Download Autonomic nervous system

Objectives
Autonomic nervous system
Sompol Tapechum, M.D., Ph.D.
Department of Physiology
Faculty of Medicine Siriraj Hospital
เมื่อจบบทเรียน นักศึกษาสามารถ
1. บอกความแตกตางระหวาง Autonomic และ Somatic
nervous system ได
2. บอกชนิดและองคประกอบของ Autonomic nervous
system แตละชนิดได
3. บอกกลไกการทํางานของ Autonomic nervous system ได
4. บอกหนาที่ของ Autonomic nervous system ตออวัยวะตางๆ
ในรางกายได
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Organization of Nervous System
Organization of Nervous System
„ ระบบประสาทสามารถแบงออกไดเปน 2 ระบบ ตามลักษณะการควบคุมการทํางาน
„ ระบบประสาทแบงตามกายวิภาคเปน 2 สวน คือ
Brain
„
Spinal
cord
ระบบประสาทกลาง (Central nervous system:
CNS) ไดแก สมอง (brain) และ ไขสันหลัง
(spinal cord)
„ ทําหนาที่รับรู, ประมวลผล และสั่งการ
„
Nerves
„
ของรางกาย คือ
„
„
ระบบประสาทกาย (Somatic nervous system)
ระบบประสาทอัตโนวัติ (Autonomic nervous system; ANS)
นําสัญญาณรับรูตัวกระตุน (afferent)
นําสัญญาณสั่งการตอบสนอง (efferent)
3
Somatic VS Autonomic
External
Environment
Somatic
Nervous
System
Efferent
Voluntary response
nt
re
4
Reflex response
Responses
Afferent
en
t
Central
Nervous
System
(CNS)
Eff
er
t
en
Somatic Nervous System
Efferent
nt
r
fe
Ef
Voluntary organs:
• Skeletal muscle
Autonomic
Internal
Nervous
Environment
System
re
fe
Af
fe
Af
Central
Nervous
System
(CNS)
Somatic nervous system
Visceral
receptor
Stimuli
Somatosensory
receptor
Afferent
Afferent
ระบบประสาทสวนปลาย (Peripheral nervous
system: PNS) ไดแก เสนประสาท (nerves)
และปมประสาท (ganglia)
„
2
Involuntary organs:
• Smooth muscle
• Cardiac muscle
• Glands: exocrine, endocrine
Autonomic Nervous System
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Efferent
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Somatic Reflex Arc
Autonomic nervous system
„ Reflex response only
1.Sensory receptor
2.Afferent (sensory) neuron
3.(Interneuron)
4.Efferent (motor) neurons
5.Effector (skeletal muscle)
Baroreceptor Reflex
(control of Cardiovascular system)
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Autonomic reflex arc
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Afferent
Somatic
1.Visceral receptor
2.Afferent neurons
(Interneuron)
3.Efferent neurons
•
Preganglionic
•
postganglionic
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4.Effector
Efferent (motor) pathway
Autonomic
Sensory receptors
Skin, muscle, bone,
joint
Visceral organs, blood
vessels
Sensory neurons
Dorsal root ganglia,
cranial nuclei
Dorsal root ganglia,
cranial nuclei
„Present
„ Sparsely distributed
„Present
„ Few
„Present
„ Few
„Present
„ None
„ Osmoreceptors,
Receptors
„Pain
„Temperature
„Touch
„Proprioceptors
„Special receptors
baroreceptors,
chemoreceptors
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Efferent pathways
• Somatic efferent
• One neuron
• α-Motor neuron
• type A fiber
• Autonomic efferent
• Autonomic ganglia
• Two neurons
•Preganglionic
• type B fiber
•Postganglionic
• type C fiber
Ganglion = collection of neurons outside CNS
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12
Neuro-effector junction
Efferent
Somatic
Motor neurons
„ No specialized postsynaptic sites
„Anterior horn cells of
„Intermediolateral
„ Postsynaptic nerve endings have several
spinal cord
„Some cranial motor
nuclei
column of spinal cord
„Some cranial motor
nuclei
„ Postsynaptic nerve endings are several hundred
Numbers of
neurons in efferent
pathway
Effector organs
„ No specialized presynaptic sites: no active zones
Autonomic
One
„Skeletal muscle
Two
„Preganglionic
„Postganglionic
swellings(Varicosities)
nanometers from the effectors
„
more diffuse control over target tissue
„ Smooth muscle
En passant
„ Cardiac muscle
„ Glands: exocrine,
endocrine
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Sympathetic nervous system:
Preganglionic neurons
Classes of ANS
„ ระบบประสาท autonomic โดยทั่วไปแบงเปน 2 ระบบ
„
„
„ Thoracolumbar outflow
Sympathetic nervous system
„
(C8 or T1- L3 or L4)
Fight or Flight
„ Cells are in intermediolateral
column of spinal cord
Parasympathetic nervous system
„
