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SEKOLAH TINGGI ILMU KESEHATAN KOTA SUKABUMI
Program Study S1 Keperawatan
https://stikeskotasukabumi.wordpress.com
NERVOUS SYSTEM
PERIPHERAL NERVOUS SYTEM
CENTRAL NERVOUS SYETM
MOTOR
DIVISION
SENSORY
DIVISION
AUTONOMIC
SYSTEM
SOMATIC
SYSTEM
Sympathetic
Parasympathetic
Organization of Nervous System
BRAIN SPINAL
CORD
PERIPHERAL NERVOUS SYSTEM (PNS)
Sensory neuron Motor neuron
Somatic motor neuron
Autonomic motor neuron
Innervate smooth muscle, cardiac muscle, and gland
Innervate skeletal muscle
Anatomical diff …
Spinal cord
Spinal cord
Somatic motor neuron
Preganglionic neuron
Postganglionic neuron
Skeletal muscle
Effector organ e.g. smooth muscle, heart, or gland
Autonomic ganglion
Somatic motor neuron
Autonomic motor neuron
ORGANIZATION OF SNS AND ANS
PERIPHERAL …….
Anterior horn
Lateral horn
1. CONTRASTING THE SOMATIC AND THE AUTONOMIC NERVEOUS SYSTEMS
Anatomical differences between Somatic Nervous System and Autonomic Nervous Syatem
Somatic Nervous System
Autonomic Nervous System
Cell body in CNS
Cell body (Ganglion) out of CNS
Effectors
Preganglionic neuron
Postganglionic neuron
Somatic neuron
Functional differences between Somatic Nervous System and Autonomic Nervous System
Somatic Nervous System Autonomic Nervous System
1. Conscious2. Always excitatory
1. Unconscious2. Excitatory and inhibitory (during
meal ANS stimulate the stomach activities, during exercise inhibit)
Summarizes of differences…………
Comparison of the Somatic and Autonomic Nervous Systems
Feature SNS ANS
Target tissues Skeletal muscle Smooth, cardiac muscle, and glands
Regulation Controls all conscious and unconscious movement of skeletal muscle
Unconscious regulation, although influenced by conscious mental function
Response to stimulation Skeletal muscle contract Target tissues are stimulated or inhibited
Neuron arrangement One neuron extends from the CNS to skeletal muscle
Two neuron in series, the preganglioni from CNS to ganglion, postganglion from ganglion to effectors
Neuron cell body location
Neuron cell bodies are in motor nuclei of the cranial nerves and in the ventral horn of the spinal cord
Pregangiolonic neuron cell bodies are in autonomic nuclei of the cranial nerves and in the lateral part of the spinal cord; postganglionic neuron cell bodies are in the autonomic ganglia
Continued …………
Comparison of the Somatic and Autonomic Nervous Systems
Feature SNS ANS
Number of synapses One synapse between the somatic motor neuron and the skeletal muscle
Two synapses; first in autonomic ganglia; second is at the target tissues
Axon sheaths Myelinated Preganglionic are myelinated; postganglionic are unmyelinated
Neurotransmitter substances
Acetylcholine Acetylcholine is released by preganglionic neurons; either acetylcholine and norepinephrine is released by postganglionic neurons
Receptor molecules Receptor molecules for acetylcholine are nicotinic
In autonomic ganglia, receptor molecules for acetylcholine are nicotinic; in target tissues, receptor for acetylcholine are muscarinic, for norepinephrine are α or β - adrenergic
Organization of somatic and autonomic nervous syetem ……
2. ANATOMY OF THE AUTONOMIS NERVOUS SYSTEM
ANS
SYMPATHETIC PARASYMPATHETIC
ENTERIC NERVOUS SYSTEM
Complex network of neuron cell bodies and axons within the wall of digestive tract that composed of sympathetic and parasympathetic
SYMPATHETIC DIVISION
1. Neuron cell bodies located in the lateral horn spinal cord gray matter between T1 and L2 segments called thoracolumbar division
2. The preganglionic neuron project to autonomic ganglia (sympathetic chain ganglia = paravertebral ganglia) on either side of vertebral column behind the parietal pleural
3. The sympathetic chain extends into cervical and sacral regions but only ganglia from T1 – L2 that receive preganglionic axons. The cervical and sacral regions is associated with the nearly every pair of spinal nerves
4. The cervical ganglia fuse during fetal development only two or three pairs exist in the adult
5. The preganglionic neuron are small and myelinated
6. The short connection between spinal nerve and a ganglion called white ramus communicants
SYMPATHETIC DIVISION
Preganglionic neuron cell bodies in the lateral horn between T1-S2 Thoracolumbar divison
Sympathetic chain ganglia = paravertebral ganglia
THE ROUTES TAKEN BY SYMPATHETIC AXONS
THE ROUTES TAKEN BY SYMPATHETIC AXONS……….
