Inqubo Yokushukuma Kwemizwa
Ukudluliselwa kwemizwa yemizwa kuyinto ebalulekile ohlelweni lwemizwa, okuvumela ukuxhumana phakathi kwama-neurons naphakathi kwama-neurons nezinye izitho zomzimba. Ukuqonda ukuthi imizwa yemizwa ihamba kanjani kunganikeza ukuqonda okujulile ngendlela ubuchopho bomuntu nomzimba osebenza ngayo. Lesi sihloko sizochaza kabanzi izindlela ezisekela le nqubo, kusukela encazelweni eyisisekelo kuya endleleni imizwa yemizwa engathinta ngayo imisebenzi yomzimba.
Isingeniso kuma-Neuron
Ama-neuron ayizinyunithi eziyisisekelo zesimiso sezinzwa, ezibhekwa njengamaseli akhethekile kakhulu anekhono lokuthumela nokwamukela izimpawu zikagesi. Isakhiwo se-neuron sakhiwe izingxenye ezintathu eziyinhloko: umzimba weseli (i-soma), ama-dendrite, nama-axon. Ama-dendrite ayizinhlungu ezimfushane ezithola izimpawu bese ziwadlulisela emzimbeni weseli, kuyilapho ama-axon kuyizinhlungu ezinde ezithwala izimpawu zisuka emzimbeni weseli ziye kwamanye ama-neurons noma amaseli e-effector.
Amandla e-membrane
Ukuze uqonde inqubo yemizwa, kubalulekile ukuqonda umqondo wekhono le-membrane. Ama-neurons ane-membrane engangeni, evumela i-gradients ethile yokuhlushwa kwama-ion. Esimweni sokuphumula, ingaphakathi le-neuron lineshaja engemihle uma kuqhathaniswa nengaphandle. Lesi simo sibizwa ngokuthi ikhono lokuphumula, elisukela cishe ku--70 mV.
Amandla Esenzo
Inqubo eyinhloko ekudlulisweni kwemizwa yokuphazamiseka yikhono lokusebenza, ushintsho olusheshayo kumandla olwelwesi oluhamba nge-axon ye-neuron. Amandla okusebenza aqala lapho i-neuron ithola isikhuthazo esinamandla ngokwanele, okubangela ushintsho lokuqala ekungeneni kwe-membrane kuma-ion e-sodium (Na+).
1. Ukususwa kwe-polarization – Isikhuthazo sivula iziteshi ze-Na+ ion, okuvumela i-Na+ ukuthi igeleze ingene esitokisini. Lokhu kubangela ukuthi ishaja ye-membrane ishintshe isuke ku-negative iye ku-positive.
2. Ukuphinda kuvele i-polarization – Ngemva kokuqeda ukwenzeka kwe-polarization ephezulu, iziteshi ze-Na+ ziqala ukuvala kuyilapho iziteshi ze-potassium (K+) zivuleka, okuvumela i-K+ ukuthi iphume esitokisini. Le nqubo ibuyisela i-membrane charge esimweni esingesihle.
3. I-Hyperpolarization – Uma i-K+ ishiya kakhulu, ulwelwesi lwe-neuron luba lubi kakhulu kune-rest potential, ngaphambi kokuba luphinde luzinze.
Ukuqhuba Umfutho
Amandla esenzo avame ukuqala egqumeni le-axon bese ehamba nge-axon eya esigungwini se-axon. Kunezinhlobo ezimbili eziqashelwayo zokuqhuba: ukuqhuba okuqhubekayo kanye nokuqhuba usawoti:
– Ukuqhuba okuqhubekayo kwenzeka kuma-axon angenamyelin lapho amandla esenzo kumele akhiqizwe ngokulandelana eceleni kwe-axon.
– Ukuqhutshwa kwe-saltatory kwenzeka kuma-axon e-myelinated lapho ama-impulse 'egxuma' esuka kwelinye i-node le-Ranvier aye kwelinye, okusheshisa ukudluliselwa kwama-impulse.
