1. Autonomic
Nervous System
Dr. Sama-ul-Haque

2. Objectives Define autonomic nervous system.
Describe sympathetic and parasympathetic nervous system.
Enumerate the functions of sympathetic and parasympathetic nervous system.

3. The Autonomic Nervous System
ANS is the subdivision of the peripheral nervous system that regulates body activities that are generally not under conscious control
Visceral motor innervates non-skeletal (non-somatic) muscles
Composed of a special group of neurons serving:
Cardiac muscle (the heart)
Smooth muscle (walls of viscera and blood vessels)
Internal organs
Skin

4. Autonomic system: chains of two motor neurons
Basic anatomical difference between the motor pathways of the voluntary somatic nervous system (to skeletal muscles) and those of the autonomic nervous system
Somatic division:
Cell bodies of motor neurons reside in CNS (brain or spinal cord)
Their axons (as nerves) extend all the way to their skeletal muscles.
Autonomic system: chains of two motor neurons
1st = preganglionic neuron (in brain or cord)
2nd = gangionic neuron (cell body in ganglion outside CNS)

5. Axon of 2nd (ganglionic) neuron extends to the organ it serves
Axon of 1st (preganglionic) neuron leaves CNS to synapse with the 2nd (ganglionic) neuron.
Axon of 2nd (ganglionic) neuron extends to the organ it serves
Diagram contrasts somatic (lower) and autonomic:
autonomic
this dorsal root ganglion is sensory
somatic

6. Divisions of the autonomic nervous system
Parasympathetic division
Sympathetic division
Serve most of the same organs but cause opposing or antagonistic effects
Parasympathetic: routine maintenance
“rest &digest”
Sympathetic: mobilization & increased metabolism “fight, flight or fright”

9. Where they come from T1 to L2 Sympathetic Parasympathetic
Thoracolumbar
T1 to L2
Parasympathetic
Craniosacral

10. Paravertebral Ganglionic chain or Sympathetic Trunk

11. Paravertebral
Ganglionic
chain

12. Spinal Nerve

13. Sympathetic nerve

16. Sympathetic
Nervous
system

17. Parasympathetic
Nervous system

20. Functions of Sympathetic Nervous System
Increased Heart Rate
Increased Blood Pressure
Pupil Dilation
Decreased Urination
Increased Sweating
Bronchial Dilation
Decreased Salivation

21. Functions of Parasympathetic Nervous System
Decreased Heart Rate
Decreased Blood Pressure
Pupil Constriction
Increased Urination
Decreased Sweating
Bronchial Constriction
Increased Salivation

22. Thank You