Nerve cell signalling

Question 1

Nerve cells generate electrical signals

what is this calle?

Answer 1

Nerve cell signals are generated against a background potential difference - Resting Membrane Potential

Question 2

Resting Membrane Potential

what ios the potential dofference between?

Answer 2

The Resting Membrane Potential (RMP) is a potential difference between the inside and outside of the membrane

Question 3

Important principles

where is K+ higher?
what is cell membrane permeable to? effect of this?

what does size of RMP depend on?

Answer 3

The [ K+ ] is higher inside cells than outside.
Cell membranes are permeable to K+.
Hence K+ diffuses out of the cells . .
. . leaving excess negative charge inside.
This is the “Resting Membrane Potential”
** The size of the RMP depends on the size of the concentration gradient for K+ **

Question 4

The potential difference is proportional to the concentration difference - how to increase? (4)

Answer 4

Can be increased by:
 Kidney disease 
 Major soft tissue damage
 Medication error
 American justice

Question 5

How do Nerve cells transmit information along their axons?

Answer 5

AP

Question 6

Important principles of AP

when does it occur? why? what restores normal potential?

does conc grad change?

Answer 6

Action potentials occur when the membrane becomes transiently permeable to Na+.
Diffusion of Na+ ions into the cell makes the inside of the membrane positive.
Diffusion of extra K+ ions out of the cell restores the normal negative potential.

** Only miniscule numbers of ions are involved, so the concentration gradients DON’T change **

Question 7

How is the gradient maintained?

Answer 7

Resting Membrane Potential

Question 8

How does Nerve cells transmit information to other nerve cells?

Answer 8

Synaptic Transmission

Question 9

Important principles of synapse transmission

what are signals at chemical synapses carried by?
what releases these?

changes in post synpatic membrane depends on?

Answer 9

Signals at chemical synapses are carried by signalling molecules released by depolarisation of the synaptic bouton.

These “neurotransmitters” bind to specific receptor molecules which trigger changes in the post-synaptic cell.

** The type of change depends on the nature of the receptor **

There are many different neurotransmitters.
Each has many types of receptor.
Different neural pathways use different combinations of neurotransmitter and receptor

** Drugs can be designed to target specific types of synapse, allowing selective effects on different pathways **