Flashcards in Physiology Quiz 3 (2/2) Deck (31):
Carry info away from CNS
A single motor efferent nerve and the muscle cells it innervates
Small motor units = _______ motor activity
Large motor units= ______ motor activity
What part of the body has the smallest motor units?
Muscles controlling the eye (4 muscle cells/1 motor efferent)
What part of the body has the largest motor units?
Some of he trunk musculature (1000 muscle cells/1 motor efferent)
Concentric muscle activity
Development of force by the muscle as it shortens
Example of concentric muscle activity
Bringing the weight up during a bicep curl
Eccentric muscle activity
Development of force by the muscle as it lengthens
Example of eccentric muscle activity
Lowering the weight during a bicep curl
What type of muscle activity uses more energy? (Concentric or eccentric)
Which type of muscle activity is easier to learn motor control of? (Concentric or eccentric)
Delayed onset muscle soreness
When does DOMS peak?
48-72 hours after activity
What is DOMS caused by?
Repair of microtears in series elastic element (SEE) mostly caused by eccentric activity (less often with concentric). This microtearing causes inflammation, swelling, pain, and scarring
Shortens and returns to original configuration
Stretches, but it will reach a certain point where it will not return to original configuration
Point a series elastic element stretches to where it will still return to original configuration; any further and it will not return to original configuration
Is plasticity good?
Yes, it can help with flexibility
Series elastic element
Structures that have the property of elasticity
-connective tissue sheaths or muscle and myofibrils
How is force transmitted in concentric activity?
It will absorb some force and transmit the rest (think about rubber band pulling water bottle water bottle)
How force is transmitted during eccentric activity
Develops force because it is undergoing a stretch force and thereby adds to the force developed eccentrically
Source of force in concentric activity
Source of force in eccentric activity
SEE recoil (mostly this one)
Which type of muscle activity uses less energy (eccentric or concentric)
Random laying down of collagen fibrils as a scar forms
Laying down of collagen fibrils in an organized and controlled manner
Less loss of ROM
Stretching helps develop this
As muscle develops force, distance between origin and insertion does not change (fibers still shorten)
Example of isometric contraction
Muscle changing length but maintaining same force throughout movement