MSK: Week 3 Flashcards
What variables affect muscle contraction
- Length
- tension
Define Isometric Contraction
Contraction where tension changes but muscle length stays the same
Define isotonic contraction
Contraction where muscle length changes but tension stays the same
Define concentric contraction
Where muscle length shortens
Define Eccentric contraction
Where muscle length increases
Is the axon terminal of motor neurons myelinated
Yes
Where are acetylcholinesterase located
On the post-synaptic membrane junctions in the motor end plate
What are three biological roles of myosin
- Assembles into fragments
- Uses ATPase enzymes
- Binds to actin
Describe the structure of myosin
Has two heavy chains
Has four light chains
How large are the heavy chains on myosin
200,000 MW
What are the sizes of the light chains
1 pair = 16,000 MW
1 pair = 20,000 MW
Describe the structure of actin
F-actin filament consisting of G-actin monomers
F-actin filaments make a chain of two alpha helices
What is the size of a single G-actin monomer
41,800 MW
What structure is wrapped around the F-actin alpha helices
Tropomyosin
What is the role of Titin
Connects the Z-line to the M-line in the sarcomere
M-line = Middle of the sarcomere
It prevents over-stretching by recoiling
What is the molecular size of tropomyosin
35,000 MW
How often does a troponin complex appear along the tropomyosin chain
Every 38.5nm along
What does a troponin complex consist of
- TnI - Inhibitory
- TnT - Binds to tropomyosin
- TnC - Binds to calcium
Define fracture
Breach in continuity of bone
Name two ways fracture occur
Non-physiological loads applied to normal bone
Physiological load applied to abnormal bone
How do I describe on what part of the bone the fracture is located
Proximal 1/3
Middle 1/3
Distal 1/3
Define the following fracture names: Transverse Oblique Spiral Communicate Segmental Avulsed Impacted Torus Greenstick
- A transverse cut through the bone
- A diagonal cut through the bone
- A curved cut through the bone
- A crack on the bone
- Cuts through the bone that breaks it into segments
- A piece of bone that breaks off the tips of the bone
- A cut through the tip of the bone
- A swelling in the bone
- A semi-cut through the bone (not all the way through)
Define fracture angulation
Where the normal axis of the bone has been altered such that the distal bone points in another direction
Define an intra-articular fracture
A bone fracture in which the break crosses into the joint surface
This damages the cartilage always
