PLC-beta

PKA

cAMP

G proteins

Ca⁺⁺

C

A beta

B

A alpha

A gamma

At the post-ganglionic synapse

In the CNS

At the ganglion

At the pre-ganglionic synapse

In the pre-synaptic terminals

Beta adrenaline

Only nicotinic ACh

ACh or NA

Only muscarinic ACh

Only ACh

C

A beta

B

A alpha

A gamma

A reduction in the number of 2nd messengers

A reduction in the number of ligand molecules

A reduction in the number of GTP molecules

A reduction in the number of only the β-γ dimer of the G protein

A reduction in the number of GPCRs

Involve binding to ion channels to speed up intracellular responses

Involve binding to membrane receptor proteins that act on ion channels

Involve the use of chaperone proteins to speed up intracellular responses

Involve binding to membrane receptor proteins to speed up intracellular responses

Involve the use of G proteinsto speed up intracellular responses

The time the stimulus is applied for

The time between the initial stimulus and the beginning of the twitch

The total duration of the twitch

The time between the initial stimulus and the muscle returning to passive force levels

The time from the onset of the twitch to the peak of the response

serve as a storage site for Ca²⁺.

 connect the sarcomeres end-to-end.

provide a means of rapidly transmitting the action potential from the surface into the central portions of the muscle fibre.

refill the sarcoplasmic reticulum with Ca²⁺ after it has been released.