Spinal+reflex+arc+9

__Spinal Reflex__

The spinal cord sends and receives information to and from the brain. It is continuous with the brain stem.

**__ 3 Types of neurons: __**

** 1) **** AFFERENT- ** sensory n  erves carry information from the __body__ to the __brain__.  ** 2) **** EFFERENT- ** motor nerves carry information from th e __brain__ to the __body.__ ** 3) **** INTERNEURONS- ** carry information between 2 neurons.

sciencephoto.com **__ Grey Matter __** - butterfly shaped center portion of the spinal cord. It is the location of CELL BODIES in the spinal cord.

**__ Dorsal Ganglion __** - dilated area. - site of the AFFERENT neurons CELL BODY.

**__ Ventral Nerve Root __**//** - **// the region from the spinal cord to the spinal nerve containing only MOTOR fibers. **__ Dorsal Nerve Root __** - the region from the spinal cord to the posterior spinal cord containing only SENSORY fibers. - dorsal ganglion is found here.

**__ Receptor __** - nerve ending that MONITORS CHANGES IN THE EXTERNAL ENVIRONMENT. - initiate a sensory neuron’s action potential

**__ Effector __** - tissue supplied by a motor neuron

sciencephoto.com **__ Spinal Nerve __** - sensory information travels up the afferent fiber and directly stimulates the efferent neuron in the anterior grey horn of the spinal cord. - Efferent fiber then sends a signal to a muscle to move the body.