physiology notes: sympathetic & parasympathetic

PHYSIOLOGY NOTES

SUMMARY OF THE SYMPATHETIC DIVISION

1. Includes motor nuclei from thoracic and lumbar regions of spinal cord

2. It includes two segmentally arranged chains, one on each side of the spinal column, 3 collateral ganglia and 2 adrenal medualle.

3. Preganglionic fibers are short; postganglionic fibers are long.

4. Shows extensive divergence: can control a variety of effectors and produce a coordinated response.

5. All preganglionic neurons release acetylcholine at their synapses with ganglionic neurons; most postganglionic fibers release norepinephrine

6. The effector response depends on the nature of the channels or enzyme activated when norepinephrine or epinephrine binds to alpha or beta receptors.

SUMMARY OF THE PARASYMPATHETIC DIVISION

1. Includes motor nuclei associated with cranial and sacral regions.

2. Postganglionic neurons close to target organs

3. All are cholinergic (nicotinic or muscarinic)