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Chapter 9

Chapter 9. The Autonomic Nervous System “ Fight or Flight Response System ”. The Autonomic Nervous System. Autonomic nervous system. Sympathetic nervous system 1. neurotransmitter = 2. secretes 3. effects on physiology: a) b) c) d). Autonomic nervous system.

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Chapter 9

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  1. Chapter 9 The Autonomic Nervous System “Fight or Flight Response System”

  2. The Autonomic Nervous System

  3. Autonomic nervoussystem • Sympathetic nervous system • 1. neurotransmitter = • 2. secretes • 3. effects on physiology: • a) • b) • c) • d)

  4. Autonomic nervoussystem • Parasympathetic nervous system • 1. Neurotransmitter = • 2. effects on physiology • a) • b) • c)

  5. Neural Control of Involuntary Effectors • Autonomic nervous system (ANS): • Innervates _______ whose functions are not usually under voluntary control. • Effectors include _________ and _____________ and __________. • Effectors are part of visceral organs and blood vessels.

  6. Autonomic Control Centers of the Brain • 1. Hypothalamus • 2. Pituitary • 3. Mamillary Body • 4. Pons • 5. Medulla

  7. Autonomic Neurons BSE

  8. Visceral Effector Organs • Involuntary effectors are somewhat independent of their innervation. • _________________________________ • . • Example of this???? • Cardiac and many smooth muscles can ___________rhythmically in absence of nerve stimulation.

  9. Sympathetic Division (continued)

  10. Sympathetic and Parasympathetic Divisions • All fibers within S and P secrete 1 of 2 transmitter substances: • Acetylcholine – _______________ • Noerpinephrine - ________________

  11. Sympathetic vs Parasympathetic

  12. Effects on Major Organs Nasal, lacrimal, salivary, GIT Parasympathetic: Glands: ___________________ Sympathetic Glands: constricts blood vessels going to gland = _____________ quantity of secretion Sweat Glands Parasympathetic: ______________ Sympathetic: _________________

  13. Adrenal Glands • Located above _____________ • Each adrenal is divided into 2 parts: • Cortex_____________ • Medulla________________ • Adrenal medulla secretes epinephrine (_____) and norepinephrine (_____) when stimulated by the _______________ • _______ is mainly secreted from nerve endings • _______ can be converted to Epi in adrenal medulla

  14. Parasympathetic Division • Preganglionic fibers originate in __________, medulla, pons; sacral levels of the spinal column. • Preganglionic fibers synapse in terminal ganglia located next to or within organs innervated. • Most parasympathetic fibers do not travel within spinal nerves. • Do not ____________ vessels, sweat glands, and arrector pili muscles.

  15. Parasympathetic Division (continued) • Vagus (X): • Innervates _________, ___________,___________, stomach, pancreas, liver, small intestine and upper half of the large intestine. • ________________ fibers from the sacral level innervate the lower half of large intestine, the rectum, urinary and reproductive systems.

  16. Sympathetic Effects • Fight or flight response. • Release of ___________________ from postganglionic fibers and ____________________ from adrenal medulla. • Mass activation prepares for intense activity. • Heart rate (HR) _____________ • Bronchioles _______________ • Blood [glucose] _________________.

  17. Parasympathetic Effects • Normally not activated as a whole. • Stimulation of separate parasympathetic nerves. • Release ACh as NT. • Relaxing effects: • __________________ HR. • _______________ visceral blood vessels. • ____________________ digestive activity.

  18. Adrenergic and Cholinergic Synaptic Transmission • ACh is NT for all preganglionic fibers of both sympathetic and _____________________ nervous systems. • Transmission at these synapses is termed cholinergic: • ACh is NT released by most postganglionic parasympathetic fibers at synapse with effector. • Axons of postganglionic neurons have numerous varicosities along the axon that contain NT.

  19. Adrenergic and Cholinergic Synaptic Transmission (continued) • NT released by most postganglionic _______________ nerve fibers is NE. • Epi, released by the adrenal medulla is synthesized from the same precursor as NE. • Collectively called ________________.

  20. Responses to Adrenergic Stimulation • Beta adrenergic receptors: • Produce their effects by stimulating production of cAMP. • NE binds to receptor. • G-protein dissociates into a subunit or bg- complex. • Depending upon tissue, either a subunit or bg-complex produces the effects. • Alpha subunit activates adenylate cyclase, producing cAMP. • cAMP activates protein kinase, opening ion channels.

  21. ___________________ – parasympathetic postganglionic fibers = cholinergic • ___________________– sympathetic postganglionic fibers = adrenergic

  22. Responses to Adrenergic Stimulation (continued) • Alpha1 adrenergic receptors: • Produce their effects by the production of ___________________ • Epi binds to receptor. • Ca2+ binds to ____________________. • Calmodulin activates protein kinase, modifying enzyme action. • Alpha2 adrenergic receptors: • Located on ________________terminal. • Decreases release of ___________. ___________________________ feedback control. • Located on postsynaptic membrane. • When activated, produces vasoconstriction.

  23. Responses to Adrenergic Stimulation (continued) • Has both excitatory and inhibitory effects. • Responses due to different membrane receptor proteins. • a1 : constricts __________smooth muscles. • a2 : contraction of ____________muscle. • b1 : ___________ HR and force of contraction. • b2 : __________bronchial smooth muscles. • b3: adipose tissue, function unknown.

  24. Responses to Cholinergic Stimulation • All somatic motor neurons, all preganglionic and most postganglionic parasympathetic neurons are cholinergic. • Release _____________ as NT. • Somatic motor neurons and all preganglionic autonomic neurons are excitatory. • Postganglionic axons, may be excitatory or inhibitory. • Muscarinic receptors: • __________ binds to receptor. • Requires the mediation of G-proteins. • bg-complex affects opening or closing a channel, or activating enzymes.

  25. Responses to Cholinergic Stimulation (continued) • Nicotinic receptors (ligand-gated): • ACh binds to 2 nicotinic receptor binding sites. • Causes ion channel to open within the receptor protein. • Opens a _____________channel. • Always _____________.

  26. Responses to Cholinergic Stimulation (continued)

  27. Other Autonomic NTs • Certain nonadrenergic, noncholinergic postganglionic autonomic axons produce their effects through other NTs. • _________. • _________. • NO.

  28. Organs With Dual Innervation • Most visceral organs receive dual innervation (innervation by both sympathetic and parasympathetic fibers). • Antagonistic effects: • Sympathetic and parasympathetic fibers innervate the same cells. • Actions counteract each other. • _______________________. • Complementary: • Sympathetic and parasympathetic stimulation produces similar effects. • _________________________________. • Cooperative: • Sympathetic and parasympathetic stimulation produce different effects that work together to produce desired effect. • _____________________.

  29. Organs Without Dual Innervation • Regulation achieved by increasing or decreasing firing rate. • Adrenal medulla, arrector pili muscle, sweat glands, and most blood vessels receive only sympathetic innervation. • _________________________________

  30. Control of the ANS by Higher Brain Centers • Sensory input transmitted to brain centers that integrate information. • Can modify activity of preganglionic autonomic neurons. • Medulla: • Most directly controls activity of _____________ system. • Location of centers for control of cardiovascular, pulmonary, urinary, reproductive and digestive systems. • Hypothalamus: • _____________________________. • Cerebral cortex and limbic system: • Responsible for visceral responses that are characteristic of emotional states.

  31. Ractopamine • _______________________ agonist • Approved for improving growth in meat animals • _____________________ and feed conversion but do not affect feed intake in feedlot cattle. • Hogs -

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