Cardiac cycle physiology ppt
- 2. Topic: Cardiac cycle Supervisor; Dr Kelaash Kumar Presantator ; Dr Abdul Qadeer
- 3. • DEFINATION • EVENTS • DURATION & DIVISION • SUB-DIVISION • HEART SOUNDS
- 4. Definition • Cardiac cycle is the period from beginning of one heart beat to begnning of other heart beat in which atrial and ventricle change pressure and changes in volume occurs in different phases. • OR • Mechanical and electrical events that causes cardiac contraction or ejection (ventricular systole ) , and relaxtion or filling (ventricular diastole) and pressure gradient develop between chambers which leads to ejection of stroke volume and farward flow of blood through body
- 5. EVENTS • Atrial and ventrical diastole(relaxation) • Filling phase • Atrial and venticle systole (contraction) • Ejection phase • Pump blood
- 6. Duration • > Normally heart beats rate 72bpm and • > cardiac cycle duration is 0.8 sec • Cardiac cycle inversely proportional to heart rate. • >Duration of • Diastole 2/3rd • Systole 1/3rd
- 7. Division cardiac cycle phase 1-Atrial systole • atrial systole is also known as last rapid filling or pre- systole • It is usually consider as last phase of ventricle diastole • Duration is 0.11sec • During this period only 10% of blood is forced from atria into ventricle • Intra atrial pressure increase • Contraction of atria musculature cause production 4th heart sound
- 8. Atrial diastole Atrial diastole start after atrial systole sumitaniously ventricular systole also start. Atrial diastole last for about 0.7sec The long atrial diastole is necessory because ,this is period during which atrial filling take place
- 9. Ventricle Events • CONTRACTION(SYSTOLE) • ISOVOLUMETRIC CONTRACTION PERIOD • EJECTION PERIOD • PROTO-DIASTOLE • RELAXTION (DIASTOLE) • ISOVOLUMETRIC RELAXTION PERIOD • RAPID FILLING • SLOW FILLING • LAST RAPID FILLING
- 10. ISOVOLUMETRIC CONTRACTION • First phase of ventricle systole • It last for 0.05sec • This is a type of muscle contraction characterized by increase in tension without any change n length of muscle fiber • Immediately after atrial contracion ,the atrioventriculoVavle are closed due to increase n ventricular pressure • Semilunar valve already closed • Now ventricle contract as closed cavities • In such way no change in the ventricle chamber or the length of fiber • Only the tension increase in ventricle musculture • Closure of AV-valve begnining of this phase produce 1st Heart sound
- 11. Ejection period • Due to opening of the semilunar valves and isotonic contraction ventricles blood is ejected out of both ventricle • Duration of ejection period =0.22sec • FIRST STAGE (RAPID EJECTION) • SECOND STAGE ( SLOW EJECTION)
- 12. 1ST STAGE RAPID EJECTION • Start immeditely after the opening of semilunar valves • During this stage large amount of blood is rapidly ejected from both ventricle • It last for 0.13sec
- 13. 2nd stage Slow ejection • During this stage the blood is ejected slowly with much less force • Duration of this period is 0.09sec
- 14. Proto diastolic • first sage of ventricle diastole hence the name protodiastole • Duration of this phase is 0.04sec • Due to the ejection of blood ,the pressure is aorta and pulmonary artry increased and pressure in ventricle drops • When intraventricle pressure become less than the pressure in aorta &pulmonary artery ,semilunar valve closed • Cosure of semilunar valve during this phase produce 2nd heart sound
- 15. ISOVOLUMETRIC RELAXTION PERIOD • It is stage of muscular relaxtion characterized by decrease in tension without any change in length of muscle fiber • During this period once again all the valve of the heart are closed • Intraventricle pressure decreases • Duration is 0.08sec
- 16. RAPID FILLING PHASE • When AV valves are opened there is sudden rush of blood from atria into ventricle • So this period is called first rapid filingperiod • Ventricles are also relaxed isotonically about 70% of filling take place during this phase which last for 0.11sec. • Rushing of blood into ventricle during this phase cause production of 3rd heart sound
- 17. Slow filling phase • After sudden rush of blood , ventricle filling become slow, now it is called slow filling • It is also called as diastsis • About 20% of filling occur in this phase • Durration last for 0.19 sec
- 18. LAST-RAPID FILLING • Last rapid filling phase occur because of atrial systole • After slow filling period the atria contract and push a small ammount of blood into ventricle • About 10%ventricle filling take place during this period • Flow of additional amount of blood into ventricles due to the atrial systole is atrial kick