MICROSCOPIC ANATOMY OF BONE

Question 1

OSTEON(HAVERSIAN SYSTEM)

Answer 1

-a unit of bone contains central canal & matrix rings
CENTRAL (HAVERSIAN) CANAL
-opening in the center of an osteon
-carries blood vessels & nerves
PERFORATING (VOLKMANS) CANAL
-canal perpendicular to central canal
-carries blood vessels & nerves

Question 2

LACUNAE

Answer 2

-cavites containing bone cells(osteeocytes)
-arranged in concentric rings

Question 3

LAMELLAE

Answer 3

-rings around central canal
-site of lacunae

Question 4

CANALICULI

Answer 4

-tiny canals
-radiate from central canal to lacunae
-form a transport system connecting all bone cells to nutrient supply

Question 5

FORMATION OF HUMAN SKELETON

Answer 5

-in embryos, the skeleton is primarily hylaine cartilage
-during development, much of this carilage is replaced by bone
-cartilage remains in isolated areas
EX- bridge of nose, part of ribs, joints

Question 6

BONE GROWTH
(OSSIFICATION)

Answer 6

-epiphyseal plates allow for lengthwise growth of long bone during childhood
//new cartilage is continuously formed
// older cartilage becomes ossified
//cartilage is broken down
//enclosed cartilage is digested away, opening up a medullary cavity
//bone replaces carilage through the action of osteoblast
-bone are remodeled & lengthend until growth stops
-bones are remodeled in response to 2 factors
//blood calcium levels
//pull of gravity & muscles on the skeleton
-bones grow in width(appositional growth)

Question 7

TYPE OF BONE CELLS

Answer 7

osteocytes- mature bone cells
osteoblast- bone forming cells
osteoclast- bone destroying cells
//break down bone matrix for remembering & release of calcium in response to parathyroid hormone
-bone remodeling is performed by both osteoblast & osteoclast-