Qhov sib txawv tseem ceeb ntawm axon hillock thiab thawj ntu yog tias axon hillock yog tam sim no nyob rau hauv lub cell lub cev ntawm lub neuron thaum lub sij hawm thawj zaug nyob rau hauv lub proximal ib feem ntawm lub axon ntawm lub neuron.
Neurons lossis paj hlwb yog lub luag haujlwm rau kev xa cov ntaub ntawv mus rau lwm lub hlwb, cov leeg, thiab cov qog hlwb. Ib qho axon yog ib feem ntawm cov neuron uas nqa cov hlab ntsha impulses tawm ntawm lub cev ntawm tes. Nws yog qhov ntev, slender projection uas ua rau hluav taws xob impulses hu ua kev ua kom muaj peev xwm deb ntawm cov neuron. Axons yog cov kab sib kis tseem ceeb hauv lub paj hlwb. Cov cheeb tsam axonal suav nrog axon hillock, thawj ntu, seem ntawm axon, axon telodendria, thiab axon terminals. Axon hillock thiab thawj ntu nyob rau hauv cov neuron ua lub luag haujlwm tseem ceeb hauv kev ua cov paj hlwb.
Axon Hillock yog dab tsi?
Lub axon hillock yog ib feem tshwj xeeb ntawm lub cev ntawm lub cev ntawm cov neuron uas txuas rau axon. Lub axon tshwm sim los ntawm lub cev ntawm tes ntawm qhov siab me me hu ua axon hillock. Nws muaj ntau yam khoom tshwj xeeb uas pab tsim kom muaj peev xwm ua tau. Ib qho axon hillock ntawm axon muaj kwv yees li 100-200 voltage-gated sodium channels ib square micrometer. Axon hillock feem ntau pom nyob rau hauv lub teeb tsom iav los ntawm nws cov tsos thiab qhov chaw nyob hauv lub neuron. Nws tseem yog qhov chaw kawg uas cov membrane muaj peev xwm nthuav tawm los ntawm synaptic inputs hauv lub cev ntawm tes ua ntej lawv xa mus rau axon. Ib qho axon hillock kuj tseem cais cov txheej txheem ntawm lub cev ntawm lub cev thiab axon. Qhov no tso cai rau qhov chaw ntawm daim nyias nyias nyias mus rau sab axonal lossis ntawm lub cev ntawm tes.
Daim duab 01: Axon Hillock
Axon hillock suav txog qhov inhibitory postsynaptic peev xwm (IPSPs) thiab excitatory postsynaptic peev xwm (EPSPs). Raws li qhov tshwm sim, qhov pib tshwm sim tau dhau mus, thiab qhov kev ua tau zoo tau nthuav tawm los ntawm tus so ntawm axon. Kev tshwm sim tshwm sim vim muaj kev tawm tswv yim zoo ntawm cov neeg coob coob ntawm cov kab hluav taws xob gated sodium raws tam sim no ntawm axon hillock nrog qhov ceev tseem ceeb. Thaum qhov pib ua haujlwm muaj peev xwm pib ntawm axon hillock, nws propagates hauv axon. Thaum lub sij hawm depolarization, cov presynaptic neurons tso tawm excitatory neurotransmitters thiab khi rau postsynaptic dendritic spines. Qhov no qhib cov ligan-gated ion channels, thiab sodium ions nkag mus rau hauv lub cell. Qhov no ua rau postsynaptic membrane depolarized, thiab depolarization mus rau axon hillock. Yog tias qhov xwm txheej no rov ua dua nyob rau lub sijhawm luv luv, axon hillock yog depolarized txaus los qhib qhov hluav taws xob-gated sodium channels. Qhov no ua rau pib muaj peev xwm ua tau thiab nthuav tawm hauv axon.
