SpinalBioMech Midterm 2 Lec 4-7 Flashcards
Define Mechanical Advantage
Measure of mechanical effiency of a lever system
What is a mechanical advantage dependent on?
the type of lever system & the relationship btw the torque of an external force & the torque of a muscular force
(determined by length of MAs)
M Ad means?
mechanical advantage
What does EA stand for
Effort Arm
RA stands for ?
Resistance arm
Third class levers do what type of action?
Concentric Contraction
+>1 = mechanical _________
Advantage
0< 1 = mechanical ____________
disadvantage
Second class levers do _________ movements
eccentric
Which lever system is always at disadvantage?
Third-class levers
The effort force magnitude must always exceed the _______ ________ magnitude
Resistance force
The effort force magnitude must always _______ the resistance force magnitude
exceed
The third class lever systems the mechanical advantage is (less/ greater) than one
LESS
Second class levers are always at the mechanical _______
advantage
The mechanical advantage of of a second class lever is ______ than 1
M Ad = greater than one
First class levers can be at mechanical advantage, disadvantage, or neutral.
they are most often at mechaical ______
disadvantage
_______ chain has one end of segment or set of segments is free to move in space
Open chain
Open chains are :
where one end of the segment is free to move in space
Define closed chain
both sends of the segment are not free to move in space
1st class:
vs.
2nd class:
vs.
3rd class:
1st class: advantage, disadvantage, neurtal
2nd class: always mech. advantage
3rd: always disadvantage
The fxn of a joint is dependent on what 2 variables ?
- structure (design)
- Composition (materials)
More mobility of a joint = ______ stability
Less
The more stable a joint = _______ movement
less
Adaptation of bone to demand is ________ Law
Wolff’s Law
Wolff’s Law:
” Every change in the fxn of a bone is followed by certain definite changes in its internal architecture and its external conformation.”
bone & collagen have electrical fields which exhibit _____ _______
Piezoelectic properties
bone and collagen are made of ______ and _______ materials, which have electrical fields that exhibit piezoelectric properties
crystalline and semicrystaline
Increase tension on bones causes a ______ effect
anode effect (+)
Increase compression on bone causes a ______ effect
cathode (-)
What are the 4 classes of Human CT
- CT proper
- Cartilage
- Bone
- Blood
CT proper varies in _______ & _______
Density & elasticity
What are the three CT types of cartilage
hyaline, elastic, fibrocartilage
What is the hardest CT?
Bone
Name the 2 types of bone
- Compact- cortical
- Spongy - cancellous, trabecular
another name for compact bone
cortical
another name for spongy bone
cancellous, trabecular
What is the most abundent protein in the body
Collagen
Main substance of CT and some times refered to as the glue of the body ?
collagen
Collagen accounts for ___ - ____ % of all protein found in mammals
25-30%
Do ligaments have more collagen or elastin
collagen
________: few cells with much extra cellular material / matrix (ECM)
Ligaments
_________: are ostly collagen with some elastin
ligaments
__________ : connect muscle to bone
tendons
________: flat sacs of synovial membrane containing snovial fluid
bursea
What type of substance are in bursea?
synovial
________ is white cartilage
Fibrocartilage
_________: tough with limited molbility; occurs in jts with limited mobility
Fibrocartilage
Articulating cartilage is _____
hyaline
_________ : tough & very smooth; occurs at the ends of bone. Reduces friction
hyaline
Yellow cartilage is _______
elastic
_______: very flexible & resilient; occurs in ears, nose and skin
elastic
ligaments are:
_____% celluar
20 %
Ligaments are _____% extracelluar
80%
Fxn of extracellular matrix
provides structural support for cells, attract and binds water
