Maitiro Ekugadzirisa pH yeMuviri
Muviri wemunhu unoshanda zvakanaka chete mukati memamiriro ezvinhu akasimba mukati. Chimwe chezvinhu zvakakosha zvinofanirwa kutariswa zvakanyanya ipH, iyo inoyera mwero weacidity kana basicity (alkalinity) yemushonga. Muvanhu, pH yeropa yakajairika iri pakati pe7,35–7,45. Nhamba iyi inoita seiri nyore, asi kunyangwe kutsauka kudiki kunogona kukanganisa mashandiro ema enzyme, metabolism yemasero, mashandiro etsinga, uye kusimba kwetsandanyama dzemwoyo. Nokudaro, muviri une nzira yekudzora pH ine layer yakawanda, inokurumidza, uye inotsigirana.
Kunzwisisa pH uye kukosha kwe acid-base balance
pH inotsanangurwa nehuwandu hwehydrogen ions (H⁺) mumvura yemuviri. Kana H⁺ yakakwira, ndipo panowedzera acidity; kana H⁺ yadzikira, ndipo panonyanya kuva nyore. Maitiro akasiyana-siyana emakemikari mumuviri anogadzira maacid nemabhesi sezvibereko. Semuenzaniso, metabolism yemacarbohydrate nemafuta inogadzira carbon dioxide (CO₂), iyo inogona kuumba carbonic acid, nepo metabolism yemapuroteni ichigadzira maacid asinganyungudike akadai sesulfuric acid nephosphoric acid.
Sei zvichikosha kuchengetedza pH yeropa? MaEnzymes—mapuroteni anokurumidzisa reaction yemakemikari—ane pH yakakwana. Kuchinja kwepH kunogona kushandura chimiro cheprotein, kukanganisa ma bond emakemikari, uye kushandura mashandiro ema receptors nema ion channels. Nekuda kweizvozvo, masisitimu akasiyana emuviri anogona kusangana nedambudziko. Acidosis (yakaderera kwazvo pH) inogona kukonzera kudzikira kwekugadzikana kwemoyo, arrhythmias, uye kudzikira kwemhinduro yetsinga ku catecholamines. Alkalosis (yakakwira zvakanyanya pH) inogona kukonzera zviratidzo zvakaita sekukwenya, kurwadziwa, uye kunyange kurova kwemoyo zvisina kurongeka nekuda kwekuchinja kwekusunga calcium kumapuroteni.
Manyuko emaacids nemabhesi mumuviri
Muviri unoburitsa "maacid" kubva kuzvinhu zviviri zvikuru. Chekutanga, maacid anoshanduka, ari muchimiro cheCO₂, anogadzirwa nekufema kwemasero. CO₂ inoburitswa nyore nyore nemapapu, saka izwi rekuti volatile. Chechipiri, maacid asingavhunduke (fixed acids) anobva muprotein uye phospholipid metabolism, zvakaita sesulfuric nephosphoric acids. Maacid asingavhunduke haagone kuburitswa nemapapu uye anotsamira paitsvo kuti abudiswe.
Kune rumwe rutivi, muviri unogadzirawo mabhesi, rimwe rawo riri bicarbonate (HCO₃⁻), iro rinoita basa rakakosha sechinochengetedza plasma. Kuenzana uku pakati pemaacids nemabhesi kunochengetedzwa nehurongwa hwe pH regulation.
Miti mitatu yekutonga pH: buffers, mapapu, uye itsvo
Maitiro ekudzora pH yemuviri anogona kunzwisiswa senzira nhatu huru dzekudzivirira:
1. Sisitimu yemakemikari inogadzirisa zvinhu (inokurumidza, inoshanda mumasekonzi)
2. Masisitimu ekufema (anokurumidza, maminetsi kusvika kumaawa)
3. Nhumbu (yakasimba asi inononoka, maawa akawanda kusvika kumazuva)
Izvi zvitatu zvinoshanda pamwe chete kuchengetedza pH yeropa yakagadzikana pasinei nekuchinja kwekugadzirwa kweacid-base.
