1 / 23

Efferent Peripheral NS: The Autonomic & Somatic Motor Divisions

Ch 11:. Efferent Peripheral NS: The Autonomic & Somatic Motor Divisions. Homeostasis and the Autonomic Division. BP, HR, Resp., H 2 O balance, Temp. . . Mostly dual reciprocal innervation Sympathetic: flight-or-fight Parasympathetic: rest and digest.

christy
Download Presentation

Efferent Peripheral NS: The Autonomic & Somatic Motor Divisions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Ch 11: Efferent Peripheral NS: The Autonomic & Somatic Motor Divisions

  2. Homeostasis and theAutonomic Division • BP, HR, Resp., H2O balance, Temp. . . • Mostly dual reciprocal innervation • Sympathetic: flight-or-fight • Parasympathetic: rest and digest

  3. Autonomic pathway: 2 Efferent Neurons in Series Preganglionic neuron cell body in CNS Synapsis in autonomic ganglion outside CNS  divergence Postganglionic neurons target cells?

  4. = Thoracolumbar • division (T1 to L2) • Preganglionic neurons from thoracolumbar region of spinal cord • Pre and paravertebral ganglia • Long postganglionic axons secrete NE onto adrenergic receptors

  5. = Craniosacral Division • Long preganglionic axons from brain & S2- S4 • Intramural ganglia • Postganglionic neurons secrete Ach onto cholinergic muscarinic receptors

  6. Most Common Autonomic NTs: • Acetylcholine (ACh) ACh neurons & ACh receptors are called cholinergic(nicotinic or muscarinic).Located at autonomic preganglionic & para-sympathetic postganglionic synapses • Norepinephrine (NE) NE neurons & receptors are called (nor) adrenergic ( and ). Located at sympathetic postganglionic synapses Fig 11-7

  7. NTs of Autonomic NS Compare to Fig 11-7  andβ

  8. Neuroeffector Junction of ANS = Synapse between postganglionic cell and target organ Most are different from model synapse: Axon has varicositiescontaining neurotransmitter (compare to Fig 8-20, p. 270) Fig 11-8

  9. Varicosity of Sympathetic Neuron Fig11-9

  10. Two Types of Cholinergic Receptors: 1) Nicotinic cholinergic receptor • Nicotine = agonist • In autonomic ganglia & somatic NS • Directly opens a Na+ / K+ channel:  ? • Curare = antagonist

  11. 2) Muscarinic cholinergic receptor • Muscarine = agonist • Found in neuro-effector junctions of parasympathetic branch • G-protein coupled mechanisms • Atropine = antagonist Amanita muscaria

  12. MuscarinicACh Receptors are G-protein Mediated Example: Sweat Glands Other examples have more complex with 2nd messenger mechanisms

  13. Summary: Pre- & Postganglionic Parasympathetic Neurons Release ACh nicotinic muscarinic Receptors

  14. Adrenergic Receptors Found in neuro- effector junctions of sympathetic branch G protein linked, with various 2nd mess. mech. Receptors:NE > E (most common) Excitation [Ca2+]in  muscle contraction or secretion by exocytosis.  Inhibition of GI tract and pancreas

  15.  - Receptors Clinically more important • 1 Excitation heart (E = NE) • 2 usually inhibitory: smooth muscle relaxation of some blood vessels and bronchioles(E > NE!) • “ -blockers” = Antagonists (e.g.: Propranolol and metoprololToprol-XL)

  16. Termination of NT Activity • ACh esterase • Catecholamine reuptake • repackaging • degradation (MAO) Fig 8-22 Fig 11-9

  17. Somatic Motor Division • Pathway consists of single neuron from CNS to target • Neuromuscular junction: nicotinic cholinergic receptors • Always excitatory  muscle contracts

  18. Somatic Neuromuscular Junction Fig 11-13

  19. Agonists and Antagonist of ANS Direct Antagonists • Atropin muscarinic • Curare  nicotinic • Propranolol  1 and 2 • Metoprolol  1

  20. See Table 11-3 Indirect (Ant)agonists • Botulinum toxin  inhibits Ach release • Neostigmine inhibits AchE(organophosphate insecticides, such as para-, malathion) Therapy for MG • Cocaine prevents NE reuptake • Amphetamines stimulate NE release

  21. Also review Tables 11-1 11-4 11-5 A Powerful Addiction

  22. Review Fig 11-11 The End

More Related