PARASYMPATHETIC DIVISION
The cell bodies are within the brainstem and sacral region
Craniosacral division
III
VII
IX
X
Comparison of the Sympathetic and Parasympathetic Division
Feature Sympathetic division Parasympathetic division
Location of preganglionic cell Bodies
Lateral horns of spinal cord gray matter (T1 – L2)
Brainstem and lateral parts of spinal gray matter (S2 – S4)
Outflow from the CNS Spinal nervesSympathetic nervesSplanchnic nerves
Cranial nervesPelvic nerves
Ganglia The chain along spinal cord for spinal and sympathetic nerves; collateral ganglia for splanchnic nerves
Terminal ganglia near or on effector organ
Number of postganglionic neurons for each preganglionic neuron
Many (much divergence) Few (less divergence)
Relative length of neuron Short preganglionicLong postganglionic
Long preganglionicShort postganglionic
ENTERIC NERVOUS SYSTEM
1. Consist of nerve plexuses within the wall of the digestive tract
2. The plexuses have contributions from three sources:
a. Sensory neurons that connect the digestive tract to the CNS
b. ANS motor neurons that connect the CNS to the digestive tract
c. Enteric neurons, which are confined to the enteric plexus
3. The CNS is capable of monitoring the digestive tract through sensory neurons and controlling its smooth muscle and gland through ANS motor neurons
TYPE OF ENTERIC NEURON
1. Enteric sensory neurons, detect chemical composition and wall stretching.
2. Enteric motor neurons, stimulate or inhibit smooth muscle contraction and gland secretion
3. Enteric interneurons, connect sensory and motor neurons to each other.
THE DISTRIBUTION OF AUTONOMIC NERVE FIBERS
1. Sympathetic division
a. Sympathetic axons from ganglia to target tissues pass through spinal, sympathetic, and splanchnic nerves, head and neck nerve plexuses, thoracic nerve plexuses, and abdominopelvic nerve plexuses
b. Sympathetic and splanchnic nerves join autonomic nerve plexus, complex, interconnected neural network formed by neurons of sympathetic and parasympathetic division. They are named according to organs they supply (cardiac plexus) or to blood vessels along which they are found (thoracic aortic plexus).
2. Parasympathetic division
a. Parasympathetic outflow is through cranial nerve (III, VII, IX, X), and plexuses (vagus and thoracic nerve plexuses, abdominal nerve plexuses, and plevic nerve and pelvic nerve plexuses
SENSORY NEURONS IN AUTONOMIC PLEXUSES
a. Not strictly part of autonomic nervous system
b. Some are part of reflex arcs regulating organ activities.
