1. Lecture 2 Functions of ANS

2. Functions of ANS are carried out by Sympathetic division Parasympathetic division [=Thoraco-Lumbar outflow] [=Cranio-Sacral outflow] Dr.Gehan El-Salamony

3. Both divisions of ANS antagonize each other in most of the body organs. (one speeds up an organ, while the other slows down the same organ) e.g. sympathetic NS increases heart rate while parasympathetic NS decreases heart rate. At rest, the body is regulated by the parasympathetic NS. In stress conditions, the sympathetic NS dominates. Dr.Gehan El-Salamony

4. Sympathetic NS  Sympathetic division of the ANS prepares the body to deal with stress  It is called the fight and flight division Dr.Gehan El-Salamony

5. Sympathetic NS Dr.Gehan El-Salamony Origin of the Sympathetic NS = Thoraco-lumber outflow 1)LHC of all thoracic segments. 2)LHC of upper 3 or 4 lumber segments.

6. Parasympathetic NS  Parasympathetic NS allows the body to recover from stress  It is called the rest and sleep division of the ANS Dr.Gehan El-Salamony

7. Parasympathetic NS Dr.Gehan El-Salamony Origin of parasympathetic NS = Cranio-sacral outflow 1) Cranial nerves III, VII, IX & X 2) LHC of S2, 3 & 4.

8. Short Short preganglionic Long Long postganglionic Ganglia close to spinal cord Long Long preganglionic Short Short postganglionic Ganglia on/in target organ

9. Sympathetic Ganglia Sympathetic Ganglia (long post-ganglionic nerve fibers) 1. Lateral ganglia. 2. Collateral ganglia. Parasympathetic Ganglia (short post-ganglionic nerve fibers) * Terminal ganglia. Dr.Gehan El-Salamony

11. Functions of Sympathetic & Parasympathetic Nervous System

12. Sympathetic NS It is characterized by: emergency and stress fear, fight and flight reactions  It discharges during emergency and stress (fear, fight and flight reactions). one unit generalized action  It acts as one unit (generalized action). WHY ?? to prepare the body to face stress Dr.Gehan El-Salamony

13. Sympathetic Nervous System prepares the body through the following effects :

14. 1-Heart: 1- Heart: increase cardiac activity (to blood supply to active tissues) 2- Blood vessels: 2- Blood vessels: Vasoconstriction [ Vasodilation of Sk.Muscle blood vessels] 3- Lungs: 3- Lungs: bronchodilation (to increase ventilation & O 2 supply ) 4-Metabolism: 4- Metabolism: increase blood glucose It has catabolicaction (It has catabolic action) 5-Sweat glands: 5- Sweat glands: profuse secretion to control body temperature (to control body temperature) Dr.Gehan El-Salamony

15. 6-Digestive & urinary system activities 6- Digestive & urinary system activities: It delays evacuation of visceral content (causes wall relaxation + sphincter contraction) (inhibits defecation & micturation) Dr.Gehan El-Salamony

16. Other effects of sympathetic activation  Eye:  Eye: dilatation of the pupil + widening of the palpebral fissure + exophthalmos. (enables the subject to assess his surrounding)  Adrenal medulla:  Adrenal medulla: secretion of adrenaline & noradrenalin (augments sympathetic activity) Dr.Gehan El-Salamony

18. Question What will be the result of cervical symp. chain injury? Affect symp. Supply of the face Eye Skin Dr.Gehan El-Salamony

19. Horner’s syndrome Caused by injury of cervical sympathetic chain on one side. Symptoms: 1-Ptosis. 2-Miosis. 3-Enophthalmos. 4-Anhydrosis. 5-Redness of skin (V.D.) On the same side of injury

20. Parasympathetic NS It is characterized by rest and sleep  It discharges during rest and sleep localized  Its action is localized anabolic conserve body stores  It has anabolic action ( conserve body stores ). secreto-motor.  It increases gastrointestinal secretion & motility i.e. secreto-motor. Dr.Gehan El-Salamony

22. 3 rd cranial nerve (III n. / Occulomotor nerve): Eye: 1-Pupil constriction (Miosis). 2-Accomodation to near vision 7 th (VII n. /Facial nerve) & 9 th ( IX n./ Glossopharyngeal nerve): Salivary glands: Increases secretion (watery saliva + large volume). 10 th Cranial nerve (X n./ Vagus nerve): Viscera in the thorax & abdomen Heart, lungs, GIT Sacral division (= Pelvic nerve): Urinary bladder & Rectum: Contraction of wall and Relaxation of sphincter micturation & defecation External genitalia: Vasodilatation of the blood vessels erection Dr.Gehan El-Salamony

23. ParasympatheticSympatheticEffector ConstrictionDilatationPupil decreases heart rateIncreases heart rateHeart ConstrictionDilatationBronchi Stimulates secretion & movement Inhibits secretion & movement GIT Contraction of walls & relaxation of sphincter Relaxation of walls & contraction of sphincter Urinary bladder & Rectum ErectionEjaculationGenital organs ---StimulationAdrenal medulla ---Sweat secretionSweat glands ---ConstrictionSystemic arterioles ---DilatationSkeletal muscle arterioles

24. Vagal stimulation causes: 1- Heart decreases heart rate. (It has no direct effect on ventricles) 2- Lungs bronchoconstriction. 3- GIT increases secretion & motility. Dr.Gehan El-Salamony

25. Question Compare between the 2 divisions of ANS regarding:  Origin  Relay in ganglia  Effect of stimulation  Chemical transmission Dr.Gehan El-Salamony