Bone structure and function

Question 1

What is the function of bone

Answer 1

structural function, mobility and strength, support, protection for the body- skull protects brain, storehouse essential material- production and storing of minerals such as calcium, fat production and storage

Question 2

Typical long bones- epiphysis

Answer 2

distal and proximal. These are covered with cartilage, and it is made up of spongy

Question 3

Typical long bones- shaft/ diaphysis

Answer 3

this is covered with cpm[act bone, it has medullary cavity, inside this it has a endosteum and connective tissue, bone marrow and blood vessel

Question 4

Typical long bones- metaphysis

Answer 4

the metaphysis attaches the diaphysis to the epiphysis

Question 5

Typical long bones- periosteum

Answer 5

all the way around it is a periosteum- outer layer is were tendons and ligaments attach too, the inside has osteoprogenitor cells

Question 6

Typical long bones- what is all away round long bones

Answer 6

a layer of compact cortical bone to make it strong

Question 7

types of osseous tissue- compact

Answer 7

80% total mass, solid hard layer, external layer of all bones- strength down long axis, not strong down transverse or lateral impacts

Question 8

types of osseous tissue- spongy

Answer 8

20%- honeycomb network, found in inner parts of axial skeleton and epiphyses of long bone, good shock absorber/ good at redisturbuting pressures and stressors

Question 9

Compact (cortical) bone- structure

Answer 9

denser the spongy bone/ trabecular bone, but less flexible

Question 10

Compact (cortical) bone- osteon

Answer 10

connective rings (lamellae) of calcified matrix surrounding vertically oriented blood vessel

Question 11

Compact (cortical) bone- make up

Answer 11

made with artery and vein running down the middle, osteoblasts lay down collagen fibres in a criss- cross fashion- helps with strength, this leads to a ring of bone around the blood vessel

Question 12

Compact (cortical) bone- rings

Answer 12

end up with lots of rings going in a spiral, this forms osteons, lots of these lay next to each other on the long axis of the diaphysis- means it can withstand great pressure down vertical axis, between each osteon is more lamelle

Question 13

Compact (cortical) bone- what separates the lamellae

Answer 13

separating the lamellae is the lucunai , this is a pit/ lake, inside there is extracellular fluid and osteocytes (bone cells)

Question 14

Compact (cortical) bone- osteocytes

Answer 14

osteocyte are mature bone cells, osteoblasts become trapped within itself and turns into an osteocyte

Question 15

why are osteocytes important

Answer 15

they are important because they provide information about how much building/ breaking down needs to be done. Osteocytes form projection (canaliculi), branch out and receive information from other osteocytes in other lucane. they have a role in regulation nutrients

Question 16

Spongy (trabecular/ cancellous) bone- structure

Answer 16

lattice like, light- less compact, collagen fibres laid down by osteocytes, laid down along lines of stress and this forms trabeculae

Question 17

Spongy (trabecular/ cancellous) bone- lines of stress

Answer 17

well organised along lines of stress- gives strength and resisting stress and force without breaking- forces from different angle. It dissipates stress- lots of projection of bones to transfer stress through, bone marrow forms holes, within these holes- blood vessels and extracellular fluid

Question 18

Spongy (trabecular/ cancellous) bone- osteocytes and nutrients

Answer 18

osteocytes in lacunae on the surface of trabeculae, nutrients directly from the blood in the medullary cavities

Question 19

Cell types in bones- osteogenic/ osteoprogenitor cells

Answer 19

undifferentiated cells- sit and wait to receive information to be stimulated to make new bone- when stimulated they are able to divide into osteoblast. Found in endosteum and inner layer of periosteum.

Question 20

Cell types in bones- Osteoblasts

Answer 20

build matrix and collagen fibres but cannot divide, they build bone and get trapped within their own system of bone. when they have built their surroundings, they are referred to as osteocytes.

Question 21

Cell types in bones- osteocytes

Answer 21

mature cells, sit in lacunae. These maintain bone tissue and what we need through communication about nutrients needed (long branches)

Question 22

Cell types in bones- osteoclasts

Answer 22

clear bone cells, bigger than other cells, forms monocytes- good at clearing up debris. Function is reabsorption, the destruction of bone matrix.

Question 23

What does the border of the osteoclasts allow

Answer 23

the rough border allows them to stick to surface of bone and release enzymes and acids that destroy bone, during the process they clear up and absorb debrie- able to release minerals back into blood system. they only do this based on what osteocytes signals are needed

Question 24

what is remodelling of bone

Answer 24

absorption is an ongoing process for bones to keep them healthy- continually make new bone and break down old bone- called remodeling.

