Lab Exam- Skeletal muscle function Flashcards
What is threshold stimulus?
The smallest stimulus that will produce a response (7mA for our experiment)
Max was around 18mA
What is a motor unit?
A single motor neuron and all of the muscle fibers that stimulate it
How is force of contraction controlled?
…
Force and type of contraction?
Isometric- The muscle contracts, but your joints do not move and the muscle fibers maintain a constant length
Isotonic- A body part is moved and the muscle fibers shorten or lengthen

What was the purpose of the skeletal muscle function lab?
How muscles function, electrical signals used to display twitch, recruitment, summation, and tetanus
What was needed for the skeletal muscle function lab?
- stimulus
- pulse transducer
- muscle/nerve
- Power lab to graph
- volunteer
What nerve did the electrode stimulate to display twitch?
What was the X and Y axis?
Ulnar nerve
X-  stimulus intensity (mA)/strength of contraction
Y- twitch force (T) 
What is summation?
When the second response is higher then the first response,
Repeated twitch contractions, where the previous twitch has not relaxed completely,
Each increase is getting bigger and adding on to the previous (sum)
 using more muscle fibers in parallel is called?
Recruitment
Maximal stimulus recruitment was achieved at 18 mA (graph leveled out, a plateau was seen due to tetanus)
At how many millisecond intervals was tetanus achieved?
50 ms (started at 1000 ms)
What time interval Produced summation? 
…
At threshold _______ muscle fibers are contracted. At maximal stimulus _____  muscle fibers are contracted. 
Some, all
What Hz is tetanus?
How do you calculate The velocity of nerve conduction?
The distance divided by the change in time
Why does varying the stimulus strength affect me twitch force?
With stronger stimuli, more nerve fibers are stimulated and therefore more motor units are recruited
