Histology: Bone (Exam 2)

Question 1

How is the connective tissue of bone characterized by

Answer 1

mineralized extracellular matrix

Question 2

What is the ECM of bone composed of

Answer 2

Hydroxyapatite crystals
Collagen I
Glycoproteins

Question 3

What glycoproteins are found in bone

Answer 3

osteocalcin
osteonectin
osteopontin

Question 4

What cells is bone composed of

Answer 4

osteocyte
osteoblast
osteoprogenitor cells
osteoclast

Question 5

What is the function of bone

Answer 5

support
protect
storage for calcium and phosphate

Question 6

What are the histological components of bone

Answer 6

bone tissue
hemopoeitic tissue
fat tissue
Dense CT
vessels
nerves
endosteum

Question 7

Where is hemopoeitic tissue found

Answer 7

in the red bone marrow in the epiphysis

Question 8

Where is fat tissue found

Answer 8

yellow bone marrow of the shaft

Question 9

Where is dense connective tissue found

Answer 9

outer fibrous layer of periosteum

Question 10

What are the fibers of the periosteum that extend into the bone called

Answer 10

Sharpey’s fibers

Question 11

What is the endosteum

Answer 11

covers the inner surface of the marrow cavity

Question 12

What cells are found in the endosteum

Answer 12

osteoprogenitor or endosteal cells

Question 13

What is the function of osteoprogenitor cells

Answer 13

differentiate into osteocytes

Question 14

What are the two types of bone

Answer 14

compact bone

spongy bone

Question 15

Where is compact bone found

Answer 15

within the shaft

Question 16

Where is spongy bone found

Answer 16

forming trabeculae

Question 17

What are the different classifications of bone, based on shape

Answer 17

long bone
short bone
flat bone
irregular bone

Question 18

What is a haversian lamellae

Answer 18

concentric lamellae surrounding a haversian canal

Question 19

What do the concentric lamellae surrounding a haversian canal form

Answer 19

cylindrical units called osteon or haversian systems

Question 20

What is the axis of the haversian system parallel with

Answer 20

the shaft

Question 21

What is contained within a haversian canal

Answer 21

vessels and nerves

Question 22

What is a Volkmann’s canal

Answer 22

horizontal canal leading from one haverian canal to another

Question 23

Where are osteocytes found

Answer 23

in lacunae between the lamellae

Question 24

What are canaliculi

Answer 24

hair like canals that connect lacunae to each other and the central canal

Question 25

What are canaliculi formed from

Answer 25

osteocytes

Question 26

What is interstitial lamellae

Answer 26

old haversian systems found between osteons and fill the space

Question 27

What is the outer circumferential lamellae

Answer 27

lining on the outer surface of bone under periosteum

Question 28

What is the inner circumferential lamellae

Answer 28

lining on inner sruface of bone under the endosteum

Question 29

Where is immature bone found

Answer 29

skeleton of developing fetus, adult alveolar sockets, and tendon attachments

Question 30

What is immature bone composed of

Answer 30

nonlamellar bone composed of interlacing collagen fibers

Question 31

Describe the appearance of immature bone

Answer 31

more cell rich than mature bone cells randomly arranged

Question 32

What is the matrix of immature bone compared to mature bone

Answer 32

less mineralized with more ground substance than mature bone

Question 33

What does immature bone stain and why

Answer 33

basophilic due to more ground substance

Question 34

What type of bone will lack osteons

Answer 34

immature bone

Question 35

What is the periosteum

Answer 35

collagenous membrane on the outer surface of bone

Question 36

What does the periosteum contain

Answer 36

vessels, nerves, and nociceptors

Question 37

What are the two layers the periosteum is composed of

Answer 37

fibrous outer layer | inner osteogenic layer

Question 38

What composes the fibrous outer layer of the periosteum

Answer 38

Dense irregular CT

Question 39

What composes inner osteogenic layer of the periosteum

Answer 39

osteoprogenitor cells

Question 40

What does the endosteum cover

Answer 40

covers the marrow cavity

Question 41

What does the endosteum contain

Answer 41

osteoprogenitor cells

Question 42

What is the structure/appearance of osteoprogenitor cells

Answer 42

flattened cells that resemble fibroblasts

Question 43

What type of staining of the cytoplasm do osteoprogenitor cells stain

Answer 43

basophilic

Question 44

What is the location of osteoprogenitor cells

Answer 44

inner layer of periosteum endosteum lining haversian and volkmann's canals

Question 45

What will osteoprogenitor cells differentiate into

Answer 45

osteoblasts

Question 46

What is the function of osteoblasts

Answer 46

