L3 - Neuronal structure and function Flashcards
What are the basic properties of neurons?
Cell membrane
Nucleus: contains DNA, the genetic blueprint for cell structure and function
Organelles + machinery for translating genetic code for proteins
Metabolic machinery: enables glucose oxidation to provide energy
What are dendrites + what is it specialised for?
network of fine processes from the cell body
specialised for receiving signals
What are synapses?
connection between 2 neurones
What is the axon hillock?
site of action potential generation
What is the axon + what is it specialised for?
elongated neural process
specialised for rapid signal transmission over long distances
What is myelination?
fatty sheath around axons
What is differential permeability?
The neuronal cell membrane allows certain ions to pass through more easily than others, which creates an uneven charge distribution.
This difference is the membrane potential
What is the resting membrane potential of neurones?
-70mV
What is polarisation + what causes it?
Where there is a difference n electrical charge between the inside + outside of the cell
This difference in charge creates a voltage, which is called membrane potential
What are the contributing ions in membrane potential?
Sodium (NA+)
Potassium (K+)
Chloride (Cl-)
Negatively charged proteins (A-)
What is depolatisation?
increase in NA+ permeability making the membrane potential less negative
What is hyperpolarisation?
increase in Cl- permeability makes the membrane potential more negative
What is signal integration?
when a neuron combines multiple incoming signals to determine its overall response
What are the 2 synaptic inputs?
Excitatory Postsynaptic Potentials (EPSPs)
Inhibitory Postsynaptic Potentials (IPSPs)
What do Excitatory Postsynaptic Potentials (EPSPs) do?
they depolarise the neuron, making the. inside of the cell less negative + closer to the threshold for generating an action potential
What do Inhibitory Postsynaptic Potentials (IPSPs) do?
they hyperpolarize the neuron, making the. inside of the cell less negative + closer to the threshold for generating an action potential
What is spatial sumation?
when multiple synaptic inputs from different locations on the neuron’s dendrites + cell body occur simultaneously + their combined effects can add together
if enough EPSPs combine they can bring the neuron to the threshold for firing an action potential
What is temporal summation?
when multiple synaptic inputs occur in rapid succession at the same synapse, their effects can add over time
if these inputs are close enough in time, they can collectively bring the neuron to the threshold
What is the all-or-none phenomenon in regards to action potential?
an action potential is always the same size and does’t decay over distance
what is action potential mediated by?
rapid changes in membrane permeability to Na+ and K+
What are the components of a synapse?
Synaptic vesicles - contains neurotransmitters
postsynaptic receptors - bind neurotransmitters
neurotransmitter reuptake sites - remove neurotransmitters from the synaptic cleft
What is the process for neurotransmitters to be released?
they’re combined near the release ste
stores until required
released into the synaptic cleft in response to action potential
bind to receptors on the postsynaptic membrane
What are the 6 examples of neurotransmitters?
AMINO ACIDS:
Glutamate: excitatory
GABA: inhibitory
MONOAMINES:
Dopamine: excitatory and inhibitory
Noradrenaline: excitatory and inhibitory
Serotonin: excitatory and inhibitory
OTHERS:
Acetylcholine: excitatory and inhibitory
what affects membrane potentials?
Local anesthetics
what affects synthesis?
L-DOPA enhances dopamine synthesis for Parkinson’s treatment
what interacts with receptors
Dopamine receptor antagonists for Sz
what affects reuptake?
SSRIs for depression