Dab tsi yog Ib Ntu Pib?
ntu ntu yog ib feem ntawm axon nyob rau ntawm qhov kawg. Nws muaj qhov ntom ntom ntom ntawm voltage-gated ion channel. Nws yog qhov chaw ntawm kev nqis tes ua muaj peev xwm pib thiab muaj ntau cov tshuaj sodium thiab potassium raws piv rau lwm cov tshuaj membrane. Thawj ntu cais cov somatodendritic compartment los ntawm axon.
Lub luag haujlwm tseem ceeb ntawm ntu thawj zaug yog kev sib koom ua ke thiab tswj cov ion channel nyob rau hauv siab ceev kom pib muaj peev xwm ua haujlwm thiab tswj hwm cov polarity ntawm neuronal los ntawm kev tswj hwm kev faib tawm thiab kev lag luam ntawm cov protein, organelles, vesicles, thiab lipids ntawm axonal thiab somatodendritic compartments. Thawj ntu yog unmyelinated thiab muaj cov protein complexes tshwj xeeb. Lub ntsiab scaffolding protein uas yog lub luag hauj lwm rau anchoring ntawm ion channel nyob rau hauv thawj ntu yog Ankyrin G (AnkG). Qhov tsis tuaj los yog poob ntawm AnkG ua rau lub disassembly ntawm nws cov qauv. AnkG yog ib qho ntawm cov protein tseem ceeb koom nrog hauv kev tsim cov ntu thawj zaug. Txoj hauj lwm ntawm lub axon thiab qhov ntev ntawm qhov pib ntu qhia txog qib ntawm plasticity uas tuaj yeem kho cov zis neuronal. Ib ntu pib ntev dua yog txuam nrog ntau dua excitability. Thawj ntu yog tshwj xeeb hauv kev ua cov hlab ntsha impulses vim muaj qhov siab ntawm voltage-gated sodium channels. Yog li ntawd, qhov peev xwm ua tau kuj pib los ntawm ntu pib.
Dab tsi yog qhov zoo sib xws ntawm Axon Hillock thiab ntu pib?
- Axon hillock thiab thawj ntu yog nyob rau ntawm neuron.
- Ob leeg muaj qhov hluav taws xob-gated sodium channels.
- Lawv ua kev xav.
- Ob lub qauv muaj xws li cytoplasm.
- Ob qho tib si axon hillock thiab ntu pib ua lub luag haujlwm tseem ceeb hauv kev tswj cov teeb liab impulses.
Qhov txawv ntawm Axon Hillock thiab ntu pib yog dab tsi?
Axon hillock muaj nyob hauv lub cev ntawm lub cev ntawm cov neuron, thaum thawj ntu yog nyob rau ntawm qhov sib thooj ntawm axon ntawm cov neuron. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm axon hillock thiab thawj ntu. Axon hillock tswj tag nrho inhibitory thiab excitatory signals, tab sis thawj ntu tswj cov teeb liab conductivity. Yog li, qhov no yog qhov sib txawv ntawm axon hillock thiab thawj ntu. Ntxiv mus, lub axon hillock muaj Nissl granules, thaum thawj ntu muaj cov high-density ion channels.
Cov hauv qab no infographic nthuav tawm qhov sib txawv ntawm axon hillock thiab thawj ntu hauv daim ntawv teev npe rau kev sib piv ntawm ib sab.
Summary – Axon Hillock vs Initial Segment
Axon hillock thiab ntu ntu yog ob feem ntawm cov neuron uas ua haujlwm ntawm kev coj ua impulses. Axon hillock yog tam sim no nyob rau hauv lub cell lub cev ntawm lub neuron, thiab thawj ntu yog tam sim no nyob rau hauv lub proximal ib feem ntawm lub axon ntawm lub neuron. Axon hillock tswj tag nrho inhibitory thiab excitatory signals, thaum thawj ntu tswj cov teeb liab conductivity. Tsis tas li ntawd, axon hillock muaj Nissl granules thaum thawj ntu muaj cov high-density ion channels. Yog li, qhov no qhia txog qhov sib txawv ntawm axon hillock thiab thawj ntu.
