Intliziyo

**Intliziyo **luhlobo lwesihlunu senyama olufumaneka kuso sonke isilwanyana esinethambo lomqolo. Sisihlunu esilingana nenqindi nesomelele kakhulu. Impompa igazi kuwo wonkw umzimba. Isoloko isenza intshukumo zokufinyela okanye xa intliziyo   ikhama igazi  ilikhamela kwamanye amalungu omzimba.   

Amagama athi *cardiac* kunye ne-*cardio* omabini athetha nge"ntliziyo", ngoko ke ukuba into inesimaphambili esingu-*cardio* or *cardiac*, loo nto inento yokwenza nentliziyo.  

I-myocardium ligama elithetha ngesihlunu sentliziyo: u-'myo' uvela kwigama lesiGrike elimele igama elithi 'isihlunu' - u-'mys', i-cardium ligama lesiGrike elimele intliziyo - 'ikardia'.

## Indlela emile ngayo
Intliziyo yomntu inamagumbi okanye iindawo ezivalekileyo. ezinye izilwanyana zinamagumbi amabini namathathu kuphela.  

Ebantwini, laa magumbi mane azii-*atria* ezimbini nee-*ventricles ezimbini*. I-Atria ithetha ngamagumbi amabini; ibe yona i-atrium  s talking about two chambers; atrithetha ngegumbi elinye.  kukho i-atrium yangasekunene ne-ventricle yangasekunene. La ke ngamagumbi afumana igazi elivela entliziyweni.  Ngawo la ampompa igazi elimpompela emiphungeni. Lisakufika emiphungeni igazi ligqitha nge-oksijini lize lishiye i-carbon dioxide. Eli gazi livela emiphungeni naloo lisiya kungena kwi-atrium nakwi-ventricle zangasekhohlo. Zona ke ezi atrium ne-ventricle zilikhuphela ngaphandle eli gazi lohlukane nomzimba. I-ventricle yangasekhohlo isebenza ngamandla ngokuphindwe  kathandathu kune-ventricle yangasekunene kuba ithwala igazi eline-oksijini.

Igazi lithwalwa ngemibhobho ehamba igazi. Le mibhobho ke ngoonothumela noonobuyisa. Igazi eliya entliziyweni lihamba ngoonobuyisa.  Igazi elishiya intliziyo lihamba ngoonobuyisa.  Oyena nothumela mkhulu ophuma kwintliziyo nge-ventricle yangasekunene ngunothumela oyi-*pulmonary*. (I-Pulmonary ithetha ngokumalunga nemiphunga.) Oyena nothumela mkhulu ophuma nge-ventricle yangasekhohlo yi-*aorta*.

Oonobuyisa ohamba ne-atrium yangasekunene zii-*superior vena cava* kunye ne-*inferior vena cava*. Yomibini le mithambo izisa igazi elivela emzimbeni lisiya ngasekunene lentliziyo. Oonobuyisa abahamba nge-atrium yasengasekhohlo zibizwa ngokuba ngoonobuyisa abazii-pulmonary. Aba nobuyisa beza negazi elivela kwimiphunga eliya ngasekunene kwentliziyo.  

Xa igazi lihamba lisuka kwi-atria lisiya kwii-ventricles lihamba ngemingxunyana yentliziyo eyi-valve. Xa igazi liphuma kwii-ventricles lihamba ngezi-valves. Ii-valves ziqinisekisa okokuba igazi lihamba kuphela ngendlela enye xa lingena naxa liphuma.  

