Muscle Part B Flashcards
(34 cards)
What are the Principles of Muscle Mechanics?
1.Same principles apply to contraction of a
single fiber and a whole muscle
2.Contraction produces tension, the force
exerted on the load or object to be moved
3.Contraction does not always shorten a
muscle: Isometric and Isotonic
4. Force and duration of contraction vary in response to stimuli of different frequencies
and intensities
Contraction produces tension, the force
exerted on the load or object to be moved
____?no shortening; muscle
tension increases but does not exceed the load
Isometric contraction
____?muscle shortens
because muscle tension exceeds the load
Isotonic contraction
Muscle changes in length and moves the load
____? contractions are either concentric or eccentric:
Isotonic Contractions
Muscle changes in length and moves the load
____? contractions are either concentric or eccentric:
Isotonic Contractions
When the muscle
shortens and does work is call
Concentric
When the muscle
shortens and does work is call
Concentric
When the muscle contracts
as it lengthens it becomes
Eccentric
When The load is greater than the tension the muscle is able to develop, what Contraction does it becomes?
Isometric contractions
When The load is greater than the tension the muscle is able to develop, what Contraction does it becomes?
Isometric contractions
Tension increases to the muscle’s capacity, but the muscle neither shortens nor lengthens what contractions does it become?
Isometric Contractions
Tension increases to the muscle’s capacity, but the muscle neither shortens nor lengthens what contractions does it become?
Isometric Contractions
___? a motor neuron and all (four to
several hundred) muscle fibers it supplies
Motor unit
___? a motor neuron and all (four to
several hundred) muscle fibers it supplies
Motor unit
motor units in muscles that control fine
movements (fingers, eyes)
Small Motor Unit
motor units in large weight-bearing
muscles (thighs, hips)
Large Motor unit
____?is a Response of a muscle to a single, brief threshold stimulus
Muscle Twitch
____?is a Response of a muscle to a single, brief threshold stimulus
Muscle Twitch
A single stimulus results in a single contraction response of a ____?
Muscle twitch
A single stimulus results in a single contraction response of a ____?
Muscle twitch
Three phases of a twitch are
1. Latent period: events of excitation- contraction coupling 2. Period of contraction: cross bridge formation; tension increases 3. Period of relaxation: Ca2+ reentry into the SR; tension declines to zero
Define: Increase frequency of stimulus
when muscle does not have time to completely relax between
stimuli
when ATP is the only source used directly for contractile activities it becomes?
Muscle Metabolism
