Flashcards in cells of the neuro system Deck (24)
receive inputs from other neurones and convey graded electrical signals passively to the soma
synthetic and metabolic centre. Contains the nucleus, ribosomes, mitochondria and endoplasmic reticulum
cell body (soma)
site of initiation of the ‘all or none’ action potential?
conducts output signals as action potentials to other neurones (or other cells). Mediates transport of materials between the soma and presynaptic terminal (anterograde direction) and vice versa ?
point of chemical (usually) communication between neurones (or other cells)
when a neurone is depolarising, what electrolyte comes in ?
during depolarisation which electrolyte leaves neurone?
why do passive signals not spread far from their site of origin?
nerve cell membrane is leaky
what can you do to increase passive current spread?
increase axon diameter, adding more myelin sheath
which cells add insulating material (myelin sheath) in the PNS and CNS?
oligodendrocytes in CNS and schwann cells in PNS
difference in conduction between myelinated axons and non myelinated?
much faster in myelinated
action potential jumps from one node of ? to the next
Types of synapse (2)?
In the CNS, what is the transmitter in an excitatory synapse?
what are the major amino acid neurotransmitters in the CNS?
GABA, glutamate and glycine
common neurotransmitters in the inhibitory synapse?
GABA and glycine (GABA exhibit excitement)
what kind of response does glutamate generate?
local, graded, excitatory (depolarizing) response: the excitatory postsynaptic potential (e.p.s.p.)
WHAT KIND OF RESPONSE DOES GABA AND GLYCINE GENERATE?
a local, graded, inhibitory (hyperpolarizing) response: the inhibitory postsynaptic potential (i.p.s.p.)
why do some cells have net excitation and some net inhibition?
many inputs converge upon a neurone to determine its output
what are glycine and glutamate?
where is GABA synthesised?
in the neurones that release it
Enzymes are synthesized in the cell body and are transported to the presynaptic terminal by ?
what mediates synthesis within the cytoplasm of neurotransmitter from precursor substances?