Video narration
Ek mutthi jitna dil bina ruke poore sharir mein khoon kaise chalata rehta hai? Haath ke pump jaisa, dil dabaav se khoon ko judi nalion mein aage bhejta hai. Magar yah ek nahin, do jude hue pump hain: daayan phephdon ke liye, aur baayan sharir ke liye. Har taraf do kaksh hote hain. Upar ka atrium khoon leta hai, aur neeche ka ventricle use baahar dhakelta hai. Sharir se lautta khoon pehle daayen atrium, phir daayen ventricle mein jaata hai. Vahan se vah phephdon tak pahunchta hai. Phephde usmein oxygen jodte hain aur carbon dioxide nikaalte hain. Ab yah taaza khoon baayen atrium, phir baayen ventricle mein aata hai. Baayan ventricle ise poore sharir mein bhejta hai. valves chhote darwaazon ki tarah khoon ko peeche lautne se rokte hain. Har dhadkan electrical signals se shuru hone wala kramabaddh sankuchan hai. Yahi chakr lagataar dohraata rehta hai. To jawaab hai: dil do taalmel wale pumps se kaam karta hai - daayan khoon ko phephdon tak bhejta hai, baayan oxygen-yukt khoon sharir tak, aur valves pravaah ko ek disha mein rakhte hain.