lecture 2 Overview of Human Nervous System

Structure of synapse

• pre-synaptic cleft: before synapse, has message that needs sent

• synaptic cleft: space b/w 2 neurons/nerve cells

• post-synaptic terminal: after synapse, receives message

• synapse: point of connection b/w 2 neurons in pathway

Excitatory

• “yes” send our message

• glutamate: to brain cells (CNS)

• acetycholine: to muscle cells (PNS)

Inhibitory

• “stop” don’t send message

• GABA (gamma aminobutyric acid): tells next neuron in process to stop (CNS and PNS)

Anterograde

• action potentials, neurotransmitters

• forward

Retrograde

• waste products, toxins, viruses

• gets in through permeable shield

• backwards

apoptosis necrosis injury

• death

• road closes

diaschisis

• when neuron doesn’t receive stimulation and will die

Excitation

• excitatory message keeps going

• “feed forward excitation”

Inhibition

• Inhibitory message keeps going

• “feed forward inhibition”

transmission patterns (networks)

• feedforward

• feedback

• lateral

• convergence

• divergence

Excitation

• Feedback: excites neuron EARLIER in circuit

• Feedforward: excites neuron LATER in circuit

Inhibition

• Feedback: inhibits neuron EARLIER in circuit

• feedforward: inhibits neuron LATER in circuit

• lateral: inhibits neuron in adjacent circuit (more common)

• Disinhibition: activates neuron by inhibiting an inhibitory neuron

Lateral Inhibition

picture

Disinhibition

• “stop stop stop”

• stop saying stop

• can go

convergence

• integration of multiple neurons

• facilitates propagation of single signal transmission (increases likelihood of neuronal firing)

  • excitatory and inhibitory

Divergence

• coordination of signal transmission from single neuron to multiple neurons

  • excitatory and inhibitory