Cellular structure of nervous system Flashcards
What is the speed of transmission at the axon hillock
1000 um/msec
What is an electrical synapse
Gap junction - couples electrical activity of two cells by allowing bidirectional ion flow. Useful when you want many cells to do the same thing at the same time
What is a chemical synapse
A normal synapse with presynaptic neurotransmitters and postsynaptic receptors
0.3-0.5 msec delay
Unidirectional
Possible to be hyperpolarising and depolarising
What feature do dentrites have that can help modulate synapse amplitude
Spines on the dendrites are dynamic and are controlled to adjust the amplitude of the synapse
What is the importance of dendrite complexity
Shape of dendritic tree affects function; more distal dendites have a lower efficacy than ones closer to the soma (body) of the neuron. Coincidence detectors (ie signals detected from both ears at once)
What are the effects of demylination
slowing down or even stopping synaptic transmission
What is the name of the mode of conduction down the axon of a neuron called
Saltatory conduction - jumping from one node of Ranvier to the next
What is the difference between white and grey matter
white matter is myelinated
grey matter is not
What is the effect of neural layering in the brain
layering allows for compartmentalisation of modules of the brain therefore is a better spacial distribution
What are some layering diseases
Double cortex syndrome
X-linked lishencephaly (no bumps on brain)
heterotropias
What are the types of neurons
projection local motor sensory presynaptic postganglionic
In which cortical layer do projection neurons live
5
How many cortical layers are there
6
In embryonic development how does the PNS develop
from the neural crest - exiting through the dorsal tube
Describe how different cell types are determined in the development of the nervous system
the DV (dorsal ventral) position
Cells arise from the inner ventricular space and then migrate
