Autonomic Nervous System. Ms. DS Pillay Room 2P24

Transcription

1 Autonomic Nervous System Ms. DS Pillay Room 2P24

2 OVERVIEW OF THE NERVOUS SYSTEM NERVOUS SYSTEM CNS PNS BRAIN SPINAL CORD SOMATIC ANS SYMPATHEIC PARASYMPATHEIC

3 LOCATION OF GANGLIA IN THE ANS Short post-ganglionic fibre Short pre-ganglionic neuron Long post-ganglionic fibre (intra-mural) Long pre-ganglionic fibre

4 PARASYMPATHETIC

5 CRANIOSACRAL OUTFLOW In the CNS Parasympathetic Cranial Nerves III -Oculomotor N VII Facial N IX Glossopharyngeal N X Vagus N Spinal Cord = S2,3,4 cord segments In the PNS Postganglionic neurons in intramural ganglia within visceral wall Therefore... PNS = Craniosacral Outflow

6 PARASYMPATHETIC Pre-ganglionic fibres from - cranial nerves III,VII,IX & X - Sacral segment S2-S4 Parasympathetic ganglia - Ciliary - Pterygopalatine - Submandibular - Otic Fibres from sacral segment form pelvic splanchnic nerves which enters inferior hypogastric plexus

7 CN Nucleus Preganglionic nerve 3 Edinger- Westphal Ganglion Post ganglionic nerve Target organ Oculomotor Ciliary Short ciliary Sphincter pupillae Ciliary muscles 7 Superior Salivatory Chorda tympani Submandibular Lingual Salivary glands: Submandibular Sub-lingual Lingual Labial Buccal Greater petrosal Pterygopalatine Maxillary Lacrimal Nasal Palatine Pharyngeal glands 9 Inferior salivatory nucleus Tympanic branch. Otic ganglion Auriculotempo Parotid gland Lesser petrosal ral nerve, nerve 10 Dorsal vagal Vagus nucleus Minute ganglia in individual organs. individual Thoracic and abdominal viscera

8 SACRAL PARASYMPATHETIC OUTFLOW Origin Anterior primary rami of the S2, 3 and 4 Course Pelvic splanchnic nerves Hypogastric plexus Ganglia In walls of individual viscera Post ganglionic nerves Individual Target Distal transverse colon Descending colon Sigmoid colon Pelvic viscera External genital organs

9 SYMPATHETIC NS The PATHWAY OF THE NEURONS Pre-ganglionic fibres & Postganglionic fibres Para-vertebral ganglia- 3 cervical (superior, middle & inferior),usually 11 thoracic, 4 lumbar & 4 sacral.

10 HYPOTHALAMUS In the CNS Hypothalamus = HQ Spinal Cord = T1 to L2 segments (pre-ganglionic neurons) In the PNS Pair of Sympathetic Chains with ganglia on it, (postganglionic neurons) distributed to ALL VISCERA distributed to SKIN ** distributed to Head and Neck

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12 PARTS OF THE SYMPATHETIC TRUNK Cervical part Receive preganglionic fibres T1- T5 Lies on the pre-vertebral muscles behind the carotid sheath. Three interconnected ganglia respectively known as superior, middle and inferior cervical sympathetic ganglia Post ganglionic fibres distributed with neighboring arteries to head, neck and upper limb Thoracic Receives preganglionic fibres T1- T5 Lies on the necks of the ribs in the upper part of the thorax and the sides of the vertebra in the lower part. Behind pleura Distributed to thoracic visceral

13 PARTS OF THE SYMPATHETIC TRUNK Abdominal T6- T12 Lies on the anterolateral surface of the lumbar vertebrae Right trunk lies behind the inferior vena cava Crosses sacral promontory to become continuous with the pelvic trunk. Distributed to abdominal viscera. The Pelvic Pelvic splanchnic L1-L2 Downwards on the pelvic surface of the sacrum, The two trunks usually unite in front of the coccyx and end in a smallunpaired ganglion (ganglion impar).

14 Autonomic ganglia and plexus Thorax Cardiac and pulmonary Abdomen Celiac, superior mesenteric, inferior mesenteric Pelvic Hypogastric

15 Sympathetic Parasympathetic Origin thoracolumbar Cranio-sacral Ganglia Para-vertebral Peripheral (near target) Neuro transmitters at target Adrenaline/ nor-adrenaline Acetyl-choline Distribution Wide spread Localised Predominant effect Fight and flight response calm body maintenance