Lecture 01 Introduction to the Nervous System

Functions of the nervous system

What are the key 6 functions of the nervous system? PACMEL - make mindmap

• Lecture 01 Introduction to nervous system

CNS v.s. PNS

CNS = neuron + glia All components of CNS stay within the brain or spinal cord CNS neurons only synapse with neurons. CNS = forebrain + brainstem + cerebellum + spinal cord CNS is in charge of analysis and integration

PNS = neuron and glia PNS neurons interact with the environment/non-neurons e.g.: sensory and motor neuron PNS = Somatic nervous system + Autonomic nervous system Somatic = sensory nerves and ganglia + motor nerves Autonomic = viscera + sympathetic + parasympathetic

Embryonic origins

Order of embryonic development: neurotube becomes CNS 3 vesicle stage prosencephalon (forebrain) Mesencephalon (midbrain) Rhombencephalon (hindbrain) 5 vesicle stage Telencephalon (cerebral hemisphere) Diencephalon (thalamus and hypothalamus) Mesencephalon (midbrain) Metencephalon (pons + cerebellum) Myelencephalon (medulla) Abnormally: Spina Bifida (improper closure)

CNS Embryology (Embed)

Development of the neural axes

Draw the outline of the development of neural axes at the 3 vesicle stage 3 axes in total (cephalic flexure and cervical flexure) cephalic flexure is between mesencephalon and rhombencephalon cervical flexure is between rhombencephalon and SC cervical flexure resolves at the 5 vesicle stage cephalic flexure migrates between diencephalon and mesencephalon Axes of orientation Rostral v.s. caudal Dorsal v.s. ventral

Brain+Flexures+(Slide+1+Of+2) (image/jpeg)

Classification of the neurons

By morphology (how many extensions directly off of the cell body?) Unipolar (body + axon) Pseudo-unipolar (distal axon + body + proximal axon) Bipolar (dendrite + body + axon) Mutipolar (dendrites + body + axon) Functional zones of a neuron Input zone Integrative zone Conducting zone insulation, AP regeneration Transmitting zone Transmitter release, transmitter uptake

Classification of synapses

Presynaptic and postsynaptic membrane Axodendritic synapse Axosomatic synapse Axoaxonic synapse Somosomatic synapse Dendrodendritic synapse

Functional classification Chemical synapse Electrical synapse

Classification by pharmacology

Glutamate - glutamatergic GABA - GABAergic Acetycholine - dopaminergic Dopamine - dopaminergic Glycin - glycerinergic Serotonin - serotonergic Norepinephrine - noradrenergic Histamin - histaminergic What are the qualifications to be a neurotransmitter?  NT must be made by the presynaptic neuron Ca2+ must be required for release of NT Post synaptic membrane must have the receptor to bind with the NT  

Glia cells

Image22 (image/png)

CNS cells Astrocytes (support, BBB, secretion) Oligodendrocytes (myelin sheath) Ependymal cells (barriers between compartments) Microglia cells (immune cells) PNS cells Schwann cells (Myelin formation) Satellite cells (support)