BiologyHiranyagarbha · Class 11-12
Cardiac cycle: systole, diastole aur ek dhadkan ki kahani
Ek 'dhak-dhak' mein dil asal mein kitne steps karta hai?
Socho pehle… phir dekho jawab
Ek poori dhadkan (cardiac cycle) mein dil ke chambers baari-baari sikudte (systole) aur failte (diastole) hain, aur valves khulte-band hote hain — yehi 'dhak-dhak' ki aawaz banata hai.
Mechanism: pehle upar ke chambers (atria) sikudte hain aur khoon neeche ke chambers (ventricles) mein bhejte hain. Phir ventricles sikudte hain aur khoon dil se bahar dhakelte hain. Beech mein dil relax karta hai (diastole), jab chambers khoon se bharte hain.
Valves khulte-band hote hain taaki khoon sirf ek disha mein bahe; unka band hona hi 'lub-dub' dhadkan ki aawaz banata hai.
Nuance: heart rate ko dil ka apna 'pacemaker' (ek chhota electrical hissa) control karta hai, jo bina bahar ke signal ke bhi apne aap dhadakta hai. Exercise, stress aur nervous system iski speed badal sakte hain.
Ghar pe try karo
Stopwatch se apni resting heart rate naapo (15 second gino × 4). Phir 1 minute jumping jacks karke dobara naapo. Farak note karo aur socho: dil ne apni speed kyun badli hogi?
Wow!
Dil ka apna electrical system hota hai jo bina dimaag ke seedhe order ke bhi dil ko dhadkata rehta hai.
3 sawaal
- Systole kya hai?
Jawab dekho
Dil ka sikudna. Systole matlab dil ke chambers ka sikudna, jisse khoon aage badhta hai.
- 'Lub-dub' aawaz kaha se aati hai?
Jawab dekho
Valves ke khulne-band hone se. Valves ka band hona hi dhadkan ki aawaz banata hai.
- Heart rate ko basic taur par kaun control karta hai?
Jawab dekho
Dil ka apna electrical hissa (pacemaker). Dil ka apna electrical system (pacemaker) apni pacing khud set karta hai.
NCERT se jodo: NCERT Class 11 Biology — body fluids and circulation