form chondroblasts, adipocytes, and fibroblasts appositional bone formation

Question 47

What do osteoblasts eventually become

Answer 47

osteocytes

Question 48

What do osteoblasts secrete

Answer 48

collagen and ground substance that forms the initial unmineralized bone

Question 49

What is the initial unmineralized bone called

Answer 49

osteoid

Question 50

What is an osteocyte

Answer 50

bone cell

Question 51

How are osteocytes formed

Answer 51

when an osteoblast becomes embedded in the matrix it has secreted

Question 52

Where are osteoblasts found

Answer 52

form a single cuboidal cell layer on the surface of the growing bone, sitting on a light band of osteoid

Question 53

What do osteoblast cytoplasm stain

Answer 53

basophilic due to rER

Question 54

How is the calcification process of bone initiated

Answer 54

osteoblasts secreting vesicles containing alkaline phosphatase

Question 55

What is the function of osteocytes

Answer 55

maintain the bone matrix

Question 56

The death of an osteocyte results in what

Answer 56

reabsorption of bone

Question 57

How do osteocytes communicate

Answer 57

via gap junction

Question 58

Where are the gap junctions in osteocytes

Answer 58

canaliculi connect lacunae in which the osteocytes sit

Question 59

What are the different types of osteocytes

Answer 59

Inactive (quiescent) Formative Resorptive

Question 60

What type of organelles does an inactive osteocyte have

Answer 60

few organelles

Question 61

What type of organelles does a formative osteocyte have

Answer 61

rER

Question 62

What type of organelles does a resorptive osteocyte have

Answer 62

lysosomes

Question 63

What is the structure of osteoclasts

Answer 63

large multinucleated acidophilic cells, nuclei sitting on the side of the cells further away from the bony trabecula

Question 64

Where in the bone can you find osteoclasts

Answer 64

sitting on the ruffled border, contacting the bone

Question 65

What is the function of osteoclassts

Answer 65

resorb bone matrix, releasing minerals back into the blood

Question 66

What do osteoclasts release to aid in their function

Answer 66

lysosomal hydrolases and organic acids that digest organic components and decalcify the underlying bone

Question 67

What is the name for where osteoclasts are found

Answer 67

Howship's lacunae: resorption bay

Question 68

What disease can result in increased osteoclast activity

Answer 68

hyperparathyroidism

Question 69

How does hyperparathyroidism result in increases osteoclast activity

Answer 69

increases PTH increases osteoclast activity

Question 70

What decreases osteoclast activity

Answer 70

calcitonin

Question 71

What occurs during intramembraneous ossificiation

Answer 71

Mesenchymal cells aggregate--turn into osteoblasts and secrete osteoid Osteoid will minerlize and osteoblasts will be surrounded by lacunae and become osteocytes

Question 72

Is cartilage involved in intramembraneous ossification

Answer 72

nope

Question 73

Where does intramembranous ossification occur

Answer 73

embryo skull bone and in fractures where the broken ends are very closely aligned

Question 74

What is the process of endochondral ossification

Answer 74

Hyaline cartilage models of bone perichondrium forms a bony collar around the cartilage model (appositional growth)--> periosteum Primary ossification center develops Capillary roots break into the bone carrying osteoprogenitor cells that settle on the surface of the remaining calcified cartilage trabecules and turn into osteoblasts Osteoblasts build up the bone secondary ossification centers: capillary loops break into the epiphysis remaining epiphyseal plate forms bone towards the opposite directions lengthening the bone

Question 75

What are primary ossification centers

Answer 75

chondrocytes in the middle of the model become hypertrophic, secrete alkaline phosphatase, and the surrounding matrix undergoes calcification calcified matrix inhibits diffusion of nutriets--death of the suicidal cells death of chondrocytes the matrix breaks down forming a cavity

Question 76

When does bone via endochondral ossification untimately calcify

Answer 76

age in the 20s

Question 77

What is the epiphyseal plate

Answer 77

flat plate of hyaline cartilage seen in young, growing bone

Question 78

What are the layers of endochondral ossification

Answer 78

1. Zone of reserve cartilage 2. zone of proliferation 3. zone of hypertrophy 4. zone of calcified cartilage 5. zone or resportion

Question 79

What is the zone of proliferation look like

Answer 79

cartilage cells are arranged into rows

Question 80

What type of growth will increase diameter of bone

Answer 80

appositional growth

Question 81

Where does appositional growth occur

Answer 81

periosteum