Chp 11 Part B 2024.pdf

Physiology: Chp 11 Part B Autonomic & Somatic Motor Control Juan J. Bustamante, Ph.D. Assistant Professor Pharmaceutical Science Phone (361) 221-0643 Email: [email protected] Office: Room 223 © 2016 Pearson...

Physiology: Chp 11 Part B Autonomic & Somatic Motor Control Juan J. Bustamante, Ph.D. Assistant Professor Pharmaceutical Science Phone (361) 221-0643 Email: [email protected] Office: Room 223 © 2016 Pearson Education, Inc.  Why do we only see antagonistic control at the SA only not the ventricle, veins & arterioles? © 2016 Pearson Education, Inc. Figure 15.14 Figure 15.11a Resistance and flow © 2016 Pearson Education, Inc. © 2016 Pearson Education, Inc. Figure 15.14 © 2016 Pearson Education, Inc.  Sympathetic ganglia in two ganglion chains along either side of the vertebral column © 2016 Pearson Education, Inc.  Vagus Nerve Contains about 75% of all parasympathetic fibers Sensory information from internal organs to brain Output from brain to organs © 2016 Pearson Education, Inc. © 2016 Pearson Education, Inc. Figure 11.6 Sympathetic and parasympathetic neurotransmitters and receptors Sympathetic pathways Parasympathetic pathways use acetylcholine and use acetylcholine. norepinephrine. CNS CNS preganglionic neurons release acetylcholine ACh postganglionic cell Nicotinic receptor (nAChR) Autonomic ganglion Postganglionic Postganglionic sympathetic neurons parasympathetic secrete neurons secrete Norepinephrine ACh Adrenergic (NE) Muscarinic receptor receptor (mAChR) T Target tissue T © 2016 Pearson Education, Inc. © 2016 Pearson Education, Inc. © 2016 Pearson Education, Inc.  Beta-blockers can be selective or non-selective. Selective beta-blockers mostly affect the heart, while non-selective ones affect other parts of the body. © 2016 Pearson Education, Inc. https://www.lecturio.com/magazine/alpha-and-beta-blockers/ Figure 11.9-1 Efferent Divisions of the Nervous System Summary of Sympathetic and Parasympathetic Branches AUTONOMIC PATHWAYS Parasympathetic Pathway Ganglion Muscarinic CNS receptor Autonomic targets: Smooth and cardiac muscles Some endocrine and exocrine glands ACh ACh Some adipose tissue Nicotinic receptor Sympathetic Pathway α receptor Nicotinic receptor CNS NE β 1 receptor ACh β 2 receptor E Q FIGURE QUESTIONS Adrenal Sympathetic Pathway Using the figure, compare: (a) number of neurons in somatic E CNS motor and autonomic pathways (b) receptors on target cells of somatic Adrenal medulla motor, sympathetic, and Blood vessel parasympathetic pathways Adrenal cortex (c) neurotransmitters used on target KEY cells of somatic motor, sympathetic, and parasympathetic pathways ACh = acetylcholine (d) receptor subtypes for epinephrine E = epinephrine with subtypes for norepinephrine NE = norepinephrine © 2016 Pearson Education, Inc.  Adrenal Medulla Neuroendocrine tissue Associated with the sympathetic branch Primary neurohormone is epinephrine (more commonly known as adrenaline) Secreted into the blood © 2016 Pearson Education, Inc. Figure 11.8 The adrenal medulla The adrenal medulla secretes epinephrine into the blood. Adrenal cortex is a true endocrine gland. Adrenal medulla is a modified sympathetic ganglion. Adrenal gland Kidney The chromaffin cell is a modified ACh postganglionic sympathetic Blood vessel neuron. Preganglionic Spinal cord sympathetic neuron Epinephrine is a To target tissues neurohormone that Adrenal medulla enters the blood. © 2016 Pearson Education, Inc.  Autonomic Receptors Have Multiple Subtypes Sympathetic receptors use alpha and beta adrenergic receptors with subtypes Epinephrine weekly binds with α-receptors – reinforcing vasoconstriction. Epinephrine strongly binds to ꞵ2-receptors, found on vascular smooth muscle of the heart, liver, and skeletal muscle arterioles. The receptors are not innervated and therefore respond primarily to circulating epinephrine. Activation of vascular ꞵ2-receptors by epinephrine cause vasodilation. © 2016 Pearson Education, Inc.  Epinephrine strongly binds to ꞵ2-receptors, found on vascular smooth muscle of the heart, liver, and skeletal muscle arterioles. Activation of vascular ꞵ2-receptors by epinephrine cause vasodilation. © 2016 Pearson Education, Inc. © 2016 Pearson Education, Inc. https://www.accessdata.fda.gov/drugsatfda_docs/label/2012/019430s053lbl.pdfv © 2016 Pearson Education, Inc.  