Neuroanatomy + Physiology Flashcards
Function of microglia?
Like macrophages- immune monitoring and antigen presentation
How can AP conduction be increased?
Increase axon diameter
Myelination
Neurotransmitter at an excitatory synapse and what does it activate?
Glutamate
Na receptors- depolarisation
EPSP- excitatory postsynaptic potential
Neurotransmitter at an inhibitory synapse and what does it activate?
GABA or glycine
Cl receptors- hyperpolarisation
IPSP- inhibitory postsynaptic potential
What is spatial synaptic summation?
Multiple simultaneous inputs
What is temporal synaptic summation?
Repeated inputs building up over time
Adaptation rate of a sensory unit?
Change firing in response to change in intensity, or continuous signal
Conduction velocity of a sensory unit?
Differ in diameter, extent of myelination etc.
What is contrast enhancement?
Differences in activity of adjacent neurons are amplified
What is lateral inhibition?
An active neuron inhibits its neighbours
What is the difference between an ionotropic and metabotropic receptor?
Ionotropic- direct channel that opens/closes- fast transmission
Metabotropic- linked to G-protein- slow transmission
What effect does glutamate have on ionotropic receptors?
Excitatory
depolarisation
What effect does GABA have on ionotropic receptors?
Inhibitory (hyperpolarisation)
What are Type IIb/x fibres also known as?
Fast fatiguing
What are Type IIa fibres also known as?
Fatigue resistant
What are Type I fibres also known as?
Slow
What is the function of the superior olive in hearing?
Commutes sound arrival at 2 ears- aids sound location
What do the semicircular canals of the ear detect?
Head movements
What do the otolith organs of the ear detect?
Linear acceleration
Function of the inverse myotatic reflex?
Proprioceptive feedback to execute fine motor tasks
What is the function of reciprocal inhibition?
Antagonise flexors when extensors contract or viceversa
How does referred pain occur?
Several sympathetic afferents carrying visceral pain enter same spinothalamic neurones
Brain interprets info arising from viscera as coming from different area of SKIN
What is a Lacunar Infarct (LACI/LACS)?
Small infarcts in deep brain/brainstem
Symptoms of Lacunar Infarct (LACI/LACS)?
A pure motor or pure sensory stroke or an ataxic hemiparesis
Synapse formed between motor neurones and muscle?
Motor end plate
