Extrasystole and compensatory pause oftoad heart Teaching Center for Experimental Medicine
Extrasystole and compensatory pause of toad heart Teaching Center for Experimental Medicine
Extrasystole a premature cardiac contraction that is independent of the normal rhythm and arises in response to an impulse outside the sinoatrial node. AM八f 八AA /个 Compensatory pause The pause following an extrasystole,when the pause is long enough to compensate for the prematurity of the extrasystole; the short cycle ending with the extrasystole plus the pause following the extrasystole together equal two of the regular cycles
Extrasystole a premature cardiac contraction that is independent of the normal rhythm and arises in response to an impulse outside the sinoatrial node. Compensatory pause The pause following an extrasystole, when the pause is long enough to compensate for the prematurity of the extrasystole; the short cycle ending with the extrasystole plus the pause following the extrasystole together equal two of the regular cycles
ERP:Effective refractory period 20- RRP:Relative refractory period -20 mV -40 ERP 60 -80 -100」 100ms A:Action potential B:Mechanical contraction Significance: The cardiac muscle is refractory to any stimulus during the contraction phase and thus tetanus cannot be produced in cardiac muscle. 2. The cardiac muscle can relax and get filled up with blood and then contract to pump out the blood
ERP: Effective refractory period RRP: Relative refractory period Significance: 1. The cardiac muscle is refractory to any stimulus during the contraction phase and thus tetanus cannot be produced in cardiac muscle. 2. The cardiac muscle can relax and get filled up with blood and then contract to pump out the blood
Aim: 1.To investigate the changes of excitability in a cardiac cycle. 2. To understand the significance of long effective refractory period of heart
Aim : 1. To investigate the changes of excitability in a cardiac cycle. 2. To understand the significance of long effective refractory period of heart
Experimental manubrium sterni Procedure 1.Dissection Procedures Destroy the brain and spinal cord of a toad and fasten it to a board,ventral side up; Use scissors to make a longitudinal incision on chest wall to expose the heart
manubrium sterni 1.Dissection Procedures : • Destroy the brain and spinal cord of a toad and fasten it to a board, ventral side up; • Use scissors to make a longitudinal incision on chest wall to expose the heart ; Experimental Procedure
heart pericardium 2.Exposing the heart Hold the cardiac pericardium with forceps and carefully remove the membrane from the heart with scissors. The heart is then periodically moistened with Ringer's solution
pericardium heart 2.Exposing the heart Hold the cardiac pericardium with forceps and carefully remove the membrane from the heart with scissors. The heart is then periodically moistened with Ringer's solution
3.Connecting the ventricle to the transducer Clamp the apex of the ventricle with a clip during ventricle diastole.Be careful and don't hurt the ventricle. * Connect the clip to the transducer with a thin thread and adjust the tension of the ventricle. Stimulation electrode
3. Connecting the ventricle to the transducer Clamp the apex of the ventricle with a clip during ventricle diastole. Be careful and don’t hurt the ventricle. Connect the clip to the transducer with a thin thread and adjust the tension of the ventricle. Stimulation electrode
4.Choose protocol,Setup the stimulus parameters,observe and record the result. N性e■9 图929只m:是 Protocol:Circulation-Extrasystole and compensatory pause e
4. Choose protocol, Setup the stimulus parameters, observe and record the result. Protocol: Circulation - Extrasystole and compensatory pause
Simple Stimulate:Amplitude:5.0 Voltage,Wavelength:1.0ms Click button“Start Stimulate” ON9不5集 ·gg@是2 3.11 LAAA Inverted triangle:trigger an electrical stimulus at the intersection of the horizontal line and the descending section of the curve after click the button
Simple Stimulate：Amplitude：5.0 Voltage, Wavelength：1.0ms Click button“Start Stimulate” Inverted triangle: trigger an electrical stimulus at the intersection of the horizontal line and the descending section of the curve after click the button
七91G4云与新都 州实续线安装有确正工 国家 An extrasystole A compensatory pause3 18 10 的 electrical stimuli e D 3o?·N口4洲n
electrical stimuli An extrasystole A compensatory pause