Reflexes - general question

[madman1611]

Hey, guys. I was just curious to know, why are some reflexes faster than others?

[MichaelXY]

Holding your hand in a flame too long would be bad.

[Draco]

Because reflex reactions which are the fastest travel by the fastest route possible and don't require conscious thought.

[MrMistery]

the fastest reflexes of all are termed monosynaptic reflexes - there is only one synapse(hence, two neurons) in the path. The common example is the rotulian reflex: one neuron in the ganglion near the spine, one motor neuron in the spine.
A more complicated reflex is the nociceptive reflex - pulling your hand away when you hold it in a flame. However, this one takes a little longer than the rotulian reflex because there are three neurons: one in the ganglion and two in the spine.
The more synapses, the longer it takes. Some unconscious reflexes have tens or hundreds of synapses, such as breathing reflexes, vomiting etc. However the key to understanding reflex lag time is the number of synapses.