Lab 5: Muscle

what did we use to electrically simulate our nerves of our forearm?

Isolated stimulator

The hand dynamometer was used to examine what?

grip force and the ability to sustain it under different conditions

How is muscle connected to the bone?

through a tendon

What is a strong bundle of collagen fibers called?

a tendon

t/f two or more muscle work antagonistically

True

give an example of two muscles working antagonistically.

the tricep and bicep.

[when the bicep contracts/shorten, the tricep elongates]

what are the components of muscles (smallest to largest)

myofilaments

what type of connective tissue covers muscle fibers?

Endomysium

[think.. endo = inner // muscle fibers are *IN* muscle fascicles]

what type of connective cells cover a muscle fascicle?

Perimysium

[think peri= perimeters ]

Epimysium covers what muscle structure?

skeletal muscle

[think.. epi= outer // outer as in whole muscle ]

Describe what a motor unit is

a single motor neuron and the muscle fibers it innervated

How do motor neurons affect action potentials in muscle fibers?

motor neurons release acetylcholine to induce action potential in muscle fibers

when acetylcholine is released what happens to the muscle fiber?

There is a brief increase of intracellular concentration of Ca2+

what is a twitch?

a single muscle contraction from a single stimulus

what is recruitment?

gathering of several motor units in order to create a strong contraction

what is summation?

rapid stimulation that does not allow a muscle to completely relax, thus creating a increased force.

[think... sum = adding ]

what is tetanus?

several twitches with no time to relax in between, which creates a smooth contraction.
Summation leads to tetnaus


(looks like this ,--------, instead of this /\/\/\/\)

put these tissues in order from most inner to most outer

perimysium, epimysium, endomysium

endomysium

connective tissue that surrounds muscle fascicles is called?

perimysium

t/f skeletal muscles are striated

True

the amount of stimulus necessary to elicit a maximal response in skeletal muscle is called what?

maximal stimuli

which procedure do we use to measure electrical activity of skeletal muscle?

electromyogram or electrocardiogram?

ElectroMYOgram

[myo = skeletal muscle // cardio = cardiac msucle ]

contraction of a muscle leads to more minor activity in the antagonist muscle is called hat?

Coactivation

[think antagonist needs two... two = co]

t/f in one of the muscle contraction labs, we measured the effects of a brief rest, visual feedback and verbal encouragement on grip force

True

[think of when zane reached 101% when we cheered for him]

t/f the speed at which an electrical impulse travels along a nerve is measured in m/s and is called contraction strength

false

[it is called electroneurography (EneG) or never conduction velocity (NVC) ]

Explain how motor neuron causes an action potential in a muscle fiber that results in contraction

-When an AP is fired in the motor neuron, Acetylcholine is released to bind with muscle fiber receptors
-Causes Na+ channels to open and Na+ defuses into the muscle fiber
-this depolarizes muscle fiber and creates AP
-Ap causes contraction

Define threshold stimulus

amount of voltage necessary to elicit a response from the muscle

Define Suprathreshold stimulus

a stimulus above threshold stimulus

Define Submaximal stimulus

the amount of voltage necessary to elicit a response above threshold but below maximum response

Define Maximal stimulus

stimulus necessary to elicit a maximal response