Drugs and disease

Ion channel definition?

A transmembrane protein that forms a pore allowing specific ions to cross the membrane in response to stimuli (voltage, ligand, or mechanical force).

What are ligand-gated channels?

Open or closes when a neurotransmitter binds to them, allowing rapid ion flow

What are voltage-gated channels?

Opens in response to changes in membrane potential, essential in nerve signalling.

What are mechanically-gated channels?

Opens in response to physical deformation of cells, like pressure, stretch or touch (skin)

Resting potential definition?

The difference between the inside of a neuron and the outside of a neuron is called the resting potential (around 70mV). Inside a neuron is negatively charged compared to the outside.

What is the ion gradient?

High concentration of potassium ions (k+) inside the cell and sodium ions (Na+) outside the cell

What is the sodium - potassium pump?

This active transport mechanism maintains the gradient by pumping 3 Na+ ions out and 2 K+ ions in.

Esxplain what nAChR is?

It is a Na2+ channel:

Acetylcholine binds, Na+ channel opens = depolarisation