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Flashcards in Bones 1 Deck (38)
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1

What are the functions of bones?

Structural

Hearing

Protection (of soft tissue and internal organs)

Standing/support

Mineral storage - main reservoir for calcium and phosphorus

Movement: - Transmit force of muscular contraction, attachment site for muscles

Metabolic - 

-Haematopoiesis, blood cell production In bone marrow

-Homeostasis of ionised calcium (Ca2+) in blood

-Defence against acidosis

2

What are the different classes of bones?

Long

Short

Flat

Irregular

Sessamoid

3

What is the name given to the fibrocartilagenous layer that encloses bone?

Periosteum

4

Where is red bone marrow, what does it produce?

Metaphysis - production of red blood cells 

 

(metaphysis is the region between the epiphysis and the diaphysis)

5

What is the function of yellow bone marrow and where is it found?

Yellow bone marrow is found in the diaphysis - mainly contains fat cells

6

What percentage of skeletal mass is cortical bone and spongy bone?

Trabecular bone = 20% bone mass

Cortical bone = 80% skeletal mass

7

What type of bone development forms flat bones?

Intramembranous ossification

8

What is the process of intramembranous ossification?

Bone forms as a fibrous plate

Bone cells differentiate from fibroblasts and haematopoietic precursors

9

How do long bones form?

Endochondral ossification

10

What is the process of endochondral ossification?

Bone forms as cartilage (3 months)

Blood vessels invade cartilage

Osteogenic (bone forming) cells invade with blood vessels

Cartilage remains in growth plate

Growth plate fuses at age 21 in males and 18 in females

11

How is bone composition determined?

Method to determine composition:

–Bone cores from femoral heads weighed in air

–Dehydrated @ 105°C for 24 hours

•Weighed again

•Water content = wet – dry weight

–Ashed @ 600° C for 24 hours

•Weighed again

•Mineral content = ash weight

•Organic content = dry weight – ash weight

12

Example of subchondral femoral head bone composition

13

What material does bone consist of?

•Hydroxyapatite: Ca10(PO4)6(OH)2

14

What quality does mineral add to bone?

Rigidity

15

How does the mineralisation of bone change with time?

•Recently deposited bone has less mineral

–dark gray

–nearer the surface

 

•Older bone is more mineralized

–light grey/white

–further from surface

16

What type of collagen is found in bone?

Type 1

17

What is the structure of collagen type1?

Triple helix protein

Heterotrimer (two a1 chains and one a2 chain)

They combine to make fibrils

Fibrils combine to make fibers

Incorporate bone mineral

18

look

19

What type of water exists in bones?

Pore water (pores within bone e.g haversian canals)

Bound water (loosely or tightly bound, works well with collagen to provide elasticity)

 

20

How does the water content in our bones change as we age?

The amount of bound water decreases

The amount of pore water increases

21

Which portion of bone sunstance is respoonsible for elasticity?

Organic 

22

How is the composition of bone investigated?

Spectroscopy

23

What type of cells are osteoclasts?

– Multinucleated cells formed by the fusion of mononuclear precursors; responsible for degradation of bone

24

WHat is the role of osteoblasts?

Responsible for the synthesis of new bone

25

What are osteocytes?

Osteoblasts that have become embedded within bone, function as sensors of mechanical load

26

How long does it take osteoid to calcify?

About 10 days

27

What organelles are prevalent in osteoblasts?

Endoplasmic reticulum and golgi apparaturs, due to their biosynthetic function

28

How may nuclei are typically found in osteoclasts?

5

29

Where are osteoclasts found?

In pits on the bone surface called resportion bays

30

What gives the osteoclasts cytoplasms' foamy appearance?

High concentration of vesicles and vacuoles