Flashcards in 2.1 Neurones Deck (72):
What do glia do?
Support, nourish and insulate neurones
Also remove waste
Name 3 types of glial cells
What do astrocytes do? (4 points)
Provide structural support to neurones
Helps form blood brain barrier
Why do neurones need astrocytes to provide them with energy?
Neurones do not store or produce glycogen
Astrocytes can store glycogen
What kind of molecules do astrocytes supply neurones with for the energy purposes?
What do astrocytes use to transport energy molecules to neurones?
Glucose lactate shuttle
What role do astrocytes play in terms of neurotransmitters?
Uptake transports to keep extracellular NT conc. low
Why is it important to remove glutamate from the synaptic cleft and terminate the response after a while?
Too much glutamate can be toxic to neurones
What is the buffer function of astrocytes and why is it needed?
Astrocytes take up excess K+
High levels of neuronal activity can lead to increased K+ conc. in brain ECF
What do oligodendrocytes do?
Myelinate axos in the CNS
What are the cells that are responsible for myelination in the CNS and PNS?
CNS - oligodendrocytes
PNS - Schwann Cells
What is the difference in myelination between Schwann cells and oligodendrocytes?
Oligodendrocytes - wrap around multiple neurones
Schwann Cells - wrap around a single neuron
What is the function of microglia?
Part of immune system in brain
How do microglia respond to foreign material?
Recognise --> activation --> Phagocytosis
What kind of cell are microglia?
Antigen presenting cells
How do brain capillaries differ from other capillaries?
Tight junction between endothelial cells
What surrounds brain capillaries?
End feet of astrocytes
What is the function of the blood brain barrier?
Limits diffusion of substances
From blood to Brain ECF
How do substances get past the BBB?
Why is it important that the CNS is immune privileged?
Because the skull is rigid
Inflammation would cause an increased ICP
What are the four main sections in a typical neuron?
What must happen in a presynaptic neuron for neurotransmitter to be released?
Voltage gated calcium channels open
Ca2+ floods in
Name the three chemical classes of neurotransmitters in the CNS?
Name the major excitartory neurotransmitter
What kind of neurotransmitter is glutamate?
Excitatory amino acid
Name two inhibitory amino acid neurotransmitters
What are the two types of glutamate receptors?
What are the two ionotropic glutamate receptors we need to know?
What type of protein is an ionotropic glutamate receptor?
What do ionotropic glutamate receptors let through?
Sodium and potassium ions
What does the activation of ionotropic glutamate receptors lead to?
What kind of protein is a metabotropic glutamate receptor?
What excitatory neurotransmitters do to the postsynaptic cell and how do they achieve this?
Act on ligand gated ion channels
What kind of depolarisation do excitatory neurotransmitters cause and what can this lead to?
Excitatory postsynaptic potential (EPSP)
What are NMDA receptors permeable to?
What are AMPA receptors permeable to?
In what do process do glutamate receptors play a role in?
Learning and memory
What is long term potentiation?
Persistent strengthening of synapses based on recent patters of activity
What step is important for induction of Long term potentiation and how is this achieved?
Ca2+ entry through NMDA receptors
Strong, high frequency stimulation
What can happen if too much calcium enters through NMDA receptors?
What is the main inhibitory transmitter in the brain?
What are the two inhibitory neurotransmitters in the brain?
What protein forms part of both GABA and glycine receptors?
Integral Cl- channels
What is the effect of opening the Cl- channels of GABA and glycine receptors?
What kind of depolarisation does the activation of GABA and glycine receptors cause?
Inhibitory post synaptic potential
What is the effect of inhibitory post synaptic potentials (IPSP)?
Decreased action potential firing
Besides GABA, what else can bind to GABA receptors?
What kind of action do barbituates and benzodiazepines have?
What are barbituates sometime used for?
What are benzodiazepines used for?
What do inhibitory interneurones in the spinal cord released?
Give an example of when glycine is released in a reflex? Go through all of the steps in order to elicit this
Tap patella tendon
Detected by spindle
Afferents --> spinal cord
Efferents --> Quadriceps motor
Interneurones release glycine onto reciprocal muscles
What is the neurotransmitter at neuromuscular junctions?
What does acetylcholine bind to in the brain and what is (predominantly) the effect?
From where do the cholinergic pathways in the brain arise from?
What are the cholinergic pathways of the brain involved in?
Learning and memory
What is degeneration of the cholinergic neurones in the nucleus basalis assocaited with?
What is the degeneration of dopaminergic pathways associated with?
How can Parkinson's be treated?
Besides Parkinson's, what other condition is associated with dopamine dysfunction?
What is though to be the problem in Schizophrenia?
Too much dopamine release
Where do anti-psychotics act?
Dopamine (D2) receptor antagonists
What do you also give to someone who is already receiving levodopa?
Why do you give someone receiving levodopa, carbidopa as well?
So L-DOPA (levodopa) isn't converted to dopamine in the peripheries and is transported across the BBB
dopamine cannot pass through BBB
What is levodopa also known as?
What does noradrenaline act upon in the brain?
GPCR Alpha and beta adrenoceptors
Where do noradrengergic pathways arise from in the brain?
When does the activity of noradrenergic neurones in the brain increase?
During behavioural arousal
What do amphetamines do and how do they achieve this?
Increases the release of NA and dopamine
What is a deficiency of NA in the brain associated with?
What are the functions of the serotonergic pathways in the CNS?