Unit 1, Module 1 - Nerves Flashcards
What do transducers do?
Each type is adapted to detect changes in a particular form of energy - e.g. light levels, pressure.
They convert the stimulus energy into a form of electrical energy - a nerve impulse.
What are sensory receptors?
Specialised cells that cab detect changes in our surroundings.
Energy transducers.
How are the channel proteins in neurones specialised?
They are specific either to sodium of potassium ions.
They have a gate that can open or close the channel.
When open, the permeability of the membrane to that particular ions is increased; when closed the permeability is reduced.
They are usually closed.
Other than channel proteins what do nerve cell membranes also contain?
Carrier proteins that actively transport sodium ions out of the cell and potassium ions into the cell - sodium/potassium ion pumps.
How many sodium and potassium ions are transported across membranes by the sodium/potassium pumps?
Three sodium ions are pumped out of the cell.
Two potassium ions are pumped into the cell.
What are some of the different types of neurone?
Sensory neurones that carry the action potential from a sensory receptor to the CNS.
Motor neurones that carry an action potential from the CNS to an effector.
Relay neurones that connect sensory and motor neurones.
