bone cells

Question 1

bone forming cells

Answer 1

osteoblasts

Question 2

origin of osteoprogenitor

Answer 2

UMCS

Question 3

LM of osteoprogenitor

Answer 3

shape;small and spindle
nucleus;oval
cytoplasm;pale basophilic

Question 4

EM of osteoprogenitor

Answer 4

few organelles;mainly polysomes

Question 5

Function of osteoprogenitor

Answer 5

convert to osteoblast during bone formation

Question 6

origin of osteoblast

Answer 6

from osteoprogenitor cells

Question 7

site of osteoprogenitor and osteoblast

Answer 7

in cellular layer of perichondrium;lining haversian canals;in endosteum

Question 8

mention functions of osteoblast

Answer 8

Bone formation by;
1-secretion of osteoid(uncalcified organic component)
2-secretion of alkaline phosphatase enzyme
3-osteoblast+lacuna=osteocyte

Question 9

function of alkaline phosphatase enzyme

Answer 9

deposition of calcium salts from the blood into bone matrix (bone mineralization)

Question 10

LM pic of active bone cell

Answer 10

shape;cuboidal or columnar arranged in 1 row
nucleus;eccentric and pale
cytoplasm;deep basophilic with negative gogi image

Question 11

EM pic of active bone cell

Answer 11

ultrastructura features of protein synthesizing cells

Question 12

unit bone cells

Answer 12

osteocyte

Question 13

origin of previous cell

Answer 13

osteoblast entrapped in lacuna

Question 14

function

Answer 14

maintenance of bone matrix

Question 15

site

Answer 15

inside lacuna of bone matrix

Question 16

LM pic

Answer 16

shape;flattened cells with many processes
nucleus;deeply stained
cytoplasm;deeply basophilic

Question 17

EM pic

Answer 17

nucleus;more heterochromatic than osteoblast
nucleus;more heterochromatic than osteoblast
cytoplasm;moderate amount of organelles
-present within lacuna

Question 18

what is canaliculi

Answer 18

processes of osteocytes are present within minute places called canaliculi
-lacuna and canaliculi interact with eachother

Question 19

how do osteocytes get their nutrition

Answer 19

1-small amount of extracellular fluid(in the lacuna and canaliculi surrounding the cells and their processes
2-Gap junction connecting neighboreing osteocytes

Question 20

can nutrition of osteocytes occur through diffusion

Answer 20

NO

Question 21

Bone eating cells

Answer 21

osteoclasts

Question 22

origin

Answer 22

from blood monocytes

Question 23

function

Answer 23

bone resorption during osteogenesis

Question 24

site

Answer 24

Resorption bays or howships lacunae

Question 25

LM pic

Answer 25

shape;irregular outline
size;giant
nucleus;multinucleated(up to 50)
cytoplasm;deeply eosinophilic and vaculated

Question 26

EM pic

Answer 26

*has 2 surfaces;
1-smooth surface
2-ruffled surface towards the area of bone resorption
*Cytoplasm contains;
1-mitochondria and lysosomes
2-well developed golgi
3-vesicles and vacuoles

Question 27

mechanism of polarity of osteoclasts

Answer 27

1-smooth border away from area of resorption
2-ruffled border face resorption area
3-mitochondria and lysosomes,vesicles and vacuoles under the ruffled surface
4-nuclei towards the smooth surface

Question 28

function of polarity

Answer 28

1-Bone resorption(osteogenesis,bone growth and remodeling)
2-digestion of matrix proteins by collagenase enzyme
3-dissolution of hydroxyapatite crystals by acid phosphatase enzyme