Bones and Bone Growth

Question 1

Function of cartilage and bone

Answer 1

1-protect vital structures
2-movement
3-storage of minerals

Question 2

What minerals are stored in bone?

Answer 2

Ca++

Question 3

Calcitonin

Answer 3

hormone that inhibits activity of osteoclasts and reduces Ca++ levels in the blood

Question 4

Parathormone or parathyroid hormone

Answer 4

increases the activity of osteoclasts and releases Ca++ into the blood

Question 5

chondrocytes

Answer 5

secrete extracellular matrix (cartilage), they are then embedded in the matrix

Question 6

what is the extracellular matrix made of? (cartilage)

Answer 6

chondroitin sulphate (clear gelatinous protein) plus collagen, elastic fibres and other proteins

Question 7

Hyaline cartilage

Answer 7

cushions articular surfaces (synovial joints)

Question 8

define ossification and state when does it occurs

Answer 8

process through which hyaline cartilage is gradually and almost entirely replaces by bone. Before birth into early adulthood.

Question 9

Where do you find hyaline cartilage?

Answer 9

larynx, trachea, bronchi, costal cartilage

Question 10

elastic cartilage, properties and where

Answer 10

Never ossifies, found in ears, tip of nose and epiglottis!!

Question 11

Fibrocartilage

Answer 11

formsthe tough shock absorbing discs between symphyses in midline of the body (intervertebral discs)

Question 12

What is in the bone matrix

Answer 12

calciumhydroxoapatite bound to osteoid

Question 13

which cells synthesise the bone matrix?

Answer 13

osteoblasts`

Question 14

osteopogenitor cells

Answer 14

give rise to oosteoblasts in bone growth and repair

Question 15

osteoblasts

Answer 15

secrete bone matrix (they have abundant rough ER, Golgi) and eventually become osteocytes

Question 16

osteocytes

Answer 16

mantain bone matrix. Buried alive in spaces in bone matrix (lacunae) in compact bone

Question 17

how are osteocytes connected to one another?

Answer 17

by cytoplasmic processes lying in narrow channels (caniculi)

Question 18

osteoclasts

Answer 18

derived from clood monocytes.

reabsorb bone as they drill through matrix (epiphyses during growth, at remodelling sites)

Question 19

fibroblasts

Answer 19

produce collagen and other fibres

Question 20

compact bone

Answer 20

strong, light cylinder.

resists compressive forces

Question 21

formula of calcium hydroxyapatite

Answer 21

(Ca5 (PO4)OH))

Question 22

medullary cavity

Answer 22

supported by cancellous bone

Question 23

what happens in red bone marrow?

Answer 23

haematopoiesis

Question 24

what is haematopoiesis and where does it occur?

Answer 24

red blood cell formation, in red bone marrow

Question 25

what is the epiphysis

Answer 25

end of a bone that has an articular surface

Question 26

what is the end of an articular bone called?

Answer 26

Epiphysis

Question 27

what happens while the epiphyseal plate is active?

Answer 27

cartilage is divided and then removed by osteoclasts. Osteoblasts then invade the space and lay done new bone. Bone is growing.

Question 28

what happens with the production of sex steroids?

Answer 28

epiphyseal plate closes and cartilage plate is replaced by bone (synostosis).

Question 29

Periosteum

Answer 29

• made of osteoblasts, osteoclasts and fibroblasts
• has a rich nerve and blood suppply
• covers whole bone apart from articular surfaces`

Question 30

what triggers hypertrophy?

Answer 30

physical stress

traction and pressure (muscles attached and pulling on bone)

Question 31

trabeculae

Answer 31

cancellous bone “lines”laid down along the lines of stress

Question 32

atrophy occurs when

Answer 32

lack of weight bearing
menopause (lasck of oestrogen)
lack of vitamin D

Question 33

Primary ossification centre

Answer 33

starts in the centre of diaphysis of long bone

Question 34

secondary ossification centre

Answer 34

in the epiphysis, eventually only cartilage is plate between diaphysis and epiphysis

Question 35

4 zones in epiphysis

Answer 35

resting-epiphyseal (reserve cells)
growth-mitosis occurs (proliferation)
maturation-cells tranforming, enlarging and matrix calcifies
osteogenic- cartilage removed by osteoclasts, osteoblasts replace it with bone