Flashcards in Introduction to neurones, nerve conduction and synaptic transmission Deck (48)
What is the purpose of a dendrite?
To receive inputs from other neurones and convey graded electrical signals passively to the soma
What is the purpose of the soma?
It is the synthetic and metabolic centre
Contains the nucleus, ribosomes, mitochondria and ER
It integrates incoming electrical signals that are conducted passively to the axon hillock
What is the axon hillock?
Site of initiation of the "all or nothing" action potential
What is the function of the axon?
Conducts output signals as action potentials to the presynaptic terminal
Mediates transport of materials between the soma and presynaptic terminal and vice versa by slow and fast axonal transport
What is the function of the synapse?
Point of chemical communication between neurones
What viruses will exploit retrograde transport to infect neurones?
What are the different types of neurones?
Where can unipolar neurones be found?
Peripheral autonomic system
Where can pseudounipolar neurones be found?
Dorsal root ganglion
Where can bipolar neurones be found?
Where can multipolar neurones be found?
Lower motor system
What is the resting potential for a neurone?
What is the threshold for a neurone?
What channels allow for the upstroke and downstroke of the action potential in neurones?
Upstroke = Na+
Downstroke = K+
Why do passive signals in neurones not spread far from their site of origin?
Current loss across the membrane accompanied by a reduced change in potential
What are strategies utilised to increase passive current speed and therefore action potential velocity?
Decreased axial resistance of the axoplasm via increased axon diameter
Increased membrane resistance - addition of myelin provided by schwann cells in PNS and oligodendrocytes in CNS
What is saltatory conduction?
Action potential jumping from one node of ranvier to the next
What are examples of demyelinating disorders?
What separates the pre and post synaptic membranes?
What holds the pre and post synaptic membranes together?
A matrix of fibrous extracellular protein within the cleft
Where are the neurotransmitters stored in the neurone?
Vesicles within the presynaptic terminal
What are the different types of synapses?
What is the most common type of synapse?
What is the most common neurotransmitter of excitatory synapses in the CNS?
What will glutamate activate?
Post synaptic, cation selective, inotropic glutamate receptors resulting in a depolarisation; excitatory postsynaptic potential
What are the major amino acid neurotransmitters in the CNS?
What is the most common neurotransmitter of inhibitory synapses in the CNS?
GABA or glycine
What will GABA/glycine activate?
Postsynaptic, anion selective, inotropic, GABA or glycine receptors generating a local, graded hyperpolarizaing post synaptic potential
What is spatial summation?
Many inputs converge upon a neurone to determine its output