Autonomic Nervous System

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. 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 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 Sympathetic 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