Physiology Lecture (5) PDF

Physiology ANS & Autonomic Ganglia LECTURE (5) DR. El-Sawy 0  Physiology ANS & Autonomic Ganglia...

Physiology ANS & Autonomic Ganglia LECTURE (5) DR. El-Sawy 0  Physiology ANS & Autonomic Ganglia Definition :  The part of nervous system concerned with regulation of involuntary or visceral functions in the body. Divisions of ANS : Sympathetic Parasympathetic “Fight or flight” “Rest and Digest” 1. Prepares body for activity 1. Predominates during rest & sleep.  by ↑ capacity to perform severe ms effort in response to stress. 2. Delay onset of fatigue of contracting 2. Allow for repair and recovery of muscles. contracting muscles. 3. Sympathetic mass stimulation is 3. Parasympathetic mass stimulation useful. may be fatal. 4. Increases energy expenditure of 4. Preserve energy in the body body 5. Catabolic to energy 5. Anabolic energy DR. El-Sawy 1  Physiology ANS & Autonomic Ganglia Course of ANS : Preganglionic neuron Postganglionic neuron Outside CNS Origin Inside CNS (autonomic ganglia) End Autonomic ganglia. At effector organs Type Thin myelinated (type B). Non-myelinated (type C). Colour White Gray No. Few More Chemical Acetylcholine (Ach) Ach or noradrenaline transmitter DR. El-Sawy 2  Physiology ANS & Autonomic Ganglia Definition  Collection of cell bodies of neurons outside CNS ( in PNS ). 1) Relay station : For autonomic pre-ganglionic nerve fibers 2) Distributing center : a. Sympathetic nervous system: Ratio of preganglionic fibers to postganglionic fibers is 1:32 Functions  Generalized effects. b. Parasympathetic nervous system: Ratio of preganglionic fibers to postganglionic fibers is 1:2  Localized effects. Note Adrenal medulla: The only sympathetic effector organ directly innervated by preganglionic nerve fibers. DR. El-Sawy 3  Physiology ANS & Autonomic Ganglia Types of ganglia : Lateral (Para-Vertebral) Collateral (pre-vertebral) Terminal  On both sides of spinal cord  Present mainly in abdomen  Lie close to or at the wall  Interconnected by nerve fibers   Midway () spinal cord & viscera. of effector organs. Site sympathetic chain  Short preganglionic & long  Preganglionic is equal in length  Long preganglionic & short postganglionic fibers. to postganglionic fibers. postganglionic fibers.  According to spinal segment :  Closely related to aorta & its a. 3 cervical : branches and named according Superior – Middle - Inferior to them : Name b. 12 thoracic. 1) Celiac ganglion c. 5 lumbar. 2) Superior mesenteric ganglion d. 5 sacral. 3) Inferior mesenteric ganglion e. 1 coccygeal. 4) Aortico - renal ganglion. For  Sympathetic fibers.  Sympathetic fibers.  All parasympathetic fibers Sympathetic  Short preganglionic & long post ganglionic. Parasympathetic  Long preganglionic & short postganglionic. DR. El-Sawy 4  Physiology ANS & Autonomic Ganglia DR. El-Sawy 5