Neuronal Function

Question 1

Neuronal specialisation

Answer 1

Excitability of the membrane dentrites - network of fine prices derived from cell body
Synapse- connection between two neurones
Axon - elongated neural process specialised for rapid signal transmission over long distances

Question 2

Membrane potentials

Answer 2

Neuronal cell membrane is differently permeable to intracellular and extracellular chemical constituents
Osome ions can pass through the membrane easily other pass through but with diffucty other can’t pass through at all
As a result of this differential permeability tomions there is an uneven distribution of charg3 across the membrane
This difference is the membrane potential resting is -70mv

Question 3

What are the main ions contributing to the membrane potential

Answer 3

Positively charged sodium (na+) and potassium (k+) and negative,y charged chloride (cl-) and proteins (A-)

Question 4

Changes in membrane potential

Answer 4

Increasing permeability to sodium (na+) causes membrane to become less negative (depolarisation)
Increasing the permeability to chloride (cl-) causes the membrane to become more negative

Question 5

The action potential

Answer 5

An electrical spike caused by reversal of membrane polarity transmits information along the axon
Rapid transmission over long distances must not decay over long distances mediated by rapid changes in membrane permeability tomions
All or none phenomenal an action potential is always the same size does not decay over distance an action potential is the same size when. It reaches the terminal as it was when it left the axon hillock

Question 6

Neurotransmitter

Answer 6

Synthesised in the neurones close to the site of release
Stored on the terminal until required for release
Re,eased into synaptic cleft in response to an action potential
Binds to receptors in postsynaptic. Membrane
Causes changes in membrane potential
Excitiry receptors cause depolarisation
Inhibitory cause hyperpolarisation

Question 7

Examples of some neurotransmitter

Answer 7

Glutamate gaba dopamine noradrenaline serotonin acetylcholine

Question 8

Receptor pharmacology

Answer 8

Neurotransmitter binds to receptor and evokes excitation or inhibition
Agonist binds to receptor and evokes any response as the native transmitter
Antagonist to receptor and does not evoke any response prevents the native transmitter or any agonist from binding to the receptor

Question 9

Examples of drugs acting by different mechanisms

Answer 9

Drugs affecting membrane potentials - local anaesthetic
Drugs affecting synthesis - L dopa enhances dopamine synthesis in treatment of Parkinson’s disease
Drugs interacting with receptors dopamine receptors antagonists used in treatment of schizophrenia
Drugs affecting reuptake serotonin reuptake inhibitors used in treatment of depression drugs affecting breakdown - serotonin breakdown inhibitors used in treatment of depression