potensial aksi
TRANSCRIPT
POTENSIAL AKSI
Oleh :
Drg. Berlian Bidarisugma
NERVOUS SYSTEM
Peripheral NS :Nn. CranialisNn. Spinalis
Central NS :Otak &Medulla spinalis
Autonomic NS :Sympathetic NS
Parasympathetic NS
Excitable cell
Neuron Myocyte = Muscle cell
Neuron
Signal transduction
Message / stimulus / substance / Hormone / Cytokine / Zat
RECEPTOR first messenger
(membrane cell / organells )
Bahan / substant : second messenger
Characteristic excitability tissue
Stimulus
Neurolemma = membrane cell of neuron
Action Potential
conduction
Ions for action potential
1. Natrium
channel : open n close rapidly
2. Kalium
channel : open n close slowly
- 70 mV
+30 mV
- 55 mV
- 0 mV
Firing level
repolarization
depolarization
Action potential
Overshoot
ACTION POTENTIAL
1.Stimulus
2.Cannel Na+ open : Na+ influx
3.Depolarization
4.Channel Na+ close
5.Cl- influx : first repolarization
6.Channel K+ open : K+ efflux
7.Repolarization
Na+
gate
Closed
Na+
Na+
Opened
Voltage – gated sodium channels
amyelin axon
+ +
+
+ +
- --
- -
Potensial aksi
Action Potential
Node of Ranvier
Saltatory conduction
myelin axon
Schwann cell
neuroglia – type : oligodendrocyte
Function : - Protect for neuron- Form myelin sheath
Firing level
Time
Potensial Lokal
NA
0mVolt
Summasi
Potensial aksi
Types of stimulus
1.Subliminal : local potential
2.Liminal : action potential
3.Supraliminal : sda
Action potential
1. Follow ‘All or None’2. Propagation 3. No summasi
Local potential
1. No ‘All or None’2. No propagation 3. summasi
Summasi
Potensial aksi
Potensial lokal
Axon
Propagation
Action potential
Hipopolarisasi
mvolt
- 55
- 70
Firing level
RMP
Hiperpolarisasi
Na+
Na+
Na+
+Bgate
Opened
Closed
SELAMAT BELAJAR