c. Transmit pain and pressure sensations from organ to CNS
d. The cell bodies of these sensory neuron are found in the dorsal root ganglia and in certain cranial nerve (which are swelling on nerves close to their attachment to the brain)
3. PHYSIOLOGY OF THE ANS
Neurotransmitters
Sympathetic Parasympathetic
Acetylcholine
Norepinephrine
Ganglion
Preganglion (cholinergic)
Postganglion (adrenergic)
Postganglion (Cholinergic)
Receptors
Cholinergic receptor(binds to acetylcholine)
Adrenergic receptor(binds to norepinephrine)
Nicotinic Bind to nicotin (tobacco
alkaloid)Muscarinic
Bind to muscarine (alkaloid poisonous mushroom)
Alpha receptor
α1 stimulatory response
α2 inhibitory response
Beta receptor
β1 various response
β2 various response
Nicotine does not bind the muscarinic receptor
Muscarine does not bind to nicotinic receptor
Actylcholine binds other the nicotinic or muscarinic receptor
Location of ANS receptors
Sympathetic division
Most target tissues have adrenergic receptors
Sympathetic division
Some target tissues have muscarinic receptor
Sweat gland
Parasympathetic division
Effects and receptor types of sympathetic and parasympathetic division on various tissues
Organ Sympathetic effects and receptor types Parasympathetic effects and receptors types
Adipose tissue Fat breakdown release of fatty acids (α2 and β1) None
Arrector pili muscle Contrastion (α1) None
Blood (platelets) Increase coagulation None
Blood vessels (arterioles):Digestive organHeartKidneysLungsSkeletal muscleSkinBlood vessels (veins)
Constriction (α1)
Dilatation (β2), constriction (α1)
Constriction (α1 & 2); dilatation (β1&2)
Dilatation (β2); constriction (α1)
Dilatation (β2); constriction (α1)
Constriction (α1 & 2)
Constriction (α1 & 2); dilataion (β2)
NoneNoneNoneNoneNoneNone
Effects ………………continue
Organ Sympathetic effects and receptor types Parasympathetic effects and receptors types
EyeCiliary musclePupil
Relaxation for far vision (β2)
Dilated (α1)
Constriction for near vision (m)Constricted (m)
Gallbladder Relaxation (β2) Constriction (m)
GlandsAdrenalGastricLacrimalPancreas
Salivary
Sweat• Apocrine• Merocrine
Release of epinephrine & norepinephrin (n)
Decrease gastric secretion (α2)
Slight tear production (α)
Decrease insulin secretion (α2)
Decrease exocrine secretion (α)
Blood vessel constriction; produce thick and viscous saliva
Thick, organic secretion (m)Watery sweat from most of the skin (m); sweat from palms and soles (α1)
NoneIncrease gastric secretion (m)Increase tear secretion (m)Increase insulin secretion (m)Increase exocrine secretion (m)Blood vessels dilation ; produce thin and copious saliva (m)
NoneNone
Continue ………….
Organ Sympathetic effects and receptor types Parasympathetic effects and receptors types
Heart Increases rate and force of contraction (β2 & β2) Decreases rate (m)
Liver Glucose released into blood (α1 & β2) None
Lungs Dilates air passageways (β2) Constricts airpassageways (m)
Metabolism Increases up to 100% (α & β) None
Sex organs Ejacutaion (α1); erection Erection (m)
Skeletal muscle Breakdown glycogen to glucose (β2) None
Stomach and intestines•Wall•Sphincter
Decreases tone (α1, α2 & β2)
Increases tone (α1)
Increases motility (m)Decreases tone (m)
Urinary baldder•Wall (detrusor)•Neck of bladder•Internal urinary spihincter
None
Contraction (α1)
Contraction (α1)
Contraction (m)Relaxation (m)Relaxation (m)
4. REGULATION OF THE ANS
1. To maintain homeostasis, the structures innervated by ANS are regulated through the autonomic reflexes
2. Input come from cerebrum, hypothalamus, and other area as conscious thoughts and actions, emotions, and other CNS activities
a. Parasympathetic reflex
b. Sympathetic reflex
c. Influence of higher part of the brain on autonomic functions
Thought and emotion influence ANS through hypothalamus
ANS integrating center that interact with cerebrum, limbic system, brainstem, spinal cord; also regulate the body temperatureANS reflex centers for controlling pupil size, accommodation, tear production, salivation, coughing, swallowing, digestive activities, blood vessels diameter, and respiration
ANS reflex centers for regulating defecation, urination, penile and clitoral erection, and ejaculation
Functions at rest versus activity
Sympathetic division influences under active or stress condition referred to “flight – or fight response”
Parasympathetic division influences under resting condition
During exercise
1. Increases heart rate and force of contraction; increase blood pressure and movement
2. Oxygen, nutrient consumption, waste product are increased
3. Blood flow into tissue increase; reduces blood flow into tissues not involve in exercise by vasoconstriction making blood more available for the exercising tissues
4. Dilatation of air passageway
5. Increases the availability of energy sources. Muscle and liver stimulated to break down glycogen into glucose
6. Exercising muscle generate heat, body temperature increase
7. The activity of organs not essential for exercise decrease
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