1) Sisitimu yekudzivirira chemakemikari: nzira yekutanga yekudzivirira
Buffer iboka reasidhi-base risina simba rinoramba shanduko mu pH ne "kubata" kana "kuburitsa" H⁺ ions. Mabuffer haabvisi acid mumuviri, asi anogadzirisa pH kwenguva pfupi kuti mamwe masisitimu agone kugadzirisa.
Bicarbonate buffer (HCO₃⁻/H₂CO₃)
Chinhu chinonyanya kukosha muropa iBicarbonate system, iyo inosanganisira maitiro:
CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ + HCO₃⁻
Kana H⁺ yawedzera (kuwedzera kweacidity), HCO₃⁻ inosunga H⁺ kuti igadzire H₂CO₃, iyo inogona kushandurwa kuita CO₂ yoburitswa nemapapu. Kusiyana neizvi, kana H⁺ yadzikira (yakanyanya kuoma), H₂CO₃ inogona kuora kuti ibudise H⁺ kudzikisa pH zvakare.
Chinhu chakanaka chehurongwa uhwu ndechekuti zvikamu zvahwo zvinogona kudzorwa nenhengo mbiri: mapapu anodzora CO₂ uye itsvo dzinodzora HCO₃⁻.
Buffer hemoglobin uye mapuroteni eplasma
Hemoglobin iri mumasero matsvuku eropa chinhu chine simba nekuti inogona kusunga H⁺. Kana CO₂ ikapinda muma erythrocytes, imwe yacho inoshandurwa ne enzyme carbonic anhydrase kuita H⁺ neHCO₃⁻. H⁺ inobva yasungwa nehemoglobin, nokudaro isingawedzere acidity yeropa zvakanyanya. Mapuroteni eplasma anewo mapoka eacid-base anogona kuchengetedza shanduko dzepH, kunyange hazvo mupiro wawo uri mudiki pane wehemoglobin.
Phosphate buffer
Sisitimu yephosphate (H₂PO₄⁻/HPO₄²⁻) inonyanya kushandiswa mumasero nemumvura yeitsvo. Iyi nzira yekudzivirira inodiwa zvikuru pakuburitsa acid muitsvo, sezvo phosphate ichigona "kubata" H⁺ muweti.
2) Kudzora kwemapapu: kunodzora CO₂
Mapapu anodzora pH nekutonga kuti CO₂ yakawanda sei inoburitswa kuburikidza nekufema. Nekuti CO₂ ine chekuita zvakananga nekuumbwa kweH⁺ mukuita kwebicarbonate, shanduko mukufema dzichakanganisa pH yeropa.
– Kana ropa rikava neacidic (acidosis): muviri unowedzera mhepo inofema (hyperventilation) kuti CO₂ yakawanda ibudiswe. Kudzikira kweCO₂ kuchachinja reaction kuenda kuruboshwe, H⁺ ichidzikira uye pH ichiwedzera.
– Kana ropa rikava nealkaline yakawandisa (alkalosis): kufefetera kunogona kunonoka (hypoventilation) zvekuti CO₂ inochengetwa, reaction inochinja kuenda kurudyi, H⁺ inowedzera, pH inodzikira kusvika padanho renguva dzose.
Kudzora uku kunodzorwa nenzvimbo yekufema iri muuropi, iyo inogamuchira zviratidzo kubva kumakemoreceptors. Makemoreceptors epakati anonzwa shanduko muCO₂ (kuburikidza nekuchinja kwepH yemvura yemuuropi), nepo makemoreceptors emumativi (mumiviri ye carotid neaortic) anonzwa huwandu hwepH yeropa neokisijeni.
Zvisinei, kufema kune miganhu. Kufema kwakanyanya kunogona kukonzera kupera kweokisijeni (hypoxia). Nokudaro, kubhadharwa kwekufema kwealkalosis hakugone kuramba kuripo nekusingaperi.
