Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Dee Unglaub Silverthorn, Ph.D.
H UMAN P HYSIOLOGY 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 Chapter 11
Efferent Division: Autonomic and
Somatic Motor Control
About this Chapter 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
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• Controls
• Smooth & cardiac muscle
• Glands & adipose
• Antagonistic branches
• Parasympathetic
• "Rest & digest"
• Restore body
• Sympathetic
• "Fight or flight"
• Energetic action
Autonomic Division: Homeostatic balancing
Autonomic Division: Homeostatic balancing
Autonomic Division: Homeostatic balancing
Autonomic Division: Homeostatic balancing
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• Hypothalamus
• Water balance
• Temperature
• Hunger
• Pons
• Respiration
• Cardiac
• Vasoconstrictio n
• Medulla
• Respiration
Autonomic Control Centers Autonomic Control Centers
Figure 11-3: Autonomic control centers in the brain
• Coordinates homeostatic responses
• Autonomic
• Endocrine
• Behavioral
• Blood pressure
• Osmolarity
• Tonic regulation
• Antagonistic control
• Receptor directed response
Autonomic Pathways: Communicate to Body
Autonomic Pathways: Communicate to Body
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Autonomic Pathways: Communicate to Body Autonomic Pathways: Communicate to Body
Figure 11-2: The hypothalamus and brain stem initiate autonomic, endocrine, and behavioral responses
• CNS
• Preganglionic neuron
• Ganglion
• Postganglioni c neuron
• Target tissue
Autonomic Pathways: Two Efferent Neurons Autonomic Pathways: Two Efferent Neurons
Figure 11-4: Autonomic pathways
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• Neurotransmitter s
• Receptors
Comparison of sympathetic and Parasympathetic Pathways
Comparison of sympathetic and Parasympathetic Pathways
Figure 11-7: Sympathetic and parasympathetic pathways
• Preganglionic neurons
• Originate in
• Brain stem
• Lower cord
• NT: cholinergic
• Ganglion
• Near target
• Nicotinic receptors
• Postganglionic neuron
Parasympathetic Branch: “Rest and Digest”
Parasympathetic Branch: “Rest and Digest”
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Figure 11-5: Autonomic sympathetic and parasympathetic pathways
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• Constricts
• Pupil
• Bronchioles
• Slows heart
• Stimulates
• Digestion
• Insulin release
• Urination
• Erections
Actions of Parasympathetic Branch
Actions of Parasympathetic Branch
• Preganglionic neuron
• Short
• Origin: spinal cord
• NT: cholinergic
• Ganglia
• Sympathetic chain
• Near spinal cord
• Postganglionic neuron
• Long
Sympathetic Branch: “Fight or Flight”
Sympathetic Branch: “Fight or Flight”
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Autonomic Reflexes: “visceral reflexes”
Autonomic Reflexes: “visceral reflexes”
Figure 13-2: Autonomic reflexes
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Examples of Autonomic Reflexes 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
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Autonomic Effects on Cardiovascular System Autonomic Effects on Cardiovascular System
Target Sympathetic (adrenergic) Parasympathetic (muscarinic)
cardiac output β1, (β2): increases M2: decreases
SA node: heart rate (
chronotropic) β1, (β2)
[4]: increases M2: decreases Atrial cardiac muscle:
contractility (inotropic) β1, (β2)
[4]: increases M2: decreases
at AV node
β1:
increases conduction increases
cardiac muscle automaticity
[4]M2:
decreases conduction Atrioventricular block
[4]Ventricular cardiac muscle
β1, (β2):
increases contractility (inotropic) increases
cardiac muscle automaticity
[4]---
Heart
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Autonomic Effects on Blood Vessels Autonomic Effects on Blood Vessels
Target Sympathetic (adrenergic) Parasympathetic (muscarinic)
vascular smooth muscle in general α1:[5] contracts; β2:[5] relaxes M3: relaxes [4]
renal artery α1[6]: constricts ---
larger coronary arteries α1 and α2[7]: constricts [4] ---
smaller coronary arteries β2:dilates [8] ---
arteries to viscera α: constricts ---
arteries to skin α: constricts ---
arteries to brain α1[9]: constricts [4] ---
arteries to erectile tissue α1[10]: constricts M3: dilates
arteries to salivary glands α: constricts M3: dilates
hepatic artery β2: dilates ---
arteries to skeletal muscle β2: dilates ---
Veins α1 and α2 [11] : constricts
β2: dilates ---
Blood vessels
• Pupil dilation
• Salivation
• Heart beat &
volume
• Dilation
• Blood vessels
• Bronchioles
• Catecholamine release
• Fat breakdown
Stimulatory Actions of Sympathetic Branch
Stimulatory Actions of Sympathetic Branch
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• Digestion
• Pancreas secretion
• Urination
Inhibitory Actions of Sympathetic Branch
Inhibitory Actions of Sympathetic Branch
• Sympathetic stimulation
• Catecholamine release to blood
• Epinephrine
• Norepinephrine
• Travel to:
• Multiple targets
• Distant targets Adrenal Medulla:
A Modified Sympathetic Ganglion Adrenal Medulla:
A Modified Sympathetic Ganglion
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Adrenal Medulla:
A Modified Sympathetic Ganglion Adrenal Medulla:
A Modified Sympathetic Ganglion
Figure 11-10: The adrenal medulla
• Varicosities
• NT released to ECF
• No cleft
• Impact
• Large area
• Slow acting
• Long duration
Synapses in Autonomic Nerves
Synapses in Autonomic Nerves
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Mechanism: Norepinephrine Release and Recycling Mechanism: Norepinephrine Release and Recycling
Figure 11-9: Norepinephrine release at a varicosity of a sympathetic neuron
Review of Efferent Pathways: Motor & Autonomic
Review of Efferent Pathways: Motor & Autonomic
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• Body movement
• Appendages
• Locomotion
• Single neuron
• CNS origin
• Myelinated
• Terminus
• Branches
• Neuromuscular junction
Somatic Motor Division: Controls Skeletal Muscles Somatic Motor Division: Controls Skeletal Muscles
Figure 11-11: Summary of efferent pathways
• 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
Neuronmuscular Junction: Overview
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Neuronmuscular Junction: Overview Neuronmuscular Junction: Overview
Figure 11-12: Anatomy of the neuromuscular junction
• 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 Neuronmuscular Junction:
Mechanism of Signal Conduction
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Neuronmuscular Junction:
Mechanism of Signal Conduction Neuronmuscular Junction:
Mechanism of Signal Conduction
Figure 11-13: Events at the neuromuscular junction
• 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 &
Summary
Summary
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