skeleton and bones

Question 1

what does the skeleton consist of?

Answer 1

bones, joints and cartilage which acts as a supportive framework

Question 2

what does appendicular skeleton consist of?

Answer 2

limbs and girdles

Question 3

what does axial skeleton consist of?

Answer 3

long axis i.e. vertebral column, skull, ribcage

Question 4

what are the functions of the skeleton ? (7)

Answer 4

• maintains posture
• acts as framework for muscle and tissue attachment
• allows movement as whole/ isolation as levers created
• bones protect organs and reduce injury e.g. ribs
• blood cell production
• storage of minerals e.g. calcium
• endocrine functions

Question 5

what do bones provide?

Answer 5

resting ground for muscles and protection of vital organs

Question 6

what are long bones? give an example

Answer 6

support bodyweight as they are longer> wide; help facilitate movement e.g. femur

Question 7

what are short bones? give an example

Answer 7

cube- shaped bones that provide stability and allow flexibility e.g. wrist

Question 8

what are flat bones? give an example

Answer 8

thin, flat and slightly curved to provide protection and large surface area for muscle attachment e.g. sternum, skull

Question 9

what are irregular bones? give an example

Answer 9

complicated shapes to protect certain organs e.g. pelvis, hips

Question 10

what are sesamoid bones? give an example

Answer 10

embedded in tendons to protect from stress e.g. hands, knees

Question 11

how many bones in adult body?

Answer 11

206

Question 12

what is spongy bone?

Answer 12

act as inner layer as arranged into trabecular so resist decompressing forces without deforming

Question 13

where is spongy bone found?

Answer 13

epiphysis end

Question 14

what does spongy bones contain?

Answer 14

• spaces in-between contain red bone marrow so can produce blood cells
• blood vessels within deliver nutrients to osteons and remove waste

Question 15

what is compact bone?

Answer 15

more dense and solid on outer layer to protect and withstand muscle pull

Question 16

where is compact bone and what percentage does it make up of mass?

Answer 16

• 80%
• found in diaphysis shaft

Question 17

what is an osteoblast?

Answer 17

cell in body that builds new bone tissue

Question 18

where are osteoblasts found and what do they secrete?

Answer 18

• found in growing portions of bone e.g. endosteum
• secrete collagen matrix and other proteins

Question 19

what is an osteoclast ?

Answer 19

cell that nibbles at and breaks down bone; responsible for bone resorption

Question 20

how do osteoclasts dissolve old bones?

Answer 20

release enzymes that trigger chemical reactions

Question 21

what develops from osteoblast? where is it found?

Answer 21

osteocyte which is found in a small chamber called a lacuna ; lies within substance of fully formed bone

Question 22

what do osteoblasts secrete? and its significance

Answer 22

osteoid which calcifies within a few days and entraps osteoblasts

Question 23

what is osseous tissue?

Answer 23

strong connective tissue made from collagen and hard minerals e.g. calcium

Question 24

what does bone matrix consist of?

Answer 24

intercellular substance consists of collagen fibres, ground substance and inorganic bone salts

Question 25

what are the properties of osseous tissue?

Answer 25

very hard due to calcium salts, light weight and able to resist tension

Question 26

what is the purpose of collagen in osseous tissue?

Answer 26

acts as framework for building calcium rich inorganic matrix

Question 27

what is a osteon?

Answer 27

structural unit of compact bone that consists of concentric bone layers called lamella

Question 28

what do lamellae in osteons surround?

Answer 28

long passageway called haversian canal

Question 29

what is the structure of osteons- how are they aligned?

Answer 29

- run longitudinal axis of bone - hollow inside - made of central canal surrounded by expanding rings - aligned same way as force applied

Question 30

how are osteocytes connected?

Answer 30

cavities interconnected by canaliculi

Question 31

what does central canal contain?

Answer 31

nerves, lymphatics and blood vessels

Question 32

where is the epiphysis? describe

Answer 32

end of bone which is wide and filled with spongy bones

Question 33

what is epiphysis covered in and why?

Answer 33

articular cartilage so bones can slide pass without friction

Question 34

what is the metaphysis?

Answer 34

growth zone between the epiphysis and diaphysis during development of long bone

Question 35

what is the diaphysis?

Answer 35

hollow, tubular shaft of long bone

Question 36

what is the central cavity of diaphysis?

Answer 36

medullary cavity yellow bone marrow is stored

Question 37

where does growth take place?

Answer 37

epiphyseal plate

Question 38

what happens when the plate is ossified?

Answer 38

becomes an epiphyseal line

Question 39

what does yellow bone marrow store?

Answer 39

fat

Question 40

what does red bone marrow store?

Answer 40

blood

Question 41

what is the endosteum?

Answer 41

membranous lining of hollow cavity of bone

Question 42

what is the periosteum?

Answer 42

apart of the outer double layered structure that acts as a tough protective layer

Question 43

what part doesn't the periosteum cover and why ?

Answer 43

where epiphysis meets other bones to form joints as they are covered with articular cartilage

Question 44

what does periosteum contain?

Answer 44

blood vessels, nerves and lymphatic vessels that nourish compact bone

Question 45

what attach to bones at periosteum?

Answer 45

tendons and ligaments

Question 46

how do long bones come about?

Answer 46

endochondral ossification

Question 47

what is endochondral ossification?

Answer 47

process by which growing cartilage is systematically replaced by bone to form the growing skeleton

Question 48

what is remodelling?

Answer 48

process of undergoing structural reorganisation, alteration or renewal of living tissue

Question 49

describe bone remodelling

Answer 49

continuous metabolic process of bone breakdown by specialised cells called osteoclasts followed by formation of new bone tissue by osteoblasts

Question 50

how much bone is replaced each year? what does it depend on?

Answer 50

10% depending on amount of stress

Question 51

what is wolff's law?

Answer 51

describes idea that bone density changes in response to force placed on bone

Question 52

when does bone ossification begin ?

Answer 52

8th week of gestation until 25 years olds

Question 53

what is the name of the process of epiphyseal plates increasing in thickness?

Answer 53

appositional growth

Question 54

what is it called when meschehymal tissue is directly converted to bone?

Answer 54

intramembranous ossification

Question 55

how does ossification begin?

Answer 55

mesenchymal cells differentiate into chondrocytes and form cartilage model for bones

Question 56

what is formed around hyaline cartilage model?

Answer 56

bone collar

Question 57

what happens to the hyaline cartilage?

Answer 57

it undergoes cavitation so empty space is formed

Question 58

what invades after cavitation?

Answer 58

internal cavities by periosteal bud and spongy bone formation

Question 59

what is formed as ossification continues?

Answer 59

medullary cavity

Question 60

what appears in preparation for the last step of ossification?

Answer 60

secondary ossification centres in epiphyses

Question 61

what happens in the last stage?

Answer 61

ossification of epiphyses ; hyaline cartilage remains only in epiphyseal plates