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„ Type B fiber
Rest and Digest
„ Short
„ Neurotransmitter release:
„ Dual innervation system
„ อวัยวะสวนใหญถูก supply ดวยทั้ง sympathetic และ
parasympathetic nervous system
„ ทั้งสองระบบมักจะกอใหเกิดการตอบสนองตรงขามกัน
Acetylcholine (ACh) =
cholinergic fiber
„ Divergence (1:10)
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Sympathetic nervous system:
Postganglionic neurons
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Sympathetic nervous system:
Postganglionic neurons
„ Sympathetic ganglia
„ paravertebral
„ preverebral
„ Type C fiber, Long
„ Neurotransmitter released:
norepinephrine = adrenergic fiber
„ Exception
„ releases ACh at sweat glands and
blood vessels in skeletal muscle
„ chromaffin cells in adrenal medulla
release epinephrine
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Sympathetic:
Neurotransmission
Autonomic nervous system
Thoracolumbar
outflow
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Sympathetic nervous system:
Ganglionic transmission (1)
„ Preganglionic neurons
Sympathetic nervous system:
Ganglionic transmission (2)
„ Actually, there are others
Na+
neurotransmitters
released at ganglia
„ involve both fast and
slow synaptic
transmission
release ACh
„ Postsynaptic receptors are
nicotinic ACh receptors
„
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Permeable to Na+ and K+
„ Response with fast EPSP
K+
Note
„ Neuronal (NN) and muscular (NM) type nicotinic receptors are
distinct pharmachologically
„ Antagonist for NN are trimethophan and hexamethonium
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Adrenergic receptors
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Adrenergic receptor: α2 and β
„ Receptors for norepinephrine and epinephrine
„ Metabotropic receptors: G-protein couple receptors
„ There are at lease 4 types: α1, α2, β1 and β2
Second
messenger
Distribution
α1
α2
β1
β2
IP3
DAG
↓cAMP
↑cAMP
↑cAMP
Heart
Airway, GI
Urogenital
Blood vessels Presynaptic
terminal
Sphincter
Agonist
Antagonist
Clonidine
Prazosin
Isoproterenol Isoproterenol
Dobutamine Terbutaline
Propanolol
Propanolol
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Adrenergic receptor: α1
Sympathetic responses
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Parasympathetic nervous system
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Autonomic nervous system
„ Preganglionic neurons
Craniosacral outflow (brainstem and
sacral spinal cord S2-S4)
„ Type B fiber, Long
„ Neurotransmitter release: ACh
(cholinergic fiber)
„ Postganglionic neurons
„ Parasympathetic ganglia are near or
in visceral organ supplied
„ Type C fiber, Short
„ Neurotransmitter release: ACh
(cholinergic fiber)
„ Pre:Post = 1:3
„ Ganglionic transmission is the same as
sympathetic nervous system
„
Cranosacral
outflow
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Parasympathetic:
Neurotransmission
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Cholinergic receptors
„ มี 2 ชนิดคือ
„
Nicotinic receptor
„
„
„
„
Muscarinic receptors
„
„
„
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เปน ionotropic receptor
ยอมให Na+ และ K+ แพรผา นได
พบที่ postganglionic neurons ของทั้งระบบประสาท
sympathetic และ parasympathetic
เปน metabotropic receptor
G protein-coupled
มี 5 subtypes M1-M5
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Muscarinic receptors:
M2, M4
Muscarinic cholinergic receptors
M1
Second
messenger
IP3
DAG
Distribution
Ganglia
Neuron
CNS
M2
M3
M4
M5
↓cAMP
IP3
DAG
↓cAMP
IP3
DAG
Smooth
muscle
Glands
CNS
CNS
Open K+
channel
Heart
Ganglia
Agonist
Muscarine
Antagonist
Atropine
„ Decrease cAMP
„ Opening of K+ channels
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Amanita muscaria
Muscarinic receptors:
M1. M3, M5
Parasympathetic responses
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Autonomic control:
Eyes
Sympathetic
•Radial muscle of iris
•Ciliary muscle
Parasympathetic
•Circular muscle of iris
•Ciliary muscle
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Autonomic control:
Heart
contraction (α1)
