Block 2: Skeletal System - Lecture 2.3

Question 1

What is a Composite material, and what is an example within the Skeletal System?

Answer 1

Combination of a ceramic (inorganic) and a polymer (organic)
a. combination allows for very strong & slightly flexible matrix
b. provides maximum bone strength
Example: Osseous Matrix

Question 2

What would happen if the Osseous Matrix only contained Inorganic materials?

Answer 2

Very strong but inflexible
a. shatter easily

Inorganic (minerals) materials provide stiffness!

Question 3

What would happen if the Osseous Matrix only contained Organic materials?

Answer 3

Tough but too flexible
a. would not resist direct pressure

Organic (collagen) materials provide flexibility!

Question 4

What is the most distinguished property of the Osseous Matrix?

Answer 4

Contains sacrificial bonds between collagen molecules that break under mechanical stress, but can reformed once stress is removed
a. breakage under mechanical stress –> removes mechanical force –> reduces likelihood of fracture

Question 5

What are two skeletal disorders associated with deficiencies in the Osseous Matrix?

Answer 5

Rickets & Scurvy

Question 6

What skeletal disorder is caused by an Inorganic material deficiency?

Answer 6

Rickets

Question 7

What skeletal disorder is caused by an Organic material deficiency?

Answer 7

Scurvy

Question 8

What is Rickets?

Answer 8

Non-contagious skeletal disorder caused by Inorganic material deficiency
a. specifically calcium deficient due to lack of vitamin D
b. leads to flexible bones
c. can be fixed, but after growth plates close it may become permanent

Question 9

What is Scurvy?

Answer 9

Non-contagious skeletal disorder caused by Organic material deficiency
a. problems with collagen synthesis due to lack of vitamin C
b. leads to brittle bones that can fracture easily

Question 10

What is the most common structure in Compact Bone?

Answer 10

Osteons!
a. smallest unit of bone that provides most functions
b. concentric lamellae surround central canal
c. canaliculi connect concentric lamellae
d. perforating canals osteons

can be in spongy bone, but mostly compact

Question 11

Why do Concentric Lamella have very strong support?

Answer 11

They contain fibers that alternate directions

Question 12

What are the functions of Perforating Canals?

Answer 12

Connect Osteons to each other and their medullary cavities
Moves blood throughout bone

Question 13

What happens when Osteons get very old?

Answer 13

They get remodeled into Interstitial Lamellae

Question 14

What are the 3 types of Lamellae in Compact bone?

Answer 14

Concentric Lamellae: surrounds osteons
Circumferential Lamellae: surrounds all internal and external bone surfaces in 3-5 layers
Interstitial Lamellae: Fills gaps between osteons and is usually made up of fragments of old osteons

Question 15

What are the two most common structures in Spongy Bone?

Answer 15

Spicules & Trabeculae
a. thing silvers of branching plates that can be organized as lamellae in larger plates
b. open space for mineral storage and functionalities
c. interconnected spaces
d. contain the same cells as compact bone
e. very strong (protection), but very light weight

Question 16

What are the key differences between Compact Bone and Spongy bone?

Answer 16

Compact Bone:
a. dense
b. covers bone surface
c. thick where stress is high
d. handles stress in one direction

Spongy Bone:
a. lightweight
b. handles stress in all directions
c. support for bone marrow and joints
d. fat & mineral storage and blood cell development

Question 17

How does the distribution of Compact Bone and Spongy Bone differ?

Answer 17

Compact Bone: thicker along the diaphysis
Spongy Bone: thin line through diaphysis and in epiphysis

Metaphysis separates Compact Bone and Spongy Bone in epiphysis