Ukudluliselwa kwe-Synaptic
Uma amandla esenzo efika esigungwini se-axon, isignali kagesi iguqulwa ibe isignali yamakhemikhali ehamba nge-synaptic cleft iye ku-neuron elandelayo. Le nqubo ihilela:
1. Ukukhishwa kwama-neurotransmitter: Amandla esenzo abangela ama-vesicles aqukethe ama-neurotransmitter ukuthi ahambe aye ku-membrane ye-presynaptic futhi akhiphe okuqukethwe kwawo ku-synaptic cleft.
2. Ukusabalala kwe-neurotransmitter kudlule isikhala futhi kubopha kuma-receptors ku-membrane ye-postsynaptic.
3. Ukuqaliswa Kwe-Post-synaptic Potential: Kuye ngohlobo lwe-neurotransmitter kanye ne-receptor, lokhu kungakhiqiza i-excitatory postsynaptic potential (EPSP) noma i-inhibitory postsynaptic potential (IPSP), okuthonya ukuthi i-neuron elandelayo izokhiqiza yini i-action potential.
Izici Ezithinta Inqubo Yokushukuma Kwezinzwa
Inqubo yokuphazamiseka kwemizwa ithonywa yizici ezahlukahlukene:
– Ububanzi be-Axon: Ama-Axon anobubanzi obukhulu azoqhuba ama-impulse ngokushesha kune-axon encane.
– Izinga lokushisa: Ukwanda kwezinga lokushisa kungandisa isivinini sokuqhutshwa kwe-impulse.
– Ukuba khona kwe-Myelin: Njengoba kushiwo, i-myelination yandisa isivinini sokuqhutshwa kwe-impulse.
– Ibhalansi ye-Electrolyte: Ama-ion anjenge-Na+, K+, ne-Ca2+ abalulekile ekulinganiseni amandla e-membrane kanye namandla esenzo.
Ukusetshenziswa Kokuqonda Izinzwa Ezishukumisayo
Ukuqonda imizwa yezinzwa kunezindlela eziningi zokusebenzisa emikhakheni eyahlukene, okuhlanganisa:
– Imithi: Ukuxilongwa nokwelashwa kwezifo zezinzwa ezifana nesifo sokuwa, i-multiple sclerosis, kanye ne-neuropathy.
– I-Pharmacology: Ukuthuthukiswa kwemithi elawula umsebenzi we-neurotransmitter, esetshenziswa ekwelapheni izimo ezinjengokucindezeleka kanye ne-schizophrenia.
– Ubuchwepheshe be-Neuro: Ukuthuthukiswa kwamadivayisi okufakelwa angahlanganiswa nesistimu yezinzwa ukusiza iziguli ezilahlekelwe ukusebenza kwezinzwa noma kwemisipha.
Isiphetho
Inqubo yokushukuma kwemizwa iwukuxhumana okuyinkimbinkimbi kwezinqubo ze-bioelectric kanye ne-biochemical, okuvumela ukuxhumana okuphumelelayo ngaphakathi kwesimiso sezinzwa. Kusukela ekususweni kwe-polarization kuya ekudlulisweni kwe-synaptic, isinyathelo ngasinye sidlala indima ebalulekile ekuqinisekiseni impendulo esheshayo nefanele yomzimba ezintweni ezishukumisayo. Intuthuko yakamuva ocwaningweni nasebuchwephesheni iyaqhubeka nokujulisa ukuqonda kwethu ukuthi le nqubo ayigcini nje ngokusekela impilo kodwa futhi iqhubela phambili ukusungula izinto ezintsha emikhakheni ehlukahlukene yesayensi neyezokwelapha. Ukuqonda nokusebenzisa le nqubo kuvula amathuba amaningi okuthuthukiswa kwezindlela zokwelapha kanye nobuchwepheshe besikhathi esizayo obungathuthukisa kakhulu ikhwalithi yokuphila komuntu.
