6.3 Bone Histology Flashcards Preview

Bio 364 Lecture Exam 1 > 6.3 Bone Histology > Flashcards

Flashcards in 6.3 Bone Histology Deck (27):
1

what is the bone matrix?

non-cellular/interstitial organic and inorganic material

2

what are the 3 main components of bone matrix?

hydroxyapatite (Ca++ PO4) inoranic, 65%
collagen and proteoglycans, organic material

3

what are the 3 types of bone cells?

osteoblasts
osteocytes
osteoclasts

4

what do osteoblasts do?

make new matrix: make organic material and help lay down Ca++ and PO4 that can combine to make mineral matrix
for growth repair and development
i.e. ossification/osteogenesis

5

when does an osteocyte form?

once an osteoblast becomes surrounded by matrix

6

what do osteocytes do?

less active than osteoblasts, just maintain matrix

7

where do osteocytes live?

lacunae and extensions of cytoplasm in canaliculi

8

what is the purpose of the cell-to-cell connections of the osteocytes and where are they located?

located in canaliculi
nutrients and gases move by diffusion from cell-to-cell

9

describe an osteoclast

multinucleated
responsible for bone breakdown/resorption

10

how do osteoclasts work and when do they work?

use H+ (acid to decalcify) and enzyme to digest proteins in the matrix
used to resculpt bone (as in a break or growth) or to release Ca++ for bl Ca++ levels

11

what is the origin of an osteoclast?

marrow

12

what is the origin of an osteocyte?

mature form of osteoblast

13

what is the origin of an osteoblast?

osteochondral progenitor cells

14

where are osteochondral progenitor cells located?

inner layer of periosteum
inner layer of perichondrium
endosteum

15

describe woven bone

woven bone is the temporary bone of the fetal skeleton or repaired areas
random arrangement of collagen

16

describe lamellar bone

replaces woven bone in mature bone
organized arrangement of sheets of bone and fibers (osteon)

17

what is the organizational unit of lamellar bone?

lamella arranged in osteons

18

what is a lamellae?

the matrix organizational unit of lamellar bone
thin sheets of mature bone matrix in which the collagen fibers lie parallel to each other

19

what is the arrangement of collagen fibers in lamellar bone?

parallel within the lamella but at an angle to the arrangement in adjacent lamellae

20

describe an osteon

a blood vessel within a central canal surrounded by concentric lamellae (sheaths of matrix)
layers of osteocytes connected by cannaliculi

21

what fills in between the circular osteons?

interstitial lamellae

22

what fills in the space between osteons on the periphery of the bone (just underneath the periosteum)

circumferential lamellae

23

what are the 2 types of mature lamellar bone?

cancellous (spongy) and compact

24

describe cancellous bone

contains a lot of "space"
aka spongy bone
made of interconnected trabeculae
spaces filled with marrow, vessels

25

describe trabeculae

the "beams" of cancellous bone
alternating layers of lamella and osteocytes
"exposed" surfaces covered with osteoblasts

26

describe compact bone

dense lamellar formation
osteon is functional unit

27

Draw a long bone

Do it