NEUROLOGI - KBK RAHMAN

8/7/2019 NEUROLOGI - KBK RAHMAN

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SISTEM SARAFSISTEM SARAF

Dr. H.Abd Rachman Tanjung AIFM

BAGIAN FISIOLOGI

FAKULTAS KEDOKTERN UISU


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SISTEM SYARAF

----- > sistem yang mengatur dan

mengendalikan semua kegiatanaktifitas tubuh seperti berjalan,

menggerakkan tangan, mengunyah

dsb.


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SISTEM SARAFSISTEM SARAF

Informasi lingkungan dlm dan luar SSP

melalui berbagai reseptor sensorik

Reseptor mrpk transducer merubah

berbagai btk energi potensial aksi di

dalam neuron

Reseptor mrpk bgn dr satu neuron atau

sel potensial aksi di dalam neuron

Mis: mekanis (touch, pressure); termis

(degree warm); electromagnetic (light);

chemical (taste, odor,O2drh)


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Nervous SystemNervous System

A complex array of specializedstructures which serve to:

Receive Store

Transmit information

Consist of the CNS and the PNS Neuron- basic unit of the NS

1 trillion neurons


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NeuronsNeurons

Made up of dendrites

Soma

Axon- axon terminal Has different organelles but no

centromere

Classification according to

1. structure

2. Form

3. covering Schwann cells


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NeuronsNeurons


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PropertiesofNerve FibersPropertiesofNerve Fibers

1. Excitability

2. Conductivity


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MyelinatedMyelinated FibersFibers

Schwann cells

Nodes of Ranvier Saltatory Conduction

Advantages

faster conduction

saves energy

less loss of ions


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MyelinatedMyelinated FibersFibers


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ActionPotentialActionPotential


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Synapseand SynapticSynapseand Synaptic

TransmissionTransmission

Synapse

an anatomically specialized junction

between two neurons

important in the transport of nerve

signals from one neuron (presynaptic) to

the next neuron (postsynaptic)

100 quadrillon synapses in the CNS 2 types

a. Electrical

b. Chemical


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PresynapticPresynaptic andPostsynapticandPostsynaptic

NeuronNeuron

Presynaptic neuron

has lots of mitochondria

has NTs inside vesicles

usual forms are ; round, dense, flat andsphenoid

intertwining cerebellum

basket and climbing midbrain

Postsynaptic neuron

contains the receptor proteins


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PresynapticPresynaptic andPostsynapticandPostsynaptic

NeuronNeuron

Presynaptic

Postsynaptic


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ClassesofNeurotransmittersClassesofNeurotransmitters

1. Acetylcholine

2. Biogenic amines catecholamines,

serotonin, histamine

3. Amino acids glutamate, GABA

4. Neuropeptides endogenous opioids

5. Miscellaneous nitric acid,

adenosine


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Factors Affecting SynapticFactors Affecting Synaptic


1. acid-base states

a. alkalosis

b. acidosis2. oxygen and CO2 concentrations

Drugs those that excite

those that inhibit


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Neuromuscular JunctionandNeuromuscular Junctionand

NN--M TransmissionM Transmission


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FactorsaffectingNMFactorsaffectingNM


1. Ions

2. Drugs curare, antibiotics3. Acid base conditions

4. Temperature


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SISTEM REFLEXSISTEM REFLEX

PADA MANUSIAPADA MANUSIA


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Motor Funct onso theMotor Funct onso the

SpinalCord;theCordSpinalCord;theCord

ReflexesReflexes

Sensory information is integrated at alllevels of the nervous system and causes

appropriate motor response beginning in

the spinal cord with simple muscle reflexes


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REFLEXESREFLEXES

Reflex Arc basic unit of integrated reflexactivity

Components:

1. Sense Organ 3. Synapse2. Afferent Neurons 4.Efferent neuron

5. Effector


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TypesofReflex Arc andTypesofReflex Arc and

ReflexesoccurringinthemReflexesoccurringinthem

1. Monosynaptic one with a singlesynapse between the afferent andefferent neurons

o Monosynaptic Reflexes StretchReflex

When a muscle with an intact nerve

supply is stretched, it contractsClinical Examples of Stretch Reflex

a. Knee jerk or patellar reflex

b. Ankle jerk


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2. Polysynaptic one or more interneurons are

interposed between afferent and efferent

neurons Polysynaptic Reflexes

Clinical Examples:

a.Withdrawal reflex

b. Crossed-extensor reflex

c. Abdominal reflex

d. Cremasteric reflex


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Withdrawal Reflex typical polysynaptic reflexthat occurs in response to a noxious and usuallypainful stimulation of the skin or subcutaneoustissues and muscle. The response is flexor musclecontraction and inhibition of extensor muscle

Crossed Extensor Response part of withdrawalreflex. When a strong stimulus is applied to alimb, the response include not only flexion andwithdrawal of the limb but also extension of theopposite limb


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Importanceo WthdrawalImportanceo Wthdrawal

ReflexReflex

The stimuli are called nociceptive

stimuli (noxious or harmful)

Flexion of the stimulated limb gets it

away from the source of irritation and

extension of the of the limb supports

the body


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Human reflexes

Tendon reflexesThe deep tendon reflexes provide information on the integrity of the

central and peripheral nervous system. Generally, decreased reflexes

indicate a peripheral problem, and lively or exaggerated reflexes a

central one.Biceps reflex (C5, C6)

Brachioradialis reflex (C5, C6, C7)

Extensor digitorum reflex (C6, C7)

Triceps reflex (C6, C7, C8)

Patellar reflex or knee-jerk reflex (L2, L3, L4)

Ankle jerk reflex (Achilles reflex) (S1, S2)Plantar reflex or Babinski reflex (L5, S1, S2)

While the reflexes above are stimulated mechanically, the term H-

reflex refers to the analogous reflex stimulated electrically, and Tonic

vibration reflex for those stimulated by vibration.


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Grading

Grade Description

0 Absent1+ or + Hypoactive

2+ or ++ "Normal"

3+ or +++ Hyperactive without clonus4+ or ++++ Hyperactive with clonus

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