Spinal reflexes

The reflex arc, stretch reflex, inverse stretch reflex, flexion and crossed extension: the responses the cord gives on its own.

The outline, topic by topic

Each topic is weighted the way the exam weighs it.

Reflex arc: what is it?
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The path of a signal from a receptor to an effector through the cord.
The response happens without any voluntary control.
The stretch reflex arc: which step comes after "Muscle stretch"?
- Muscle spindle excited
- Signal in the sensory neuron
- Synapse with the motor neuron in the cord
- Signal in the motor neuron
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Muscle spindle excited
The stretched muscle contracts: the principle of the knee-jerk.
Stretch reflex: what is it?
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A muscle contracting in response to its own stretch, sensed by the muscle spindle.
The knee-jerk is the example.
The doctor taps the tendon below the kneecap and the leg kicks. Which reflex?
- The withdrawal reflex
- The stretch reflex
- The inverse stretch reflex
- A voluntary movement
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The stretch reflex
The tap stretches the quadriceps, which contracts.
Monosynaptic reflex: what is it?
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A reflex with a single synapse between sensory neuron and motor neuron.
It is the fastest.