Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

34 Cards in this Set

  • Front
  • Back
How are limb movements produced?
By the coordinated contraction of groups of muscles working together.
What happens as synergists contract?
Antagonists relax.
2 types of muscles:
What is the Stretch Reflex? (clinical name?)
A monosynaptic excitatory reflex
-Deep tendon reflex
What is the common example of a stretch reflex?
The patellar reflex
What is the STIMULUS in the stretch reflex? Receptor?
-STRETCH of muscles which increases its length
-Receptor is Muscle spindles
What is the AFFERENT in the stretch reflex?
Ia afferents from the muscle spindle.
Where does the Ia afferent project? (3 places)
-To almost all a-motor neurons that control the muscle where the Ia afferent signal started
-To synergistic muscles
-To inhibitory interneurons that inhibit motor neurons to antagonist muscles
What do we call that muscle where it all started?
Homonymous muscle
What is the Efferent in the stretch reflex?
The alpha motor neurons that excite the homonymous and synergist muscles to cause contraction.
What is this Reciprocal innervation?
Simultaneous excitation of a group of synergistic muscles and inhibition of their antagonists.
Why do we need the monosynaptic reflex?
To maintain muscle tone for posture, to hold still, to smooth out movements.
What is the function of the Flexion and Crossed-Extension reflex?
Withdrawal from a painful stimulus.
Is the Flexor reflex monosynaptic?
No it is polysynaptic
What is an example of the flexor reflex?
A nail in the knee makes you draw back and shift weight to your other leg.
What is the receptor that is stimulated in the flexor reflex?
What happens with the afferent information from nociception?
It goes to interneurons in the spinal cord that do 2 things:
-excite ipsilateral flexor muscle
-inhibit extensor muscle
What is achieved by exciting the ipsilateral flexor and inhbiting the extensor muscles?
You withdraw
What do contralateral interneurons do?
-Excite contralateral extensor
-Inhibit contralateral flexor
What is achieved by exciting the ipsilateral extensor and inhbiting the flexor muscles?
You have a leg to stand on!
What's pretty remarkable about the Flexor Reflex?
It remains even if you completely transect the spinal cord.
So what does a Muscle spindle activate?
Alpha motor neurons
What does a Golgi tendon organ reflex in contrast do?
Inhibits alpha motor neurons via inhibitory interneurons.
What is the stimulus for the Golgi tendon organ reflex?
Tension on the Golgi tendon organ receptor
What is the afferent in the Golgi tendon organ reflex?
Ib afferent inhibitory interneurons.
Do these Ib afferent inhibitory interneurons stand alone?
NO! they also get convergent info from muscle spindle afferents, low-threshold cutaneous afferents, joint afferents, and UMN pathways.
What does activation of inhibitory Ib interneurons do ultimately?
Inhibits the homonymous muscle - the original one - that was stretched.
What is this inhibition called?
Autogenic inhibition.
What is the FUNCTION of the Golgi tendon reflex?
To prevent overly forceful movements, and precisely control fine movements.
What do Ia afferents inhibit during the stretch reflex?
Antagonist muscles
What do Ib afferents inhibit in the Golgi tendon reflex?
Agonist muscles
What are Renshaw cells?
What do Renshaw cells do?
Inhibit the same motor neurons that excite Renshaws in the 1st place, to give negative feedback.
Why do we have Renshaw cells?
To regulate the firing pattern of motor neurons, and make sure the a-motor neurons in our motor pools TAKE TURNS.