bones

Question 1

how long does it take for all bone in the body to be replaced

Answer 1

10 years

Question 2

what part of the body do bones NOT protect

Answer 2

the gut

Question 3

what is haematopoiesis

Answer 3

the process of blood cell formation in bone marrow

Question 4

what are the 2 main components of bone

Answer 4

collagen (gives the bone tensile strength
calcium phosphate crystals (mineral) to harden the bone and give it compressional strength

Question 5

what is cartilage

Answer 5

similar to bone but no calcified

Question 6

3 things bone is made from

Answer 6

osteoblasts, osteocytes and osteoclasts

Question 7

what is bone supplied by

Answer 7

blood vessels and nerves

Question 8

what is the head of a long bone called

Answer 8

epiphysis (head) spongy bone, covered by hyaline cartilage

Question 9

what is the shaft of a long bone called

Answer 9

diaphysis- hollow cylinder which contains bone marrow in marrow cavity

Question 10

what is the periosteum

Answer 10

fibrous connective tissue sheath covering external surfaces.
contains fibroblasts, mesenchymal cells and osteoclasts

Question 11

fibroblast

Answer 11

in the periosteum of long bone that can synthesize collagen

Question 12

what can mesenchymal cells differentiate into

Answer 12

osteoblasts and chondroblasts

Question 13

2 different kinds of bone

Answer 13

trabecular/ cancellous (spongy- in areas of stress)
cortical (solid- stiffness and strength)

Question 14

how are trabecular bones good for areas of stress

Answer 14

high surface area for metabolism
goes horizontal and vertical for more strength

Question 15

haversian canal

Answer 15

carry blood along the axis of the bone in cancellous bones

Question 16

volkmans canal

Answer 16

carries blood perpendicularly across the bone in cancellous bones

Question 17

what is cortical bone

Answer 17

arranged in concentric circles (onion).
each layer contains collagen fibres which are flexible and orientated differently

Question 18

haversian canals

Answer 18

carry blood along cortical bones

Question 19

what is the organic matrix composed of

Answer 19

mostly protein fibres but also crystalllised mineral salts and water

Question 20

what is rickets

Answer 20

Vit D deficiency, failure of Ca2+ absorption

Question 21

what is scurvy

Answer 21

Vit C deficiency- lack of collagen

Question 22

osteoblast

Answer 22

bone forming cell, covering surface of bone
when stimulated to form bone it will deposit collagen and hydroxyapatite

Question 23

osteoclast

Answer 23

form seal on bone, reabsorb bone matrix by demineralization if there is mechanical stress or physiological demands
suck on bone and dissolve structure

Question 24

osteocyte

Answer 24

mature bone cell. maintain bone matrix by cell to cell communication (finger like structures

Question 25

osteoprogenitor cells

Answer 25

stem cell population

Question 26

hypertrophy

Answer 26

less bone formation than bone reabsorption so osteoclasts are more active

Question 27

atrophy

Answer 27

more bone formation that bone reabsorption so osteoblasts are more active

Question 28

4 steps of bone remodelling cycle

Answer 28

1. osteoprogenators differentiate into osteoblasts 2. osteoblasts lay down new bone 3. cells become deactive 4. reabsorption by osteoclasts

Question 29

wolff's law

Answer 29

bone adapts to the load under which it is placed, 'use it or lose it' (ex. astronauts)

Question 30

what is ossification

Answer 30

when the original cartilage is coverted into bone in the fetus

Question 31

what is the epiphyseal plate

Answer 31

plate of cartilage in between the head (epiphysis) and the shaft (diaphysis) of the long bone to allow the bone to grow. this gets smaller until the bone is at full length and it dissapears