PSIO 121 5th Edition Lecture 32 Outline of Last Lecture AUTONOMIC NERVOUS SYSTEM SYMPATHETIC DIVISION Outline of Current Lecture I AUTONOMIC NERVOUS SYSTEM PARASYMPATHETIC DIVISION II Cranial Nerves III PSNS IV Syncope Current Lecture 1 Differentiate between the parasympathetic and sympathetic nervous systems in terms of anatomy neurotransmitters used and the effects produced by each system 2 Describe syncope and its relationship to the parasympathetic nervous system Cranial Nerves 1 Oculomotor III mixed cranial nerve responsible for eye ball movement stimulates the lacrimal gland 2 Facial VII mixed cranial nerve stimulates salivation 3 Glossopharyngeal IX mixed cranial nerve involved in swallowing and salivation 4 Vagus X mixed cranial nerve carries 80 of parasympathetic outflow to heart airways liver gallbladder stomach small intestine and part of large intestine Cranial Portion 1 Preganglionic neurons found in ponds or medulla 2 Information carried by 4 cranial nerves III VII IX X 3 80 of PSNS information carried by Vagus X Sacral Portion 1 Preganglionic neurons in sacral region S2 S4 exit via pelvic nerves PSNS Ganglia cranial preganglionic neurons synapse at one of four ganglia 1 Ciliary 2 Pterygopalatine 3 Submandibular 4 Otic Cholinergic Receptors respond to ACh 1 Nicotinic receptors found on sympathetic and parasympathetic cell bodies and dendrites of postganglionic neurons within ganglion can only generate excitatory post synaptic potentials EPSP 2 Muscarinic receptors found on membrane of target tissues innervated by parasympathetic postganglionic axons can generate both EPSP and inhibitory post synaptic potentials IPSP Cholinergic Receptors PSNS Rest and Digest Goal Promote digestion of food and the absorption of nutrients Salivation Lacrimation Urination Defecation Specific Responses to PSNS Increased digestive enzyme hormone secretion Increased smooth muscle activity of the GI tract Constriction of pupils for near vision Decreased heart rate contractility blood pressure Contraction of muscular wall of bladder and intestine promotes urination defecation Increased secretion of the lacrimal glands Clinical Application Syncope Syncope fainting vasovagal reaction transient loss of consciousness resulting from an insufficient suppy of oxygen to the brain insufficient cerebral perfusion from hypotension because of failure of ANS to maintain blood pressure syncope can be avoided by laying down in supine position elevating feet contracting leg and arm muscles to bring more blood back to the heart and increase circulation of blood to the brain
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