Question 25

what is coupling (remodelling)

Answer 25

equilibrium between amount absorbed and amount broke down need stop be at right rate and each cell is doing the right amount- this is called coupling. if something goes wrong (net bone change), this system is called uncoupling

Question 26

Ageing of osteoblasts and osteoclasts

Answer 26

osteoblasts age quicker than osteoclasts- more building less clearing at older age

Question 27

Location of cells- osteocytes

Answer 27

found in lacunae of compact of spongy bone

Question 28

Location of cells- osteoblasts

Answer 28

found on surface of bone

Question 29

Location of cells- osteoprogenitor cells

Answer 29

found in endosteum and inner layers of periosteum

Question 30

Location of cells- osteoclasts

Answer 30

found on surface of bone

Question 31

process of modelling and remodelling

Answer 31

bones are continually modelling through childhood and adolescence, much of the cellular activity in a bone consist of removal and replacement at the same sit, this process is remodelling. Many things can interfere with the developments of strong and healthy skeleton, e.g. osteoporosis

Question 32

how do bones get longer

Answer 32

new cartilage gets produced on the epiphyseal side on the plate , old cartilage calcified- turns into bone, cartilage grows, cartilage replaced by bone

Question 33

how does bone stop growing in length

Answer 33

after a certain age epiphyseal plate stops producing cartilage and collagen, meaning the amount of bone being produced to lengthen stops, from 18-25

Question 34

how do bones get wider

Answer 34

this is called appositional growth, the presents of the blood vessels within the bone stimulate the osteoblasts to make more bone. this makes bones wider.

Question 35

what grows quicker length or width

Answer 35

the length and width need to grow at the same time (coupling), if length grows quicker than width then a think weak bone occur

Question 36

What can go wrong with bone growing- osteoporosis

Answer 36

low bone density (low peak bone mass)- osteoporosis. Bones are weaker and are more likely to break

Question 37

What can go wrong with bone growing- osteogenesis imperfecta

Answer 37

genetic disorder- don’t produce enough collagen= bones are weaker, and brittle. Doesn’t grow as quickly as it should, epithelial plates may be damaged

Question 38

What can go wrong with bone growing- Paget’s disease of bone

Answer 38

bones replaced faster than usual (problem with bone regeneration), the bone isn’t made that well- meaning it i weaker

Question 39

What can go wrong with bone growing- cancer

Answer 39

bone cancer

Question 40

What can go wrong with bone growing- bone infection

Answer 40

usually after some form of trauma or surgery expose to bone

Question 41

blood supply to bones- periosteal arteries

Answer 41

periosteum and outer osteons of compact bone- breaks through volkmann canals. Supplies blood to osteons and outer parts of bone

Question 42

blood supply to bones- why do bones need good blood supply

Answer 42

large blood supply because of activity going on there. Constant remodelling and coupling- blood is supplied by many different areas. bone are important for overall health, therefore, the bones are able to communicate with the whole body.

Question 43

blood supply to bones- nutrient arteries

Answer 43

medially cavity and osteons of inner compact bone, enters through diaphysis through the nutrient foramen

Question 44

blood supply to bones- metaphyseal arteries

Answer 44

spongy bone and marrow in this rea, enter the metaphysis and they supply trabecular/ spongy bone

Question 45

blood supply to bones- epiphyseal arteries

Answer 45

enter through epiphyseal, supplies spongy bone and marrow in this area

Question 46

blood supply to bones- internal bleeding

Answer 46

when bones are broken, and fractures can lead to internal bleeding and damage of arteries. Bones can take longer to heal if damage to arteries occur, and can lead to parts of the bone dying. Femur is susceptible to this. Interruption to blood supply can take a while to fix

Question 47

What is remodelling affected by

Answer 47

age- some cells slow down, mechanical stress, genetic and environment, calcium and phosphate levels- nutrition, hormones

Question 48

effect of age on bones- Demineralisation

Answer 48

demineralisation from the age of 40 years- osteopenia. Reduces 1% per year. Worse in women- 40-45 years- hormone oestrogen and production is slower

Question 49

effect of age on bones- osteoporosis prevention

Answer 49

HRT- hormone replace therapy to prevent osteoporosis

Question 50

Why are weight bearing exercises important

Answer 50

Weight bearing exercise is important for developing and healing- to a certain degree. Relevant to weight bearing status of patient. Lack of weight bearing activity builds bones.

Question 51

effect of lack of mechanical stress

Answer 51

lack of mechanical stress reduces bone density- if in cast for 12 weeks will half its normal levels. With activity bone density can be built up but can take up to 4 months before seeing good results. Elderly may never get back to full bone density- due to age related issues

Question 52

effect on bone density- genetic and environmental

Answer 52

black people have greater bone density- asians have weakest bones
environment- it is important for children to have a good balance diet and get lots of exercise

Question 53

effect on bone density- nutritional

Answer 53

calcium and phosphate- if there is a lack of calcium bones will be broken down due to signalling by the osteoblasts. Calcium is important in many stems in body such as blood clotting

Question 54

effect on bone density- hormones

Answer 54

growth hormones and sex hormones, parthod hormones, calcitonin hormones