Neurons- III. Classification

Question 1

A. STRUCTURAL

Answer 1

based on the number of processes that come off of the cell body

1. bipolar
2. unipolar
3. multipolar
4. anaxonic

Question 2

B. FUNCTIONAL

Answer 2

based on the direction of the nerve impulse (a.p.)

1. Sensory neuron= Afferent neuron
   a. source of stimulus: somatic (skin receptors monitor outside world toward afferent C.N.S. and visceral (monitors inside)
2. Motor neuron= efferent neuron
   a. type of target organ: somatic (if going to skeletal/voluntary muscles to change position in outside world) and visceral (if going to cardiac muscle, smooth muscle, or gland, all of which are involuntary
3. Interneuron

Question 3

C. LOCATION

Answer 3

1. Afferent- Somatic and Visceral
   a. 1st order
   b. 2nd order
   c. 3rd order
2. Efferent
   a. upper motor neuron
   b. lower motor neuron
   i. somatic efferent
   ii. visceral efferent: presynaptic neuron (preganglionic neuron) and postsynaptic neuron (postganglionic neuron)
3. Connections in and to the brain
   a. Association fibers ex: arcuate fibers
   b. Commissural fibers ex: corpus callosum, anterior commissure
   c. Projection Fibers ex: internal capsule (in brain) forms tracts and columns in spinal cord