Three factors that influence the rapidity and effectiveness of reflex arcs which these increases excitatory level spinal cord?

1. Strength of the stimulus: The stronger the stimulus, the faster and more effective the reflex arc. This is because a stronger stimulus will activate more sensory neurons, which will in turn send more signals to the spinal cord. The spinal cord will then send more signals to the motor neurons, which will cause the muscles to contract more forcefully.

2. Number of synapses in the reflex arc: The more synapses there are in the reflex arc, the slower and less effective the reflex arc. This is because each synapse represents a potential for delay, as the signal has to be transmitted from one neuron to the next. The more synapses there are, the more opportunities there are for the signal to be delayed or lost.

3. Excitatory level of the spinal cord: The excitatory level of the spinal cord refers to the degree to which the spinal cord is ready to respond to a stimulus. The higher the excitatory level, the faster and more effective the reflex arc. This is because the spinal cord will be more likely to send signals to the motor neurons when the excitatory level is high.

There are a number of things that can increase the excitatory level of the spinal cord, including:

* Caffeine: Caffeine is a stimulant that can increase the excitatory level of the spinal cord.

* Strychnine: Strychnine is a poison that can increase the excitatory level of the spinal cord.

* Electrical stimulation: Electrical stimulation can be used to increase the excitatory level of the spinal cord.

Increasing the excitatory level of the spinal cord can be helpful in treating certain conditions, such as spinal cord injuries and multiple sclerosis.