What occur during reflex arc?

Answer 1

Definitions:

1. afferent neuron - sensory nerve

2. efferent neuron - motor nerve

3. monosynaptic - see below

There are different types of reflexes but the simplest type is a monosynaptic reflex.

This means the afferent neurons connect directly to the efferent neurons.

For example the knee jerk reflex is a monosynaptic reflex:

1. The patellar tendon is stretched.

2. The afferent neuron (which has stretch sensors) send a signal up to the spinal cord.

3. In the spinal cord at the synapse. The electrical signal is changed to a chemical signal.

4. Chemical messengers travel across the synapse and stimulate the efferent neuron.

5. The efferent neuron changes these signals into electrical signals which travel down to the quadriceps muscle.

6. There is another synapse connecting the nerve to the muscle. chemical messengers travel across the synapse and stimulate the muscle to contract.

Answer 2

A reflex occurs when a stimulus causes the receptor to stimulate an afferent neuron in the peripheral nervous system. That afferent neuron then transmits an impulse to the spinal cord. The impulse will transmit through the ganglion then to the gray matter in the spinal cord. Two interneurons in the spinal cord will integrate information. One efferent neuron stimulates the flexor muscle to contract, and then the other efferent neuron sends inhibitory signals that keep the extensor muscles from contracting.

Answer 3

During a reflex arc, sensory receptors detect a stimulus and send a signal through a sensory neuron to the spinal cord. In the spinal cord, the signal is processed and a response is generated quickly through a motor neuron to the effector organ, causing a reflex action (such as pulling your hand away from a hot object) without involving the brain.