Lecture 2: Neurons and Synaptic Transmission Flashcards
3 Levels CNS handles information at
1) Sensory (energy detectors/receptors)
2) Association (processing system)
3) Motor level (motor system)
Efferent
Towards the muscle
Afferent
Towards the CNS
6 Steps of CNS
1) Sensory systems detect energy
2) energy is converted to electrical impulses
3) carried along axons of afferent fibres to CNS
4) processed in CNS
5) carried by efferent fibre to muscle or gland
6) we respond to initial stimuli
What are neurons responsible for
transmission of electrical impulses
What is neuroglia
material which surrounds and insulates neurons
Excitatory synapse
Depolarises postsynaptic membrane
Which transmitter depolarises
glutamine
Inhibitory synapse
inhibitory synapse hyperpolarises postsynaptic membrane
Which transmitter hyperpolarises
GABA
5 Types of Neuroglia
1) ependymal cell
2) astrocyte
3) microglial cell
4) oligodendroglial cell
5) Schwann cell
7 Steps of Electrical Activity in Neurons
1) All chemicals seek equilibrium through diffusion
2) Diffusion affects two important chemicals (sodium and potassium)
3) The neuron is built in a way that produces an electrical difference between the inside and outside of the cell
4) when the neuron collects enough stimulation, the sodium gates open
5) The action potential opens gates in succesive areas of the axon
6) the action potential leaps over obstacles (saltatory conduction)
7) the action potential reaches the end of the axon
2 Ways in which equilibrium is maintained
1) semi-permeability of membrane
2) sodium-potassium pump (pumps out 3 sodium ions for every 2 potassium ions brought in
What does equilibrium result in
in inside of the cell being less positively charged than the outside (polarisation)
Action Potential
Can only occur in axon, happens when cell body receives enough stimulation (all or nothing phenomenon) causes depolarisation
