the brain
The knee-jerk reflex is controlled by the interneurons in the spinal cord.
Skeletal muscles interact with the spinal cord
A nerve impulse travels toward the actual nucleus itself to pass information.
The nerve impulse typically travels from the sensory neuron to the spinal cord, where it is processed by interneurons, and then to the motor neuron to elicit a response from the effector organ or muscle.
The nerve impulse from your foot to your leg is called a sensory nerve signal or proprioceptive feedback. It helps transmit information about sensations such as touch, pressure, and position to the brain.
nerve impulse
Reflex nerve pathway is a monosynaptic transmission. There are no interneurons involved. Only the limb that carries the afferent nerve impulse from the stimulus and the efferent motor function for the reflex involved. That is why it is faster. Normal nerve transmission require an interpretation of the impulse by the brain whereas reflex pathways do not. Another reason is because most reflexes from the exteroreceptors travel along myelinated axons (white matter) which carry the impulse faster than other neurons that have unmyelinated axons (grey matter).
nerve impulse
A reflex arc doesn't go all the way up to the brain. Thus it NEVER becomes part of the thought process.
The speed of impulse in a reflex arc can vary, but it is usually very fast, allowing for quick responses to stimuli. In general, impulses can travel at speeds of up to 100 meters per second along myelinated nerve fibers.
a nerve impulse
The process is called a knee jerk reflex. It is a simple reflex that occurs when the patellar tendon is tapped, resulting in the lower leg kicking forward involuntarily.