Anaphylaxis Shock Hives dilate bronchoconstrict https://nursekey.com/wp-content/uploads/2016/07/image02017.jpeg © 2016 Pearson Education, Inc. https://businessmirror.com.ph/2018/08/09/anaphylactic-shock-a-life-threatening-reaction/ © 2016 Pearson Education, Inc. https://www.optometricmanagement.com/archive/2009/February/Supplements/Alcon/images/OM_Alcon_Suppl_February_A02_Fig02.jpg © 2016 Pearson Education, Inc. © 2016 Pearson Education, Inc. © 2016 Pearson Education, Inc.  Epipen: When given intramuscularly or subcutaneously it has a rapid onset and short duration of action. Epinephrine acts on both alpha and beta adrenergic receptors. Through its action on alpha adrenergic receptors, epinephrine lessens the vasodilation and increased vascular permeability that occurs during anaphylaxis, which can lead to loss of intravascular fluid volume and hypotension. © 2016 Pearson Education, Inc. https://www.accessdata.fda.gov/drugsatfda_docs/label/2012/019430s053lbl.pdfv  Autonomic Pathways Control Smooth and Cardiac Muscle and Glands The neuroeffector junction is the synapse between a postganglionic autonomic neuron and its target cells (effector). Note: The structure of an autonomic synapse differs from the model synapses © 2016 Pearson Education, Inc.  Autonomic Pathways Control Smooth and Cardiac Muscle and Glands Autonomic neuron targets: Smooth muscle Cardiac muscle Many exocrine glands Few endocrine glands Lymphoid tissues Some adipose tissue © 2016 Pearson Education, Inc. Figure 11.7a Autonomic synapses Varicosities are series of swollen areas at their distal ends containing neurotransmitters Neurotransmitters diffuse in synapse and bind to receptor Autonomic varicosities release neurotransmitter over the surface of target cells. Vesicle containing neurotransmitter Varicosity Axon of postganglionic Mitochondrion autonomic neuron Smooth muscle cells Varicosities Note: The primary autonomic neurotransmitters, acetylcholine and norepinephrine, can be synthesized in the axon varicosities © 2016 Pearson Education, Inc. Figure 11.7b Autonomic synapses Slide 1 Adrenergic receptors in postganglionic sympathetic target cells Norepinephrine (NE) release and removal at a sympathetic neuroeffector junction Action potential arrives at the varicosity. Depolarization opens voltage-gated Ca2+ channels. Axon varicosity Ca2+ entry triggers MAO exocytosis of synaptic vesicles. Tyrosine Axon NE binds to adrenergic receptor on target. NE Action potential Receptor activation ceases when Exocytosis NE diffuses away from the synapse. Voltage-gated Ca2+ channel Active transport Ca2+ NE is removed from the synapse. NE Diffuses away Blood G NE can be taken back into vessel synaptic vesicles for re-release. Response Adrenergic Target cell NE is metabolized by receptor monoamine oxidase (MAO). © 2016 Pearson Education, Inc. Figure 11.7b Autonomic synapses Slide 2 Norepinephrine (NE) release and removal at a sympathetic neuroeffector junction Action potential arrives at the varicosity. Tyrosine Axon NE Action potential Blood vessel Target cell © 2016 Pearson Education, Inc. © 2016 Pearson Education, Inc. Figure 11.7b Autonomic synapses Slide 3 Norepinephrine (NE) release and removal at a sympathetic neuroeffector junction Action potential arrives at the varicosity. Depolarization opens voltage-gated Ca2+ channels. Tyrosine Axon NE Action potential Voltage-gated Ca2+ channel Ca2+ Blood vessel Target cell © 2016 Pearson Education, Inc. Figure 11.7b Autonomic synapses Slide 4 Norepinephrine (NE) release and removal at a sympathetic neuroeffector junction Action potential arrives at the varicosity. Depolarization opens voltage-gated Ca2+ channels. Ca2+ entry triggers exocytosis of synaptic vesicles. Tyrosine Axon NE Action potential Exocytosis Voltage-gated Ca2+ channel Ca2+ NE Blood vessel Target cell More neurotransmitters © 2016 Pearson Education, Inc.  