ca++ salts]




2. intramembranous ossification: replaces fibrous connective tissue membrane

begins at ossification center [only one!] right at the center of the membrane

steps: same as endochondral ossification, except we're replacing fibrous connective tissue, not cartilage!

blood brings osteoblasts
osteoblasts secrete matrix
calcification

Front 8

describe how a bone grows in length

Back 8

occurs at epiphyseal disks [hyaline cartilage]; chondrocytes divide, hypertrophy, and then die--> ossification; bones elongate until cartilage is totally replaced by bone

Front 9

describe how a bone grows in diameter

Back 9

ossification at periosteum by osteoblasts
reabsorption at endosteum by osteoclasts