The document summarizes the development of the autonomic nervous system (ANS) which has two main divisions - the sympathetic and parasympathetic nervous systems. It describes the migration of neural crest cells to form the sympathetic ganglia along the spinal cord and around the aorta. It also discusses the formation of preganglionic and postganglionic fibers in both the sympathetic and parasympathetic systems. Additionally, it provides an overview of the development of the adrenal cortex and medulla from mesodermal and ectodermal tissues, respectively.

1. Development Of
ANS

2. Divisions
• 1)Sympathetic(Thoracolumbar)
• 2)Parasympathetic(Craniosacral)

3. Sympathetic NS
• Migration of NCC in thoracic region around the spinal
cord immediately behind the dorsal aortae.
• There they are present bilaterally in the form of
segmentally arranged ganglia connected to each other by
longitudinal nerve fibres.

4. Sympathetic Trunks
• They constitute sympathetic trunks one present on each
side of vertebral column
• These trunks get fused in the cervical region hence
obscuring this arrangement

5. Formation Of Sym.Ganglia
• PREAORTIC GANGLIA: Some neuroblasts migrate
around the aorta
• 1)Aortic
• 2)Mesenteric
• OTHER NEUROBLASTS: migrate towards lungs, heart
and GIT

6. PREGANGLIONIC
FIBRES(Myelinated)
• Fibres from visceroefferent column( inter.horn) penetrate
the symp.ganglia of trunk
• Some of them synapse there others don’t and they pass to
preaortic or collateral ganglia
• WHITE RAMUS COMMUNICANS: Nerve fibres
passing from spinal nerve to the symp.ganglia
• Present at T1-L2/L3 level

7. POSTGANGLIONIC
FIBRES(Unmyelinated)
• Fibres of neurons in symp.ganglia either pass to sym
ganglia in trunk at different levels or pass to lungs,heart
and GIT
• GREY RAMUS COMMUNICANS: Pass from ganglia to
spinal nerves
• Present at all levels

8. PARASYMPATHETIC NS
• PREGANGLIONIC FIBRES: From brainstem and sacral
segments
• Pass via CNIII, VII, IX and X to their respective Ganglia
• POSTGANGLIONIC FIBRES: From those ganglia to
their sites of innervation

9. Suprarenal Glands
• 2 parts
• Adrenal cortex: Mesodermal
• Adrenal medulla: Ectodermal

10. ADRENAL CORTEX
• Mesothelial cells b/w root of mesentery and developing
gonad proliferate and penetrate the underlying
mesenchyme to form a large acidophilic organ
“Fetal/Primitive Cortex”
• After birth,it regresses. Just a marginal part persists as
Reticular layer

11. ADRENAL CORTEX
• 2nd wave of mesothelial cells(smaller than 1st ones)
surround the fetal cortex
• Adrenal cortex fully develops at puberty

12. ADRENAL MEDULLA
• NCC invade medial aspect of fetal cortex and arrange in
the form of clusters or cords
• Form chromaffin cells(Called so because they retain
yellow-brown stain with chrome salts)
• In embryo , they are widely scattered but in adult form
they are present only in the medullary region