Zine ii-valves zentliziyo, zezi: 
* Igazi elisuka kwi-Atria lisiya kwii-valves ze-ventricle 
** *I-valve ye-Tricuspid* – igazi lisuka kwi-atrium yangasekunene lisiya kwi-ventricle yangasekunene.
** *I-valve ye-Mitral *– igazi lisuka kwi-atrium yangasekhohlo isiya kwi-ventricle yangasekhohlo
* igazi elisuka kwii-Ventricles lisiya kwii- arteries
** *I-valve eyi-Pulmonic valve* –igazi lisuka kwi-ventricle yangasekunene lisiya emiphungeni (lihamba nge-*pulmonic artery*)
** *I-Aortic valve* – igazi liyahamba liphume kwi-ventricle yangasekhohlo liye kungena emzimbeni (lihamba nge-*aorta*)
Intliziyo ineenwebu (singathi ziingubo zayo) ezintathu. Inwebu yokuqala ukogquma intliziyo yi-pericardium. Iyingxo eyomeleleyo eyogqume intliziyo.  Kulandele inwebu ebizwa ngokuba yi-myocardium. Esi sisihlunu sentliziyo. Inwebu yokugqibela nengaphathi yi-endocardium. Le ke yinwebu emunyu-munyu eyohlula igumbi lentliziyo.

## Ukuthunyelwa nokubuyiselwa kwegazi entliziyweni: Cardiac cycle

Ukubetha kwentliziyo kuxa izihlunu zentliziyo zirhwaqela okanye zifingana. Oko kuthetha okokuba intliziyo iyashwabana ize ke oku kwenze okokuba igumbi eli eliyintliziyo lifinyele lithande ukuba lincinane.  Ngelo xesha kukhameka igazi litsho liputyuzekele ngaphandle liphume entliziyweni liye kungena kwimithambo yegazi. Emva kokuba iye yashwabana ke okanye yabuyelana okanye yafingana intliziyo, izihlunu zayo ziyakuyekelela ke ngoku zitsho ziyeke ukufingana ziswabuluke.  Ziyakuthi ke ngokuya ziswabuluka ziye zisanda ngokwanda, lize ke negazi liye libuyela ngokubuyela entliziyweni lide ligcwale apha kuyo.  

Xa izihlunu zentliziyo zifingana (okanye singathi xa intliziyo izicutha ibencinane izicuthela ngaphakathi) ibizwa ngokuba y*isystole*. Xa ke ngoku esi sihlunu siziyekelela (singazizicuthi), kuthiwa ke ngoku le y*idiastole*. Lo msebenzi we-systole wenziwa zii-atria zombini ngokubambisana. Kodwa yona i-atria yenza i-systole *phambi kokuba zenze ii-*ventricles. Nangona i-*atrial systole* isiza kuqala kune-*ventricular systole*, ziyenza zone ngaxeshanye kunjalo nje zibambisene i-diastole. Le knqubo ke kuthiwa yi-*cardiac diastole*

Zilandelelana ngolu hlobo: i-atrial systole → i-ventricular systole → i-cardiac diastole. Xa konke oku kusenzeka ngaxesha nye, kubizwa ngokuba yi-*cardiac cycle*.

## Iiznto ezenza okokuba intliziyo ibethe ngendlela
I-Systole (xa intliziyo izicutha okanye izikhama) yenzeka kuba ii-cells zezihlunu zentliziyo ziya zincipha ngokuncipha.  xa zisiba ncinane siyatsho okokuba ziyafingana.  Umbane otyhutyha-tyhutyha entliziyweni wenza okokuba ii-cells zifingane. Umbane uqala kwi-*sino-atrial node* (xa eli gama lishunqulwe lithi-SA Node) I-SA Node liqela lee-cells kwi-atria yangasekunene. ezi cells ziqala i-*electrical impulse*. Le electrical impulse ibeka umyinge nexesha emazifinyele ngalo ii-cells ze-cardiac muscle. Le ntshukumo ibizwa ngokuba yi-'atrial systole'. Iyakuthi ke  yakuhamba i-electrical impulse nge-*atrio-ventricular node* (Xa eli gama lishunqulwe lithi- eyi-AV Node). I-AV Node yenza okokuba isantya sokubetha kwentliziyo sihle. Ukwehla kwaso ke kwenza okokuba ii-electrical impulses zithathe ixesha ukufika.  Yile nto ke le yenza okokuba i-ventricular systole yenzeke emva kwe-atrial systole, itsho yenze okokuba lonke igazi liyishiye i-atria phambi kokuba i-ventricle ifingane (*ishwabane*). 

