Lab3 Flashcards
Give the steps in making isometric maximum curve
Supramaximal single stimuli and provide isotonic conditions in each step
What is the electromyogram (EMG)?
Potential differences from muscle contractions measured on the skin
When does complete tetany develop?
When the muscle doesn’t relax, but shows continuous tonic spasm
Maximal stimulus
The weakest stimulus strength that just causes complete contraction
Give the steps and principle in passive stretch curve to measure muscle function
Relative length determined by different weights
What happens when Ca binds to TnC?
Shift tropomyosin-troponin complex to the groove of the actin filament
Which muscle and which nerve is used in the classical frog-nerve experiment?
M.gastrocnemius and sciatic nerve
Explain the importance of the muscle reacting to different threshold potentials
The “all-or-none” law of the muscle fibers
All or none law
Contracting maximally
Physiological reason for muscle fatigue
Increasing concentration of metabolic by-products
Steps of the “cross the bridge” cycle
Formation of actomyosin complex, sliding of filaments and dissociation of ATP-dependent terminal phase
Latency period
Time period between the stimulus and the start of contraction
What is meant by temporal summation?
Superposition
What is the length tension curve?
Diagram with passive stretch curve, isotonic max curve and isometric max curve
Which muscle exhaust latest?
Red muscle with slow-twitch fibers
What is superposition?
Repeated stimulation before previous calcium transient has finished, give additional calcium release and increase concentration
The three curves in measuring length-tension
Passive stretch curve, isotonic max curve and isometric max curve
Briefly explain the passive stretch curve
Relative length of muscle for each weigh
Red muscle
Oxidative with slow-twitch fibers
White muscle
Glycolytic with fast-twitch fibers
Which ion increases in the myoplasm as the action potential reaches the muscle?
Calcium
How do we find the minimal stimulus of a muscle?
Increase stimulus strength gradually between 0 and 500 mV
What is minimal stimulus?
The weakest stimulus strength that just elicits contraction
