201 L7

Question 1

Name the types of bone cells.

Answer 1

Osteoprogenitor cells
Osteoblasts
Osteocytes
Osteoclasts

Question 2

What is the bone ECM mainly composed of?

Answer 2

Type 1 collagen fibres
Hydroxyapatite
low levels of proteoglycans

Question 3

What are the types of adult bone?

Answer 3

Compact bone

Trabecular bone

Question 4

——— bone is organsied in ——— lamellae around ——- — forming ———-.

——– fibres are arranged in a —- —- fashion in each —– providing strength and —– to ———–.

Answer 4

Compact bone is organsied in concentric lamellae around blood vessels forming osteons.

collagen fibres are arranged in a criss cross fashion in each osteon providing strength and resistance to tension.

Question 5

——— bone have ——- lamellae that align in a particular way according to ———- that are put on it.

The bone remodels over time.

Answer 5

Trabecular bone have parallel lamellae that align in a particular way according to stresses that are put on it.

The bone remodels over time.

Question 6

Compact and trabecular bone have the same ————- organisation but different ———— organisation

Answer 6

Compact and trabecular bone have the same microscopical organisation but different macroscopical organisation

Question 7

In compact bone the ——- of each osteon within bone are —— and aligned ——– to the long axis of bone.

Answer 7

In compact bone the lamellae of each osteon within bone are cylindrical and aligned -parallel to the long axis of bone.

Question 8

What force do collagen fibres and the calcified ECM withstand?

Answer 8

Collagen = tension
ECM = compression

Question 9

Compact bone is found in regions of —- loads.

Spongy bone is found in regions of —– loads

Answer 9

Compact bone is found in regions of high loads.

Spongy bone is found in regions of low loads

Question 10

What forces does compact bone withstand?

Answer 10

Compression

Tension

Question 11

What forces does trabecular bone withstand?

Answer 11

Tension
Compression

In equal amounts

Question 12

What bone type provides the biggest strength?

Answer 12

Compact bone

Question 13

What is the composition of humans bone?

Answer 13

Water 25-30%
Mineral 60-70% - compression
Protein (collagen) 5%-15% - tension

Question 14

Describe Wolff’s law

Answer 14

Bone adapts to the loads under which it is placed.

The more you load the bone the stronger it gets (vice versa)

Question 15

Bone is highly adaptive

Bone is anisotropic: the ———– properties of bone are different when —— is applied in different ———–.

e.g The ——– strength of the bone is greater if loaded in the longitudinal axis than perpendicular to the longitudinal axis. Therefore cortical bone is —— in tension and ——- in compression.

Bone is viscoelastic: the ————- properties are different when ——— are applied at different ——–. More energy can be absorbed by bone at ——- loading rates. Therefore, the more strenuous the activity, the ——— the bone.

Answer 15

Bone is anisotropic (it’s not a homogenous equal loading): the mechanical properties of bone are different when load is applied in different directions. e.g the tensile strength of the bone is greater if loaded in the longitudinal axis than perpendicular to the longitudinal axis. Therefore cortical bone is weak in tension and tough in compression.

Bone is viscoelastic (an element of elasticity): the mechanical properties are different when loads are applied at different rates. More energy can be absorbed by bone at higher loading rates. Therefore, the more strenuous the activity, the stronger the bone.

Question 16

What is osteoporosis?

Answer 16

Bone resorption, osteoclast activity, is greater than bone formation, osteoblast activity, resulting in decreased bone mass.

Question 17

What are the effects of osteoporosis?

Answer 17

The density and quality of bone are reduced leading to weakness of the skeleton and increased risk of fracture.

Loss of mineral content

Question 18

Why are post-menopausal women at risk of developing osteoporosis?

Answer 18

Estrogen has a positive metabolic effect on bone so when this decreases there is an imbalance in osteoclast and osteoblast activity

Question 19

What are some risk factors of osteoporosis?

Answer 19

Aging
Sedentary lifestyle
Post-menopausal women
Smoking
Oral contraceptive
Low calcium diet
Thin build
Excessive alcohol and caffeine

Question 20

What are some treatments for osteoporosis?

Answer 20

High calcium diets

Bisphosphonates - anti-resorptive (slows down the osteoclast activity)

Exercise - loading the bones is good to stimulate the osteoblasts

Hormone replacement therapy - progesterone or estrogen

Question 21

What attaches muscle to bone?

Answer 21

Tendon

Question 22

Structure of ligaments and tendons:

Closely packed parallel bundles of ——– fibres,

Rows of ————,

——– network.

Some ——– fibres, more prominent in ————.

In some ligaments (e.g. ligamentum flava) —– fibres predominate.

Gliding and sliding of tendons is facilitated by tendon sheaths, an inner epitendineum
attached to the surface of the ———- and an outer parietal layer attached to surrounding
——–.
The intervening space is filled with synovial fluid rich in ——— ———.

Answer 22

Closely packed parallel bundles of collagen fibres,

Rows of fibroblasts,

Capillary network.

Some elastic fibres, more prominent in ligaments.

In some ligaments (e.g. ligamentum flava) elastic fibres predominate.

Gliding and sliding of tendons is facilitated by tendon sheaths, an inner epitendineum
attached to the surface of the tendon and an outer parietal layer attached to surrounding
tissue.
The intervening space is filled with synovial fluid rich in hyaluronic acid.

Question 23

If there is loss of —— in tendons and ligaments it leads to rapid ———–.

Answer 23

If there is loss of tension in tendons and ligaments it leads to rapid remodelling.

Question 24

What causes muscle wastage, bone thinning and loss of cartilage matrix?

Answer 24

Cause - Lack of loading stimuli

under use or immobilisation

Question 25

Long distance running causes site-specific reduction in ———— content in ——– cartilage which can lead to early onset of ———-.

Answer 25

long distance running causes site-specific reduction in proteoglycan content in articular cartilage which can lead to early onset of osteoarthritis

Excessive use

Question 26

Why do we need tissue engineering?

Answer 26

Articular cartilage doesn’t repair well.

Avascular
Aneural
No lymphatics

Question 27

Tissue engineering is for —— replacement.

Cell replacement is for —— replacement.

Answer 27

Tissue engineering is for mechanical replacement.

Cell replacement is for biochemical replacement.

Question 28

Tissue engineering technique = ——— + ———- + ————

Answer 28

Tissue engineering technique = cells + biocompatible scaffold + mechanical stimuli

Question 29

Name the sources of cells used for tissue engineering.

Answer 29

Autologous
Allogenic
Xenogenic

Question 30

Name source of cell used for tissue engineering described below:

From the person who is having the replacement

No rejection issues but sometimes a slow growth process

Answer 30

Autologous

Question 31

Name source of cell used for tissue engineering described below:

Donor from the same species

Answer 31

Allogenic

Question 32

Name source of cell used for tissue engineering described below:

Donor from a different species

Answer 32

Xenogenic

Question 33

Scaffold for tissue engineering;

Allows cells to ——-
Allows ——–/—— delivery
Can apply ——— loads

Answer 33

Allows cells to attach
Allows nutrient/waste delivery
Can apply mechanical loads

Question 34

What are the types of scaffold for tissue engineering?

Answer 34

Collagens
Alginate (gels)
Hydropolymer