NEUROTRANSMISSION PED1003 EXAM QUESTIONS AND
ANSWERS WITH COMPLETE SOLUTIONS GRADED A++
What is the nervous system?
Complex network of interconnecting neurones
What is a neurone?
Excitable cells which release neurotransmitters
What is neuronal signalling?
Transfer of information along or between neurones
What are the two types of neuronal signalling?
Chemical, Electrical
What is electrical signalling?
Cell body communicates with axon using its electrical impulses (Action potentials).
These impulses cause depolarisation of the terminal and the release of
neurotransmitters
What are the physiological importance of electrical signalling?
Transfer of information
What is the pharmalogical importance of electrical signalling?
Site for drug actions, eg. Anaesthetics and anticonvulsants
Which major ions contribute to membrane potential?
Na+ is impermeable, Cl- is permeable, K+ is permeable, A- is fixed inside
What is an electrochemical gradient?
, -ions diffuse in accordance with combined forces of conc gradient and ionic gradient. If
membrane is permeable to +ve ions, distribution will be uneven as conc gradient
competes with ionic force
Which 2 forces act on ionic flux?
Concentration gradient, Electrical gradient
How does potassium effect membrane potential?
The membrane is partially permeable to k+ ions as they move down the conc gradient,
but are also forced inside by ionic gradient, and transported by atpase pump
How does chlorine effect the membrane potential?
Membrane is partially permeable to cl- ions, which move into the cell down the conc
gradient, but are forced out the cell by ionic gradient
How do ions change the RMP?
Na+ and cl- are concentrated outside the cell, k+ and a- are concentrated inside, so
ionic charge is unequal and inside the cell is more negative (-60mv compared to -90mv)
How do neurones rapidly alter the RMP?
VG ion channels that open at particular voltages
How are action potentials affected by Na+ movement?
VG channels open, Na+ floods in, depolarises cell.
How are action potentials affected by K+ movement?
VG K+ channels open, K+ leaves cell, reducing MP.
Where are action potentials propagated?
Axon hillock.
How are APs propagated?
ANSWERS WITH COMPLETE SOLUTIONS GRADED A++
What is the nervous system?
Complex network of interconnecting neurones
What is a neurone?
Excitable cells which release neurotransmitters
What is neuronal signalling?
Transfer of information along or between neurones
What are the two types of neuronal signalling?
Chemical, Electrical
What is electrical signalling?
Cell body communicates with axon using its electrical impulses (Action potentials).
These impulses cause depolarisation of the terminal and the release of
neurotransmitters
What are the physiological importance of electrical signalling?
Transfer of information
What is the pharmalogical importance of electrical signalling?
Site for drug actions, eg. Anaesthetics and anticonvulsants
Which major ions contribute to membrane potential?
Na+ is impermeable, Cl- is permeable, K+ is permeable, A- is fixed inside
What is an electrochemical gradient?
, -ions diffuse in accordance with combined forces of conc gradient and ionic gradient. If
membrane is permeable to +ve ions, distribution will be uneven as conc gradient
competes with ionic force
Which 2 forces act on ionic flux?
Concentration gradient, Electrical gradient
How does potassium effect membrane potential?
The membrane is partially permeable to k+ ions as they move down the conc gradient,
but are also forced inside by ionic gradient, and transported by atpase pump
How does chlorine effect the membrane potential?
Membrane is partially permeable to cl- ions, which move into the cell down the conc
gradient, but are forced out the cell by ionic gradient
How do ions change the RMP?
Na+ and cl- are concentrated outside the cell, k+ and a- are concentrated inside, so
ionic charge is unequal and inside the cell is more negative (-60mv compared to -90mv)
How do neurones rapidly alter the RMP?
VG ion channels that open at particular voltages
How are action potentials affected by Na+ movement?
VG channels open, Na+ floods in, depolarises cell.
How are action potentials affected by K+ movement?
VG K+ channels open, K+ leaves cell, reducing MP.
Where are action potentials propagated?
Axon hillock.
How are APs propagated?
