Midterm #I Flashcards
Surface EMG
Electrode placement over muscle belly easy to apply and comes in various sizes
EMG clinieal use
Can be used for diagnosis
-tingling
-numbness
- weakness
- cramping
Can determine
-disorders
- nerve dysfunction
-neuromuscular
How do you measure EMG
EKG on muscle belly and picks up contraction of muscles/electrical activity - raw signal from electronode of many muscles, need to isolate specific muscles
What is acceleration and now do you calculate it?
Rate of change of velocity m/s
What type of concentration exerts the most force
Concentric
* viscosity moves against contractile, creating a tense more forceful contraction
What is esentric contraction?
Muscle load is greater then force produced
EX) extension
*Viscosity moves with the contractile force
What does EMG stand for
Electromyography
Which contraction exerts no change
Isometric * no friction, no muscle shortening
What is a resultant
Hypotenuse
*can be found using Pythagorean once fx and fy are found using vectors
What is a vector
Magnitude and direction
What is the role of calcium
Trigger to initiate the contractile process in skeletal muscles -as long as calcium is present, the muscle will contract
Trophyosin covers binding sites, once calcium binds to trephine it uncovers the binding site on actin so it can undergo cross bridge and power stroke
What is a powerstroke
Myosin head of one thick filament flexes to blend. While releasing ADP and inorganic phosphate,pulling the thin filament along with it
- when actin and myosin bind
What is a sacromere
Bundle of myosin and actin that go through power bridge
What are the 2 principles of contractile proteins in skeletal muscles
Protein that contract to produce force. Bind together to help contract muscles
Actin = thin filaments
Myosin = thick filaments
Myosin needs attachment site for actin
Intrinsic factors that effect EMG signal
- number of active MU
- fiber composition
-blow flow - fiber diameter
- distance between fibres and electrodes
Pennate facile organization
Rotate about tendon attachment when contraction which causes angle to increase
- higher fiber per unit of muscle volume
Indwelling EMG
Conger recordings of specific or deeper muscles
Disadvantage
-painful
-Invasive
- not representation of whole muscle
Extrinsic factors that effect EMG signal
- distance between electrodes
- placements
-Skin prep - sweat
- temp
Parrell facile organization
Have fibres running longitudinal axis with interconnections
Enable greater shortening of the entire muscle than pennate larger ROM
Motor unit refers to what
A single motor neurone and all the muscle fibres it innervates
The tissue surrounding the muscle is known as
Epimysium