Emva kokuba ukubetha kwentliziyo kuhambe nge-AV Node, kuyakuhamba kudlule nge-*conduction system* ye-ventricle.Igama elithi conduction lithetha ubushushu okanye ukuhamba kombane kuloo nto uhamba ngayo. Oku kwenza okokuba ukubetha kwentliziyo kuye kwii-ventricles. Indawo yokuqala ye-conduction system yi-*bundle ye-His*. Igama elithi *His* ligama likagwirha u-(Wilhelm His, Jr) ekunguye owayifumanayo. I-Bundle ithetha uthotho lweengcingo eziqumbene ndawonye zaliqela elinye ngokumelana kwazo. Iyakuthi ke i-bundle  (*iqela lothotho lweengcingo ezihamba zilandela ngokumelana.*) zihamba ngokutyhuthya-tyhutyha isihlunu se-ventricle, Yahlulwe yangamasebe ee-*bundle amabini, *isebe le-bundle yangasekhohlo kunye nesebe le-bundle yandasekunene. ziyakuhamba ngesebe le-bundle yangasekhohlo zisiya kwi-ventricle yangasekunene zize ke zihambe ngesebe lee-bundle yangasekunene lonzihambe ke ziye kufika kwi-ventricle yangasekunene, ukubetha kwentliziyo kuhamba kuye kungena kwizihlunu ze-ventricular nge-Purkinje Fibers. Yiyo ke lento yenza okokuba i-ventricle ifingane kuthso kwenzeke i-ventricular systole.

## References
Zilandelelana ngolu hlobo: I-Sino-Atrial Node → i-Atria (systole) → i-Atrio-Ventricular Node → i-Bundle of His → i-Bundle branches → i-Purkinje Fibers → i-Ventricles (systole)

## i-ECG
I-ECG ligama aelisisishunqulelo segama elithi-**E**lectro**C**ardio**G**ram. likwabhalwa ngolu hlobo EKG igama elithetha i-**E**lectro**K**ardio**G**ram ngeJamani. I-ECG ibonisa okokuba wenzani ntonina umbane osentliziyweni.  I-ECG yenzeka ngokubeka ii-electrodes esikhumbeni somntu. Ii-electrodes zibona i-electricity ihamba ngentliziyo. oku kubhalwe ephepheni ngomatshini. lo mbhalo usephepheni yi-ECG.

Oogqirha xa befunda ngeentliziyo zabantu bajonga i-ECG. I-ECG ibonisa iintsholongwane zentliziyo ezithile ezifana nokuhlaselwa yintliziyo okanye iingxaki ezingesingqi sokubetha kwentliziyo (indlela ohamba ngayo umbane xa uhamba ngee-conduction system zentliziyo).

I-ECG ibonisa i-atrial systole. oku ke kubizwa ngokuba yi-**P-wave**. Emva koko kwenzeka i-nentricular systole. Oku ke kubizwa ngokuba kuyi-**QRS** okanye i-QRS-complex. Ikuthiwa yi-complex kuba kukho amaza aziintlobo ezintathu ngokwahlukana kwazo. Iliza eliyi- Q-wave, i-R-wave, kunye ne-S-wave. emva koko i-ECG ibonisa i-ventricular diastole. Le ke ibizwa ngokuba yi-**T-wave**. I-Atrial diastole yenzeka ngoko nayo. kodwa ayibonakali yahlukene kwi-ventricular diastole.

I-**PR-Interval** isisithuba phakathi kwe-atrial systole (P) ne-ventricular systole (QRS). I- **QT-Interval** isuka apho iqala khona i-QRS iye kuma apho i-T iphela khona. I-**ST-segment** isisithuba esiphakathi kwe-QRS ne-T.

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