3) Kudzora kweitsvo: kunodzora kuburitswa kwebicarbonate neacid
Itsvo ndidzo dzinodzora nguva refu acid-base balance. Kazhinji, itsvo dzinochengetedza pH nenzira nhatu huru:
1. Kutorwazve kwebicarbonate yakasefetwa (HCO₃⁻)
2. Kubviswa kwema H⁺ ions
3. Kugadzirwa kwebicarbonate itsva (HCO₃⁻ itsva) kuti itsive iyo yaishandiswa kudzima acid.
Kudzoserwa kweBicarbonate
HCO₃⁻ yakawanda iri muplasma inoseferwa pa glomerulus. Itsvo dzinofanira "kudzosa" HCO₃⁻ kudzivirira kuti isarasike muweti. Mu proximal tubule, masero etubular anoburitsa H⁺ mu tubular lumen. H⁺ iyi inosangana neHCO₃⁻ kuumba H₂CO₃, iyo inobva yaputswa kuita CO₂ naH₂O. CO₂ inodzokera mumasero etubular uye inoshandurwa kuita HCO₃⁻, iyo inozodzoserwa muropa. Iyi nzira inochengetedza bicarbonate reserves zvinobudirira.
Kubviswa kweasidhi setitrated acid uye ammonium
Itsvo dzinoburitsa H⁺ zvakanyanya mumhando mbiri:
– Titration acid (kunyanya phosphoric): H⁺ inosungwa neHPO₄²⁻ kuti igadzire H₂PO₄⁻ uye inoburitswa muweti.
– Ammonium (NH₄⁺): Itsvo dzinopwanya glutamine kuti igadzire NH₃ (ammonia), iyo inobva yabatana neH⁺ kuti igadzire NH₄⁺. Maitiro aya akakosha kana muviri ukasangana neacidosis isingaperi nekuti inogona kuwedzera zvakanyanya kugona kwekubvisa acid.
Chero H⁺ inobviswa seNH₄⁺ kana H₂PO₄⁻ inonyanya kusanganiswa nekuumbwa kweHCO₃⁻ itsva iyo inodzoserwa muropa, nokudaro ichibatsira kukwidza pH.
Pfungwa yemuripo: kana imwe system ikakanganiswa
Zvirwere zve acid-base zvinowanzo patsanurwa muzvikamu zvinotevera:
– Matambudziko ekufema: shanduko huru muCO₂ (semuenzaniso, hypoventilation → respiratory acidosis; hyperventilation → respiratory alkalosis).
– Matambudziko emetabolism: shanduko huru muHCO₃⁻ kana acid load (semuenzaniso manyoka akanyanya kurasikirwa nebicarbonate → metabolic acidosis; kurutsa kwenguva refu kurasikirwa negastric acid → metabolic alkalosis).
Muviri unozobhadhara kuburikidza nedzimwe nzira: kusashanda zvakanaka kwemuviri kunobhadharwa nemapapu (kuchinja kwemhepo), ukuwo kusashanda zvakanaka kwekufema kunobhadharwa neitsvo (kuchinja kudzoserwa kweHCO₃⁻ uye kubuda kweH⁺). Kubhadhara kunobatsira kuunza pH pedyo neyakajairika, asi kazhinji hakudzoreri zvizere kusvika chikonzero chacho chagadziriswa.
Penutup
Kudzora pH yemuviri muenzaniso mukuru wekururama kwehurongwa hwehomeostasis yemunhu. Makemikari anogadzirisa mukati memasekonzi mashoma kuti agadzirise shanduko dzepH, mapapu anokurumidza kugadzirisa CO₂ kuburikidza nekuchinja kwemhepo inofefetera, uye itsvo dzinodzora zvakasimba kubuda kweasidhi uye bicarbonate reserves kuti dzirambe dzakagadzikana kwenguva refu. Aya masystem matatu anopindirana, achichengetedza pH yeropa iri mukati mechikamu chidiki chinoita kuti masero ashande zvakanaka. Kunzwisisa masystem aya kwakakosha kwete chete kubiology uye mushonga, asiwo pakuziva kuti kunyangwe kukanganiswa kudiki mukufema, mashandiro eitsvo, kana metabolism kunogona kukanganisa hutano hwemuviri wese.