Coding the strength of a stimulus Frequency of action potentials determines how many neurotransmitter is released © 2016 Pearson Education, Inc. Figure 11.7b Autonomic synapses Slide 5 What is different about the receptor number? Norepinephrine (NE) release and removal at a sympathetic neuroeffector junction Action potential arrives at the varicosity. Depolarization opens voltage-gated Ca2+ channels. Ca2+ entry triggers exocytosis of synaptic vesicles. Tyrosine Axon NE binds to adrenergic receptor on target. NE Action potential The more neurotransmitter means Exocytosis Voltage-gated Ca2+ channel a longer or stronger response Ca2+ NE The autonomic control of target by modulating the concentration of Blood vessel G neurotransmitter in the synapse Response Adrenergic Target cell receptor Neurotransmitters (NT) diffuse in synapse and bind to receptor Note: All adrenergic receptors are G-protein coupled receptors rather than ion channel – the response is slower to start and stop © 2016 Pearson Education, Inc. Figure 11.7b Autonomic synapses Slide 6 Norepinephrine (NE) release and removal at a sympathetic neuroeffector junction Action potential arrives at the varicosity. Depolarization opens voltage-gated Ca2+ channels. Ca2+ entry triggers exocytosis of synaptic vesicles. Tyrosine Axon NE binds to adrenergic receptor on target. NE Action potential Receptor activation ceases when Exocytosis NE diffuses away from the synapse. Voltage-gated Ca2+ channel NT removal Ca2+ NE Diffuses away Blood G vessel Response Adrenergic Target cell receptor © 2016 Pearson Education, Inc. Figure 11.7b Autonomic synapses Slide 7 Norepinephrine (NE) release and removal at a sympathetic neuroeffector junction Action potential arrives at the varicosity. Depolarization opens voltage-gated Ca2+ channels. Ca2+ entry triggers exocytosis of synaptic vesicles. Tyrosine Axon NE binds to adrenergic receptor on target. NE Action potential Receptor activation ceases when Exocytosis NE diffuses away from the synapse. Voltage-gated Ca2+ channel Active transport NT removal Ca2+ NE is removed from the synapse. NE Diffuses away Blood G vessel Response Adrenergic Target cell receptor © 2016 Pearson Education, Inc. Figure 11.7b Autonomic synapses Slide 8 Norepinephrine (NE) release and removal at a sympathetic neuroeffector junction Action potential arrives at the varicosity. Depolarization opens voltage-gated Ca2+ channels. Ca2+ entry triggers exocytosis of synaptic vesicles. Tyrosine Axon NE binds to adrenergic receptor on target. NE Action potential Receptor activation ceases when Exocytosis NE diffuses away from the synapse. Voltage-gated Ca2+ channel Active transport NT removal Ca2+ NE is removed from the synapse. NE Diffuses away Blood G NE can be taken back into vessel synaptic vesicles for re-release. Response Adrenergic Target cell receptor © 2016 Pearson Education, Inc. Figure 11.7b Autonomic synapses Slide 9 Norepinephrine (NE) release and removal at a sympathetic neuroeffector junction Action potential arrives at the varicosity. Depolarization opens voltage-gated Ca2+ channels. Axon varicosity Ca2+ entry triggers MAO exocytosis of synaptic vesicles. Tyrosine Axon NE binds to adrenergic receptor on target. NE Action potential Receptor activation ceases when Exocytosis NE diffuses away from the synapse. Voltage-gated Ca2+ channel Active transport Ca2+ NT removal NE is removed from the synapse. NE Diffuses away Blood G NE can be taken back into vessel synaptic vesicles for re-release. Response Adrenergic Target cell NE is metabolized by receptor monoamine oxidase (MAO). © 2016 Pearson Education, Inc.  Autonomic Receptors Have Multiple Subtypes Muscarinic receptors in postganglionic parasympathetic target cells G protein–coupled Second messenger pathways At least five subtypes © 2016 Pearson Education, Inc. Figure 8.20 Synthesis and recycling of acetylcholine Slide 1 Ach is synthesized from choline and acetyl CoA in the varicosities Mitochondrion Acetyl CoA CoA Axon Acetylcholine (ACh) is made terminal Enzyme from choline and acetyl CoA. A Acetylcholine Ch A Synaptic Ch vesicle In the synaptic cleft, ACh is rapidly Ch broken down by the enzyme acetylcholinesterase. A Ch Choline is transported back into the axon terminal by cotransport Na+ Ch Choline Cholinergic with Na+. A receptor A Ch Recycled choline is used to make Acetate Acetylcholinesterase (AChE) Postsynaptic more ACh. cell © 2016 Pearson Education, Inc. © 2016 Pearson Education, Inc. © 2016 Pearson Education, Inc. © 2016 Pearson Education, Inc.