1

3

2

4

4

2

1

3

the nerve impulse

the refractory period

the threshold period

the stationary phase

the size of the action potential does not change

a certain level of stimulus is required to generate an action potential

only one impulse is conducted at a time

the membrane becomes repolarised quickly after an action potential passes

4,3,2,1

3,2,4,1

1,2,3,4

2,1,4,3

The variable change in the amplitude of the potential based on the strength of the stimulus

The consistent strength of the membrane potential regardless of the stimulus intensity

The ability of a graded potential to propagate over long distances without diminishing

An enzyme that breaks down neuronal proteins in the synaptic cleft to stop signal transmission

A type of hormone released by endocrine glands that travels through the bloodstream to target organs

A chemical messenger released by neurons that transmits signals to other neurons or cells across a synapse

Because K⁺ ions are more abundant outside the cell than inside

Because the membrane is more permeable to K⁺ than to Na⁺ at rest

Because Na⁺ channels are constantly open, allowing Na⁺ to flow out

Low Na⁺ and high K⁺ in the ECF; high Na⁺ and low K⁺ in the ICF

Equal concentrations of Na⁺ and K⁺ in both the ECF and ICF

High Na⁺ and low K⁺ in the ECF; low Na⁺ and high K⁺ in the ICF

Because it measures the chemical gradient between the cell and its environment

Because it describes the movement of ions inside the nucleus.

Because it refers to the difference in electric potential across the cell membrane