Muscle Sensory Receptors Flashcards
What are the two type of muscle fibers that muscles contain?
Intrafusal
Extrafusal
What type of sensory endings do 1A fibers have?
Sensory endings that circle the middle portion forming the primary end
What do the bag 1 (nuclear bag) Intrafusal fibers sense?
Rate of change
What do the bag 2 (nuclear chain) fibers sense?
Fiber length
What fibers innervate the nuclear chain fibers (bag 2)?
II fibers
What fiber keeps the muscle spindle taunt?
Gamma fibers
What do type 1A fibers (primary end) do?
Respond to the rate of change in muscle length, as well to change in velocity, rapidly adapting
What do type 2 fibers (secondary end) do?
provide position sense of a still muscle, fire when muscle is static
Where are type 1B sensory fibers found?
In the Golgi Tendon Organ
What do gamma fibers do?
They contract to bring the spindle apparatus to its normal state (does not cause the muscle to contract)
What are the different type of stretch recognized by bag 1/2?
Nuclear bag (bag 1) sense onset of stretch Nuclear fibers (bag 2) sense sustained stretch Both respond to rapid stretch to stop muscle injury
What happens if bag 1/2 become slack?
They cannot transmit signals
What do type 1B sensory fibers do?
When there is tension on the tendon they send a signal to the alpha motor neurons that inhibit it and relieve tension
What do Renshaw cells do?
They are inhibitory interneurons of the antagonistic muscle
What does the GTO respond to?
Force not length
