Skeletal system

Question 1

are bones living tissue?

Answer 1

Yes

Question 2

Are bones connective tissue?

Answer 2

yes

Question 3

what are the functions of the skeletal system?

Answer 3

1. Structure/Support
2. Protection
3. Movement (body levers)
4. Mineral storehouse( for Calcium, Phosphate)/ Calcium Homeostasis
5. Blood cell production (hematopoiesis)

Question 4

example of a long bone
example of short bone 
example of flat 
example of irregular 
example of sesamoid

Answer 4

• femur
• carpal bones in hands, tarsals in feet
• sternum
• vertebrae
• patella

Question 5

What are the cells of interest in terms of bone/skeletal system?

Answer 5

Osteogenic cell ==>osteoblasts–>osteocyte–> osteoclasts

Question 6

What is an osteoblast? What is the general role of an osteoblast?

Answer 6

“Bone-builders”–> DEPOSITION (via secreting collagen fibers and other organic components)

• Growth
• Repair
• Remodeling
• -> form the bone extracellular matrix

Question 7

What is an Osteocyte? And what is the general role of an osteocyte?

Answer 7

• A mature bone cell,

- Maintenance/ maintains the bone tissue

Question 8

What is an Osteoclast? General Role?

Answer 8

“Carve out bone” –> Osteoclasts: Resorption(breakdown of bone extracellular matrix)

• Unloading
• Repair
• Remodeling

Question 9

Can osteons be found in trabeculae ?

Answer 9

No! only in compact bone

Question 10

Inner surface of a bone called?

Answer 10

Endosteum (also contains osteoblasts, clasts, and cytes)

Question 11

Outer surface of a bone called?

Answer 11

Periosteum

Question 12

what is bone made of??

Answer 12

1. Bone cells : cytes, blasts, clasts, osteogenic

2. ECM: Organic and Inorganic

Question 13

What are the components of Organic Bone ECM? (healthy)

Answer 13

30%

• Collagen ( type 1 )
• Gel

Question 14

What are the components of Inorganic Bone ECM? (healthy)

Answer 14

70%

Hydroxyapatite –> mineralized form of calcium and phosphate

Question 15

list different types of mechanical loading of a bone

Answer 15

1. Compression
2. Tension
3. Shear
4. Torsion
5. Bending

Question 16

Define Bone Strength (in regards to load-deformation graph)

Answer 16

-Load at the failure point

Question 17

Define Bone Stiffness/Rigidity

Answer 17

• Slope

- Load required to deform a bone at a given amount

Question 18

Define Toughness

Answer 18

• Area under the load-deformation curve

- Energy required to yield or fracture the bone

Question 19

Brittle Bone composition?

Answer 19

70% inorganic, 30% organic

Question 20

what is compact bone tissue STRUCTURE consist of?

Answer 20

Structural units of osteons (haversian systems)

Question 21

where are osteocytes located?

Answer 21

Within the concentric lamellae of an osteon

Question 22

what are lacunae?

Answer 22

Lacunae is the space between an osteocyte and lamellae

Question 23

How do osteocytes communicate and receive and transport nutrients?

Answer 23

Via the cannaliculi which run horizontally connecting the osteocytes towards each other and throughout the bone

Question 24

another name for perforating canals?

Answer 24

Volksmann’s canals

Question 25

volksmann canals structure?

Answer 25

They run perpendicular to the central canals, and connect each canal towards the outer surface of the compact bone (periosteum)

Question 26

Purpose of volkmann's canals?

Answer 26

Used as means for blood vessels, lymph vessels, and nerves to supply the compact bone.

Question 27

what are sharpey's fibers made of and function?

Answer 27

They are thick bunds of collagen, and supply the outside of the bone (periosteum) with nutrients to assist in bone repair/remodeling.

Question 28

another name for spongy bone tissue?

Answer 28

trabeculae

Question 29

Do trabeculae have osteons? Why or why not?

Answer 29

NO, they are not nearly as dense as compact bone already have a lot of space.

Question 30

Is spongy bone most of the time within a bone? or outside of a bone?

Answer 30

Interior of a bone.

Question 31

How can diet affect bone composition (in context of organic)

Answer 31

Protein and Vitamin C help create more collagen

Question 32

How can diet affect bone composition (inorganically)

Answer 32

Lack of Calcium and Vitamin D --> affects the mineral composition and can weaken of soften bones ( ie rickets and osteomalacia)

Question 33

Why is spongy bone so important??

Answer 33

Red bone marrow

Question 34

Why is red bone marrow so important?

Answer 34

Blood cell production ! (hematopoesis)

Question 35

Why is bone considered a living tissue?

Answer 35

Because it is adaptive: they undergo - growth - repair (macro/microdamage) - Remodeling

Question 36

What do you mean by remodeling?

Answer 36

Bone remodeling is formation of new bone tissue and the breakdown of old bone tissue

Question 37

Explain the 4 cell types of bone tissue

Answer 37

Osteogenic cells --> progenitor bone cells that develop into osteoblasts - osteoblasts - build new bone/ forms the bone ECM via secreting collagen and entrapping themselves within a matrix to mature into osteocytes - osteocytes - maintain the bone tissue, theyre the main cells in bone tissue, regulate exchange of nutrient and waste of bone tissue with blood - osteoclasts -resorption ie. carve out/break down bone (via lysozomal enzymes), releasing Ca+ as a product.

Question 38

What and where is the yield point on Load-Deformation graph?

Answer 38

Yield point is the pt at the end of the elastic, and start of plastic region. It is the amount of load in which a bone will begin to fracture permanently and no longer elastic

Question 39

What and where is the failure point on Load-Deformation graph?

Answer 39

The failure pt is at the end of the plastic region: and it signifies the point at which actually breaks/fracture

Question 40

How do I find the maximum deformation of a bone?

Answer 40

It is the number drawn vertically from the failure point.