Lecture 1: Comparative Anatomy of Nervous Systems

Somatosensory (SS)

PNS afferent neuron sensing skin or skeletal muscle

Viscerosensory (VS)

ANS afferent neuron sensing organ or gland

Somatomotor (SM)

CNS efferent neuron that stimulates skeletal muscle

Branchiomotor (BM)

CNS efferent neuron that stimulates skeletal muscle also termed special visceral efferent (SVE) neuron

Visceromotor (VM)

ANS efferent neuron that stimulates organ or gland also termed general visceral efferent (GVE) neuron (= neuron in CNS that forms preganglionic fibre of the ANS)

Ganglionic Neuron (GN)

ANS efferent neuron that stimulates organ or gland collectively form autonomic ganglia (= neuron in PNS that forms postganglionic fibre of the ANS)

PNS origin in vertebrates

Neural Crest that migrate out from the dorsal neural tube

PNS origin in invertebrates

In the ectoderm - independent of CNS

Origin of motor neuron in invertebrates

motor neuron in the dorsal part of nervous system

Origin of motor neuron in vertebrates

ventral part of the nervous system

Origin on Somato-motor in vertebrates

pMN region

Origin of Brachio-motor neurones in vertebrates

Vp3 region

Origin of Branchio-motor neurones in invertebrates

invertebrates don’t have Branchio-motor neurones :P

Where are Viscero-motor neurones generated in vertebrates 

In the Vp3 region 

Where are ganglionic neurones generated in vertebrates

In the Neural Crest

In which regions are the motor neurones found in invertebrates

Dorsal region

In which region are motor neurones found in vertebrates

Ventral region

In which region is the nervous system found in vertebrates

Dorsal region

In which regions is the nervous system found in invertebrates

Ventral region