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Criado por J yadonknow
mais de 6 anos atrás
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Questão | Responda |
Key components of a reflex arc: | Sense organ Afferent neuron Synapse Efferent neuron Neuro-muscular junction Muscle |
Reflex Arc (6) | Generator P AP EPSP (and IPSP) AP End-plate P AP |
MOA (7) | 1. Sense organ generator pt 2. Stim large enough - aff fires AP 3. Aff releases neurot at synapse 4. If neurot bind to R in post-synaptic term then EPSP. 5. AP propagated along Eff 6. epsp at end plate = endplate potential 7. Propagated along muscle generating AP |
Knee-jerk reflex is an example of a | Mono-synaptic reflex |
What's the stimulation? | Stretching of the patella tendon |
What does this cause? | Stretching of extensor muscle |
How is stretch sensed? | By muscle spindle |
What does this activate? | Afferent 1a sensory nerve |
What does this go on to stimulate and how? | 1a releases excitatory neurot from collaterals which synapse onto excitatory neuromuscular junctions |
What do these do? | Release Ach onto extensor muscle, causes it to contract |
Where else do collaterals secrete exc neurot? | Onto inhibitory synapses |
What's the result? | inhibitory neurot released onto excitatory neuromuscular junction Flexo relaxes |
What's the name of this time of inhibition and excitation? | Reciprocal inhibition |
How does GABA work? | Inhibitory neurot + Cl- channels Lowers AP |
Polysynaptic Spinal Reflex stimulus standing on tack | Stimulus + painR in heel |
MOA flexor contraction | Sensory afferent neuron collaterals synapse with other neurons in the spinal chord Release exc. neurot onto flexor muscle motor neurons Flexor motor neurons release Ach onto muscle Flexor contracts |
Why need reciprocal inhibition? | Antagonistic pair necessitates reciprocal inhibition |
Reciprocal inhibition | Sensory afferent also releases exc. neurot onto inhib. synapse Release inhib neurot onto extensor motor neuron |
Balance | As balance needed, sensory neurons communicate w/ interneurons on opposite side of spinal chord Activates motor neuron innervating extensor and inhibits flexor |
What is the knee-jerk test used for? | Test if LMN are working |
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