Final Exam Review Old Material Flashcards
What is spatial summation of PSP’s?
When would an action potential be generated?
Two different neurons simultaneous stimuli at different location cause PSP that add together.
When they are excitatory and fire and add together to reach threshold
What is Temporal Summation of PSP’s?
Describe an example when an action potential would be generated?
Same cell Two excitatory stimuli close in time cause EPSP’s that add together *does not have to be excitatory; it could be inhibitory PSPs that add together and push the membrane potential farther away from threshold
Fire close in time from one cell to reach threshold
Role of Myelin
Insulates
Saltatory Conduction
Myelinated
Fast - because of the myelination it is faster
Continuous Conduction
NOT Myelinated
Slow - because it has to move through every single step
Describe the structures and neurotransmitter involved in the neuromuscular junction and what makes this unique compared to neuron-neuron synaptic connections
Alpha motor neuron synapses on muscle fiber, acetylcholine (Ach) is released and an all or none response (if alpha MN fires, muscle fiber will contract)
What are the four steps from
stimulus to AP generation of mechanoreceptor?
4 steps:
1.stimulus is applied
2.deformation of the receptor or nerve endings
3. receptor potential generated
4. action potential generation
Corticospinal tract - Lateral
1) originate
2) terminate
3) decussation level
4) function/role for movement:
Lateral
1) Originate - Primary Motor Cortex
2)Terminate - Spinal Motor Nuclei on contralateral side
3)Decussation Level - Crosses up in the medulla
4)Function//Role - Limb Movement
Corticospinal tract - Ventral
1) originate
2) terminate
3) decussation level
4) function/role for movement:
Ventral
1) Originate - Primary Motor Cortex
2)Terminate - Crosses over where it is going to synpase - Spinal Motor Nuclei on ipsilateral side
3)Decussation Level - Terminal Level
4)Function//Role - Trunk/Axial Movement
Vestibulospinal tract – Lateral
1) originate
2) terminate
3) decussation level
4) function/role for movement:
Lateral
1) Originate - Vestibular Nuclei
2)Terminate - Flexor and Extensor Muscles
3)Decussation Level - (Same Side) No cross over so no level
4)Function//Role - Mediate postural adjustments; coordinate orientation of head and body in space
Generates excitatory for extensor muscles
Inhibitory for flexor muscles
Vestibulospinal tract – Medial
1) originate
2) terminate
3) decussation level
4) function/role for movement:
Medial
1) Originate - Vestibular Nuclei
2)Terminate - Bilateral input to LMN for neck muscles
3)Decussation Level - Where is synapses
4)Function//Role - Stabalizes head, Cordinate Head, eye movements
Size Principle for Inward Current -
CHECK?????
What makes it smooth?
IMPORTANT (Small motor units Will drive to threshold faster than large motor units because it has less resistance) (Alpha motor neurons fire)
Same inward current (I) from interneuron
- Smaller MN
- Smaller surface area
- Higher Resistance
- Results in large EPSP that reaches threshold and generates an action potential
Describe motor unit (MU) rotation –
What is it?
What does it do?
What is the result of it?
Inverse relationship of active motor units and mean of firing
Allows constant muscle force. A change in the number of recruited motor units correlates
(negatively) with their mean frequency of firing
The result of motor unit rotation = constant force level
What is a synergy?
Pattern of movement/muscle contractions
Electrical activity that we can read from the muscle - understand how movements are created
What are the parts of the Equilibrium Triad?
Vestibular System
+ Visual System
+ Proprioceptors
