Organisation of the Sympathetic Nervous System

Sympathetic pre-ganglionic neurons

Short neurons located next to spinal cord.

Sympathetic post-ganglionic neurons

Long neurons that transmit signals to target organs.

Acetylcholine

Neurotransmitter released by pre-ganglionic neurons.

Nicotinic acetylcholine receptors

Receptors on post-ganglionic neurons for acetylcholine.

Noradrenaline

Neurotransmitter released by post-ganglionic neurons.

Adrenoceptors

Receptors that noradrenaline acts upon.

Salivary glands

Sympathetic neurons release acetylcholine here.

Muscarinic acetylcholine receptor

Receptor for acetylcholine in salivary glands.

Noradrenaline vs Adrenaline

• Both are catecholamines and monoamine neurotransmitters

• adrenaline has an extra methyl on the amine group

Paravertebral ganglia

Most sympathetic ganglia near the spinal cord.

Prevertebral ganglia

Ganglia located close to target tissues.

Adrenal Medulla

Produces adrenaline under sympathetic control.

Chromaffin cells

Cells in adrenal medulla that release adrenaline.

ratio of adrenaline to noradrenaline in circulation

4:1 ratio