chapter 33 regulation of the visceral function by the nervous system
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Chapter 33 Regulation of the Visceral Function by the Nervous System. I Autonomic Nervous System 1. Basic of the Anatomy. Autonomic Nervous System. Including parasympathetic, sympathetic, and enteric divisions. - PowerPoint PPT PresentationTRANSCRIPT
Chapter 33
Regulation of the Visceral Function by the Nervous System
I Autonomic Nervous SystemI Autonomic Nervous System
1. Basic of the Anatomy1. Basic of the Anatomy
Autonomic Nervous SystemAutonomic Nervous System
Including parasympathetic, sympathetic, and enteric divisions.
Coordinates cardiovascular, respiratory, digestive, excretory and reproductive systems.
The enteric system is essentially an independent nervous system responsible for regulation of digestive functions.
Somatic and Autonomic Nervous System
Somatic and Autonomic Somatic and Autonomic Nervous SystemNervous System
Somatic Skeletal muscle Conscious and
unconscious movement Skeletal muscle contracts One synapse Acetylcholine
Autonomic Smooth and cardiac
muscle and glands Unconscious regulation Target tissues stimulated
or inhibited Two synapses Acetycholine by
preganglionic neurons and ACh or norepinephrine by postganglionic neurons
Preganglionic cell bodies in lateral horns of spinal cord T1-L2
Sympathetic Division
侧副神经节
Parasympathetic DivisionParasympathetic Division
Preganglionic cell bodies in nuclei of brainstem or lateral parts of spinal cord ( S2-S4)– Preganglionic axons
from brain pass to ganglia through cranial nerves
– Preganglionic axons from sacral region pass through pelvic nerves to ganglia
Preganglionic axons pass to ganglia within wall of or near organ innervated
Parasympathetic Parasympathetic and sympathetic and sympathetic
nerve nerve distributiondistribution
2. Neurotransmitters and 2. Neurotransmitters and NeuroreceptorsNeuroreceptors
Acetylcholine and Norepinephrine
All preganglionic neurons are cholinergic
Parasympathetic post ganglionic neurons are cholinergic
Sympathetic post ganglionic neurons are adrenergic except
– Sympathetics innervating sweat glands, blood vessels in skeletal muscle, and piloerection muscles are cholinergic
NeurotransmittersNeurotransmitters
ACh AChSweatglands
Striatedmuscle
AChSOMATIC NERVOUS SYSTEM
HeartSm. mus.Glands
ACh AChParasympathetic
ACh E, NE
Ad. M.
HeartSm. mus.Glands
ACh NE
AUTONOMIC NERVOUS SYSTEM
Sympathetic
AcetylcholineAcetylcholine
Nicotinic receptors– Nm (muscular-type or N2): skeletal muscle
– Nn (neuron-type, or N1): autonomic ganglia, CNS
Muscarinic receptors– Postganglionic parasympathetic and a few
sympathetic sites, CNS
– Receptor subtypes: M1-5
CatecholaminesCatecholamines Norepinephrine
– Postganglionic sympathetic, CNS, adrenal medulla– Receptors: 1, 2, 1
Epinephrine– Adrenal medulla, CNS– Receptors: 1, 2, 1 , 2
Dopamine– Autonomic ganglia, CNS– Receptors: D(1-5), 1, 1
Location of ANS ReceptorsLocation of ANS Receptors
3 Function of the Sympathetic and Parasympathetic Nerve
Properties of the ANSProperties of the ANSTonic dischargeDouble innervation
– Most blood vessels are innervated only by sympathetic nerves.
– Parasympathetic activity dominates the heart and GI tract.
Dependent on the states of the target organDifferent physiological significance
– Sympathetic nerve: fight and flight reaction– Parasympathetic nerve: Wind down, relaxation, digestion
SNSSNS
Sympathetic nervous system prototypically “fight” or “flight”.
Associated with increased
energy expenditure,
cardiopulmonary adjustments for intense activity,
blood flow adjustments for maximum energy expenditure.
SNS - SNS - Fight & Flight ReactionFight & Flight Reaction
You’re walking alone at night and all the sudden you hear an unfamiliar noise near by… In a matter of seconds,
your heart rate increases dramatically, blood vessels in your skeletal muscles dilate, blood vessels in the visceral muscles constrict, digestion is ceased, your liver ramps up glucose release, your pupils dilate, salivary production decreases, sweat increases.
