Neurones and synapses

Question 1

What is a neurone

Answer 1

A specialised cell capable of transmitting information in the form of nerve impulses

Question 2

Functions of the refractory period

Answer 2

1. Ensures a one way movement of action potentials- repolarisation must occur before a further action potential develops
2. Limits the number of action potential that can be fired and ensures each action potential is a discrete entry

Question 3

Factors that affect the speed of a neuron

Answer 3

-Myelination of the axon-
depolarisation occurs at the nodes of ranvier/ no depolarisation under the myelin sheath
-local circuits pass from one node which is depolarised causing depolarisation at the next node/ impulse jumps from one node to the next
2. Diameter of the axon- the thicker the axon, the faster the impulse- proportionally less ion leakage of ions in axons with a larger diameter- if there is too much ion leakage, it makes it very difficult to maintain the potential gradient, required to form resting and action potentials
3. Temperature- affects the speed as it affects the rate at which ions can diffuse across the membrane

Question 4

What are synapses

Answer 4

Junctions between the axon of one neurone and the dendrite of an adjacent neurone