2. • Brings about fine changes (with endocrine
system) necessary for optimal internal
environment
• Consists of
– Visceral RECEPTORS (chemo, baro, osmo)
– Afferents to CNS for integration
– Efferents; pre ganglionic, ganglia, post ganglionic
fibers
– Visceral Effectors
3. DIVISIONS
• TWO
• Depending upon the
– Structure
– Function
– Neurotransmitters
• SYMPATHETIC
• PARA SYMPATHETIC
4. SYMPATHETIC
• Larger, widely distributed (1:10)
• Prepares body for Emergency
– Inc heart rate
– Constriction of B.Vs of GIT and Skin
– Dilatation of B.Vs of Sk. M
– More blood to Heart, Brain & Sk. M
– Dilates Pupil
– Sphincters closed
– Piloerection
– Sweating
5. SYMPATHETIC OUTFLOW
• Cell bodies in lat. Horn T1-L2/3
• Ant root sp. N
• White ramus communicantes
• Sympathetic Trunk; Para vertebral gutters, ganglionated
chain (C3, T11/12, L4-5, S4-5)
• Ganglion Impar
• Thoracic spinal nerves via grey ramus communicantes,
for B.Vs of skin, hair and M.
• Ascend / Descend cervical and lumbar Sp. N
• Pass ganglia without synapse Splanchnic Nerves
6.
7. SPLANCHNIC NERVES
• Greater splanchnic nerve (5-9 T segments)
• Lesser splanchnic nerve (10,11 T segments)
• Least splanchnic nerves (12 T)
• Greater and lesser in Celiac Plexus
• Least in Renal Plexus
• Some fibers (Pre ganglionic) reach Adrenal Medulla
• Cells act as modified post ganglionic secrete
Epinephrine and NorEpinephrine
8.
9. PARA SYMPATHETIC OUTFLOW
• Cranio Sacral
• Cranial- 3rd
, 7th
, 9th
& 10th
Cranial Nerve Nuclei
• 3rd
- Edinger Westphal N
• 7th
- Sup. Salivatory & Lacrimatory N
• 9th
- Inf. Salivatory N
• 10th
- dorsal Vagal N
• Sacral; lat column S2-4
• Leave sp. Cord Pelvic Splanchnic Nerve
10. • Ganglia located Peripherally (close to viscera)
• For cranial Cilliary, Pterygopalatine,
Submandibular and Otic ganglia
11. NEUROTRANSMITTERS
• At termination of pre ganglionic fibers of both
Sympathetic and Para Sympathetic is ACETYLCHOLINE
• Receptors – Cholinergic/ Muscarinic
• At termination of Post Ganglionic Para Symp –Ach
• At termination of MOST Post ganglionic Symp-
Norepinephrine
• Receptors – Adrenergic; alpha/ Beta
• At some Post Gang. Of sweat G, B.V in Sk.M - ACh