Relaxation (β)
Midriasis
Far vision
contraction (M3)
contraction (M3)
Miosis
near vision 35
Sympathetic
•SA nodes
•Cardiac muscle
Parasympathetic
•SA nodes
•Cardiac muscle
increase heart rate (β1)
increase contractility (β1)
decrease heart rate (M2)
decrease contractility (M2)
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Autonomic control:
Vascular and airway smooth muscle
Autonomic control:
GI smooth muscle
„ Vasular smooth muscle
„ Sympathetic
„ Skin, splanchnic vessels
Contraction (α1)
„ vessels in skeletal muscle
Relaxation (Muscarinic)
„ Parasympathetic
„ Endothelial cells
Release EDRF (M3)
(EDRF=endothelial derived relaxing factorÎvessel relax)
„ Sympathetic
„ GI smooth muscle
„ GI sphincter
Relaxation (β2)
Contraction (α1)
„ Parasympathetic
„ GI smooth muscle
„ GI sphincter
Contraction (M3)
Relaxation
„ Airway smooth muscle
„ Sympathetic
„ Parasympathetic
Relaxation (β1)
Contraction (M3)
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Autonomic control:
Genitourinary
Sympathetic
Relaxes
Bladder Wall
β2
Contracts α1
Sphincter
Relaxes
Uterus, Pregnant
β2
Contracts α
Pennis, Seminal vesicles Ejaculation α
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Autonomic control:
Micturation reflex
Parasympathetic
Contracts
M3
Relaxes
Contracts
Erection
M3
M
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Autonomic control:
Others
Enteric nervous system (ENS)
„ Glands (salivary, GI, lacrimal)
„ Sympathetic
Decrease secretion
„ Parasympathetic
Increase secretion
„ Endocrine
„ Sympathetic
„ Kidney
„ Pancreatic β cell
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„ จัดเปนระบบประสาทอัตโนวัติระบบที่สาม
„ ประกอบดวยจํานวนเซลลประสาท 80-100 ลานเซลล
„ ประกอบดวยทั้ง sensory และ motor neuron
„ จัดเรียงเปน network ของ ganglia ขนาดเล็กเปนรางแหอยูในผนังลําไส
increase renin release
decrease insulin secretion
„
„ Metabolic functions
„ Sympathetic
„ Liver
increase gluconeogenesis/glycogenolysis
„ Fat
increase lipolysis
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Myenteric (Auerbach’s) plexus ระหวางชั้นกลามเนื้อ
„
„
„
ควบคุมการเคลื่อนไหว (peristalsis)
ควบคุมการคัดหลั่งสารจาก submucosal glands
Submucosal (Meissner’s) plexus ใน submucosa
„
ควบคุม submucosal vessels and glands
42
Enteric nervous system:
Structure
Enteric nervous system:
Pathway
Serotonin receptor
antagonist:
Ondansetron
43
Enteric nervous system:
Peristalsis
44
Enteric nervous system:
Neurotransmitters
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Higher control of ANS
Horner’s syndrome
„ Ptosis
„ Central autonomic network: Coordination of
autonomic functions
„
„ Miosis
„ Endopthalmos
Brainstem:
„
„
„
„
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„ Anhydrosis
nucleus tractus solutarius
Medullary reticular formation
Parabrachial nucleus
Periaqueductal gray
Hypothalamus
„ Thalamus
„ Forebrain and Amydaloid complex
„
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„ Cancer involve upper part of 48lung
Diabetic neuropathy
Autonomic failure
„ Diabetic ulcer
„ Malfunction of the ANS resulted from an imbalance
between the sympathetic and parasympathetic
divisions.
„ Diabetic neuropathy
„ Dizziness or lightheaded
„ Aging, DM, stroke and Parkinson's disease
„ a drop in blood pressure when a person is
„ Dizziness or lightheaded
standing or stands up suddenly (orthostatic
hypotension)
„ The most common signs of ANS impairment are
„
a drop in blood pressure when a person is standing
or stands up suddenly (orthostatic hypotension) or
„
a drop in blood pressure within one hour of eating a
meal (postprandial hypotension).
„ a drop in blood pressure within one hour of
eating a meal (postprandial hypotension).
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Questions ?
„ ระบบประสาทอัตโนวัติคืออะไร
„ ระบบประสาทอัตโนวัติมีความสําคัญอยางไร
„ องคประกอบของระบบประสาทอัตโนวัติมีอะไรบาง มีการทํางานอยางไร
„ ระบบประสาทอัตโนวัติมีกี่ระบบ อะไรบาง ทําหนาที่สําคัญอะไรบาง แตละ
ระบบมีองคประกอบอะไรบาง
„ ระบบประสาท sympathetic
„ ระบบประสาท Parasympathetic
„ ระบบประสาท Enteric
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