Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Dee Unglaub Silverthorn, Ph.D. H UMAN P HYSIOLOGY PowerPoint ® Lecture Slide Presentation by Dr. Howard D. Booth, Professor of Biology, Eastern Michigan University AN INTEGRATED APPROACH T H I R D E D I T I O N Chapter 11 Efferent Division: Autonomic and Somatic Motor Control
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings About this Chapter Efferent division and what it controls Pathways receptors and neurotransmitters Antagonistic controls: sympathetic and parasympathetic Control of cardiac, smooth muscle, some adipose tissue and glands in homeostasis CNS control of skeletal muscles through neuromuscular junctions
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Controls Smooth & cardiac muscle Glands & adipose Antagonistic branches Parasympathetic "Rest & digest" Restore body Sympathetic "Fight or flight" Energetic action Autonomic Division: Homeostatic balancing
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Autonomic Division: Homeostatic balancing Figure 11-1: Homeostasis and the autonomic division
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Hypothalamus Water balance Temperature Hunger Pons Respiration Cardiac Vasoconstriction Medulla Respiration Autonomic Control Centers Figure 11-3: Autonomic control centers in the brain
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Coordinates homeostatic responses Autonomic Endocrine Behavioral Blood pressure Osmolarity Tonic regulation Antagonistic control Receptor directed response Autonomic Pathways: Communicate to Body
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Autonomic Pathways: Communicate to Body Figure 11-2: The hypothalamus and brain stem initiate autonomic, endocrine, and behavioral responses
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings CNS Preganglionic neuron Ganglion Postganglionic neuron Target tissue Autonomic Pathways: Two Efferent Neurons Figure 11-4: Autonomic pathways
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Neurotransmitters Receptors Comparison of sympathetic and Parasympathetic Pathways Figure 11-7: Sympathetic and parasympathetic pathways
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Preganglionic neurons Originate in Brain stem Lower cord NT: cholinergic Ganglion Near target Nicotinic receptors Postganglionic neuron Parasympathetic Branch: “Rest and Digest”
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 11-5: Autonomic sympathetic and parasympathetic pathways
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Constricts Pupil Bronchioles Slows heart Stimulates Digestion Insulin release Urination Erections Actions of Parasympathetic Branch
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Preganglionic neuron Short Origin: spinal cord NT: cholinergic Ganglia Sympathetic chain Near spinal cord Postganglionic neuron Long NT: adrenergic Sympathetic Branch: “Fight or Flight”
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Examples of Autonomic Reflexes Cold Water (Whole Body) Immersion causes tachycardia Exposure of face to cold water causes bradycardia: Mammalian Diving Reflex via Vagal Nerve Pupillary Reflex-Pupil Constricting in response to light Baroreceptor Reflex- Low BP in carotid sinus results in tachycardia and blood vessel constriction Carotid Sinus Reflex- Increased pressure within or external manipulation of carotid sinus results in bradycardia Dilation of Blood vessels as body temperature increases Secretion of epinephrine and norepinephrine from the adrenal medulla in response to fear or stress Sweating in response to increased body temperature
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Autonomic Effects on Cardiovascular System TargetSympatheticSympathetic (adrenergic)adrenergicParasympatheticParasympathetic (muscarinic)muscarinic cardiac outputβ1β1, (β2): increasesβ2M2M2: decreases SA nodeSA node: heart rate (chronotropic)chronotropicβ1β1, (β2) [4] : increasesβ2 [4]M2: decreases AtrialAtrial cardiac muscle: contractility (inotropic)cardiac muscleinotropic β1, (β2) [4] : increases [4]M2: decreases at AV nodeAV node β1: increases conduction increases cardiac muscle automaticity [4]conductioncardiac muscle automaticity [4] M2: decreases conduction Atrioventricular block [4] Atrioventricular block [4] VentricularVentricular cardiac musclecardiac muscle β1, (β2): increases contractility (inotropic) increases cardiac muscle automaticity [4]inotropiccardiac muscle automaticity [4] --- Heart
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Autonomic Effects on Blood Vessels TargetSympatheticSympathetic (adrenergic)adrenergicParasympatheticParasympathetic (muscarinic)muscarinic vascular smooth musclevascular smooth muscle in generalα1: [5] contracts; β2: [5] relaxes [5] M3M3: relaxes [4] [4] renal arteryα1 [6] : constricts [6]--- larger coronary arteriescoronary arteriesα1 and α2 [7] : constricts [4] [7] [4] --- smaller coronary arteriescoronary arteriesβ2:dilates [8] [8] --- arteriesarteries to visceravisceraα: constricts--- arteriesarteries to skinskinα: constricts--- arteriesarteries to brainbrainα1 [9] : constricts [4] [9] [4] --- arteriesarteries to erectile tissueerectile tissueα1 [10] : constricts [10]M3: dilates arteriesarteries to salivary glandssalivary glandsα: constrictsM3: dilates hepatic arteryβ2: dilates--- arteriesarteries to skeletal muscleskeletal muscleβ2: dilates--- Veins α1 and α2 [11] : constricts β2: dilates [11] --- Blood vessels
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Pupil dilation Salivation Heart beat & volume Dilation Blood vessels Bronchioles Catecholamine release Fat breakdown Ejaculation Stimulatory Actions of Sympathetic Branch
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Digestion Pancreas secretion Urination Inhibitory Actions of Sympathetic Branch
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Sympathetic stimulation Catecholamine release to blood Epinephrine Norepinephrine Travel to: Multiple targets Distant targets Adrenal Medulla: A Modified Sympathetic Ganglion
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Adrenal Medulla: A Modified Sympathetic Ganglion Figure 11-10: The adrenal medulla
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Varicosities NT released to ECF No cleft Impact Large area Slow acting Long duration Synapses in Autonomic Nerves Figure 11-8: Varicosities of autonomic neurons
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Mechanism: Norepinephrine Release and Recycling Figure 11-9: Norepinephrine release at a varicosity of a sympathetic neuron
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Review of Efferent Pathways: Motor & Autonomic Figure 11-11: Summary of efferent pathways
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Body movement Appendages Locomotion Single neuron CNS origin Myelinated Terminus Branches Neuromuscular junction Somatic Motor Division: Controls Skeletal Muscles Figure 11-11: Summary of efferent pathways
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Terminal boutons Synaptic cleft Filled with a fibrous Matrix (collagen) AChE Hold axon terminal and motor end plate together Motor end plate On muscle Nicotinic receptors Neuronmuscular Junction: Overview
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Neuronmuscular Junction: Overview Figure 11-12: Anatomy of the neuromuscular junction
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Axon terminal AP signals ACh release Motor end plate 2 ACh bind opens cation channel Na + influx Membrane depolarized Stimulates fiber contraction Neuronmuscular Junction: Mechanism of Signal Conduction
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Neuronmuscular Junction: Mechanism of Signal Conduction Figure 11-13: Events at the neuromuscular junction
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Autonomic branches: sympathetic and parasympathetic Regulate glands, smooth & cardiac muscles Team with endocrine to regulate homeostasis Are regulated by hypothalamus, pons & medulla Have pathways with 2 neurons and a ganglion Use varicosities to release NTs Have diverse receptors: tonic & antagonistic regulation Summary
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Efferent motor neurons control skeletal muscles Single long myelinated neuron from CNS Neuromuscular junction structure & mechanism Summary