Parasympathetic Nervous Parasympathetic Nervous SystemSystem
If that noise turns out to be the result of wind,
the body is returned to “pre-noise” state.This is the job of the parasympathetic
nervous system.
Autonomic Nervous System• Parasympathicus• Wind down,
relaxation, digestion• Dominated by
Acetylcholine
• Sympathicus • Fight & Flight
Reaction• Dominated by
Noradrenaline (Adrenaline)
• Fear, exercise, rage
1. Spinal cord
bladder and rectum reflex (micturition and defecation)
the baroreceptor reflex
sweating of the skin
II. Central Regulation of Visceral Function
2. Medulla oblongata
Vital (respiratory and cardiovascular) center:
Other autonomic reflexes:
Swallow, cough, sneeze, gag, and vomit.
Tu :19.17
3. Hypothalamus
Hypothalamic FunctionsHypothalamic Functions Food Intake Water Balance Sleep/wake cycle Emotions and behavior Circadian Endocrine Functions Body Temperature Autonomic Nervous System
Food IntakeFood Intake Ventromedial and Paraventricular Nuclei are satiety centers
– Lesion causes obesity– Through disrupting satiety input to the periventricular nucleus
Lateral HT is feeding center – Stimulation cause food and water intake– Lesion causes starvation behavior– Through damage the medial forebrain bundle, leading to neglect syndrome – no motivation
to eat
Water BalanceWater Balance
Thirst center in the hypothalamus (supraotic nucleus) is stimulated by:– Cellular dehydration– Decreased salivary production– Increased blood osmotic pressure– Decreased blood volume
Thirst center response– Release vasopressin– Cause sensation of thirst
Sleep/Wake CycleSleep/Wake Cycle
suprachiasmatic nuc is biological clock
preoptic nuc can initiate sleep
lateral hypothalamus can change cortical arousal
post hypothalamus lesion can cause coma or impaired
arousal
Emotions and BehaviorEmotions and Behavior
Ventromedial lesions can cause viciousness/rage
Posterior HT stimulates sympathetic functions
Anterior HT stimulates parasympathetic functions
Mamillary nuclei recent memory
Almost all land animals coordinate their behavior
according to circadian rhythms
Suprachiasmatic Nuclei (SCN)
Circadian
Circadian Rhythms of Physiological Functions
Endocrine FunctionEndocrine Function
Regulation of Adenohypophysis
Secretion of Hormones (Vasopressin and Oxytocin)
Functions of the Functions of the HypothalamusHypothalamus
Food intakeWater balanceSleep/wake cycleEmotions and behaviorCircadianEndocrine FunctionBody temperatureAutonomic Nervous System
4 Influence of Brain on 4 Influence of Brain on Autonomic FunctionsAutonomic Functions
III Function of Sympathetic and Parasympathetic nerve on the target organs
Physiology Physiology (Table 5-1)(Table 5-1)
Effector Sympathetic ParasympatheticRadialmuscle
Contraction(mydriasis, 1)
—
Sphinctor — Contraction(miosis)
Ciliarymuscle
Slight relaxa-tion (2)
Contraction (nearvision)
Eye
Cornea
Lens
Ciliary muscle
Iris
SA node
Atria
AV node
Ventricles
Heart
Effector Sympathetic ParasympatheticSA node Tachycardia
(1,2)Bradycardia
Atria contractilityand conduction(1,2)
contractility, conduction(usually)
AV node conductionand auto-maticity (1,2)
conduction
Ventricles contractility,conduction, andautomaticity(1,2,1)
—
Effector Sympathetic ParasympatheticSkin andmucosa
Constriction(1,2)
Dilation (?)
Skeletalmuscle
Constriction(), dilation(2)
—
Salivaryglands
Constriction(1,2)
Dilation
Erectiletissue
Constriction()
Dilation
Blood vessels
Effector Sympathetic ParasympatheticBronchialsm. musc.
Relaxation (2) Constriction
Bronchialglands
(1), (2),secretion
secretion
Salivaryglands
Viscous,amylasesecretion(1,1,2)
Profuse waterysecretion
Lungs and salivary glands
Effector Sympathetic ParasympatheticSmoothmuscle
motility andtone(1,2,1,2)
motility andtone
Sphincters Contraction(1)
Relaxation
Secretions secretion (2) secretionLiver Glycogenolysis,
gluconeogene-sis (1,2)
Glycogensynthesis
Gastrointestinal tract and liver