Histology of Bone

Question 1

what cells do bone originate from?

Answer 1

mesenchyme stem cells

Question 2

What are osteoblasts?

Answer 2

bone generating cells

Question 3

What are the gaps called between the bone of a babies skull before they are sutures?

Answer 3

fontanel

Question 4

What is intramembranous ossification?

Answer 4

Bone development then occurs within the mesenchyme from these cells (mainly osteoblasts)

between different bone

Question 5

What is endochondral ossification?

Answer 5

Bone development then occurs within the mesenchyme from these cells (mainly osteoblasts)

within the bone

Question 6

What is immature bone called? (not mineralsied)

Answer 6

osteoid bone

Question 7

What are the 3 names for immature bone?

Answer 7

IMMATURE
WOVEN
OSTEOID

Question 8

What inogranic salts mineralise the immature bone to mature bone?

Answer 8

calcium hydroxyapatite crystals - mineralised, rigid, hard

Question 9

Where do osteoclasts come from?

Answer 9

blood stream

Question 10

What is the matrix of bone occupied by?

Answer 10

Matrix occupied by collagen fibres and specialized bone cells – osteoblasts, osteocytes and osteoclasts.

Question 11

What is cortical bone?

Answer 11

dense and solid and surrounds the marrow space

Question 12

Is this compact or spongy bone?

Answer 12

compact

Question 13

What is lamellae?

Answer 13

concentric layer of bone

Question 14

Is this compact or spongy bone?

Answer 14

spongy

Question 15

What is the central canal of an osteon called?

Answer 15

Haversian canal

Question 16

What is an Haversian system also known as?

Answer 16

osteon

Question 17

What is at the central canal of an osteon?

Answer 17

blood vessels

Question 18

What are other names for spongy bone?

Answer 18

trabecular
cancellous

Question 19

What do you find in the marrow cavity of bone?

Answer 19

formation of blood - Hematopoiesis
fat (adipose tissue)

Question 20

Where are osteocytes found in compact bone?

Answer 20

lacunae (trapped)

Question 21

What factors can change the composition of bone?

Answer 21

age and metabolic status

Question 22

Is bone a dynamic tissue?

Answer 22

yes, Composition changes with age and metabolic status

Question 23

In adults, when would pre-mineralised/immature bone be found?

Answer 23

Organic component (pre-mineralised/immature bone) is called osteoid/woven bone. In adults only found where bone remodelling is occurring

Question 24

What are the components of the ECM of bone?

Answer 24

60-70% inorganic salts, 30-40% collagen and remainder (@5%) is protein and carbohydrate

Question 25

What collagen fibre dominates in collagen?

Answer 25

type I

Question 26

What do the gaps between collagen i the ECM provide?

Answer 26

Gaps’ provide space for bone salt crystals (up to 50% of calcium hydroxyapatite crystals within fibres)

Question 27

What glycoproteins are associated with the ECM of bone?

Answer 27

osteonectin

Question 28

what is the role of osteonectin in bone?

Answer 28

Glycoproteins associated with matrix include osteonectin which acts as an adhesive between the collagen, hydroxyapatite crystals and cells

Question 29

What synthesises collagen?

Answer 29

osteoblasts

Question 30

How do collagen fibres increase the strength of bone?

Answer 30

Collagen fibres have differing orientations within bone to enhance strength

Question 31

What do Sharpey's fibres connect?

Answer 31

Sharpey’s fibres connect periosteum (P) to cortical bone. Tendons and ligaments also insert into bone by means of collagen fibres

Question 32

What is the precursor of osteoblasts?

Answer 32

osteoprojenitor cells

Question 33

What do osteoblasts release to initiate mineralisation of the bone?

Answer 33

release of vesicles rich in alkaline phosphatase and make calcium hydroxyapatite

Question 34

What do osteoblasts become when surrounded by mineralised bone?

Answer 34

osteocytes

Question 35

What is a canaliculi?

Answer 35

a minute canal in a bodily structure: as. a. : one of the hairlike channels ramifying a Haversian system in bone and linking the lacunae with one another and with the Haversian canal. connect lacunae to each other and central canal

Question 36

Name structures A and B

Answer 36

A = canaliculi B = lacuna

Question 37

What cells are shown here?

Answer 37

osteoclats next to resorption bone

Question 38

What cell is multi-nucleated?

Answer 38

osteoclasts

Question 39

What is the role of osteoclasts?

Answer 39

Found on the surface of the bone undergoing resorption/ remodelling

Question 40

What cell is involved in calcium homeostasis?

Answer 40

osteoclasts parathyroid hormone stimulates, calcitonin depresses their activity

Question 41

What is shown here?

Answer 41

resorption pit/bay showing osteoclasts also

Question 42

What is the resorption pit also called?

Answer 42

Howship's lacuna

Question 44

Where is a ruffled border found?

Answer 44

In EM numerous folds seen in the cytoplasm of the osteoclast – “ruffled border” at the surface of resorption bay/pit (Howship’s lacuna)

Question 45

What is found in the cytoplasm of the osteoclasts?

Answer 45

Cytoplasm of cell contain numerous mitochondria, Golgi and lysosomes (=active cells) associated with resorption and degradation of bone

Question 46

How would you describe the bone of the alveolar bone?

Answer 46

modified compact bone

Question 47

What is the difference between the alveolar bone and compact bone?

Answer 47

Is similar to compact bone but has many perforating collagen fibres (Sharpey’s fibres)

Question 48

What bone surrounds the alveolar bone?

Answer 48

normal compact bone and spongy bone

Question 49

Name the bone types at the red, blue and yellow arrows

Answer 49

red = modified compact bone blue = normal compact bone yellow = spongy bone

Question 50

What type of bone is shown here?

Answer 50

spongy bone

Question 51

What does anastonise mean?

Answer 51

the meeting of 'mouths' / connecting

Question 52

What bone diseases shown here?

Answer 52

osteoporosis

Question 53

How are the lamallae arranged within the trabeculum?

Answer 53

parallel to one another

Question 54

What can cause the different orientations of trabeculae?

Answer 54

Different orientations of trabeculae occur in response to stress requirements