Question

Anatomy Tutorial: Neuron Classification

Answer 1

\({\bf{Classifications~of~Neurons:}}\) two types, structural and functional

Structural:
> anaxonic: axons and dendrites are indistinguishable. only in CNS and some sense organs.
> bipolar: cell body between axon and dendrite. dendrites fuse to form single dendrite. sensory information for sight/smell/hearing
> pseudounipolar: initial segment where dendrites converge. cell body off to the side but still between axon + dendrite.
> multipolar: several dendrites, 1 axon, multiple branches, most common in CNS esp. motor neurons.

Answer 2

Functional Classification:
> sensory: carry information to CNS
- axons are afferent fibers; connect brain/spinal cord to sensory receptors
- somatic sensory neurons: carry information about the outside environment
- visceral sensory neurons: carry information about internal environment

> receptors:
- interoceptors: digestive, respiratory, cardiovascular, urinary, reproductive system, presure, pain, taste
- exteroreceptors: touch, temperature, and pressure, sight, smell, hearing
- proprioreceptors: position of body parts relative to body

> motor neurons:
- axons are efferent fibers
- SNS: somatic motor neurons, innervate skeletal muscles; connect CNS to NMJs
- ANS: viseral motor neurons
> two groups within the ANS, one w/ cell bodies in the CNS and other in the peripheral ganglia
> preganglionic fibers (between CNS to ganglion) and postganglionic fibers (ganglion to effectors)

> interneurons: input sensory information, output motor effects
- excitatory vs inhibitory (release excitatory neurotransmitters vs inhibitory neurotransmitters)

Answer 3

Adapted from Human Anatomy, Martini, et. al. 9th edition