循环系统生理2(英文版)课件

Acute rheumatic fever Mitral stenosis -- Accentuated first sound Mitral stenosis – Presystolic murmur Mitral regurgitation -- systolic murmur Aortic insufficiency -- Loud systolic ejection murmur, third sound
Mechanical Events of the Cardiac Cycle
Click here to play the Mechanical Events of the Cardiac Cycle
Flash Animation
Summary of events in the left atrium, left ventricle, and aorta during the cardiac cycle
Cardiovascular Physiology
（心血管生理学）
Excitation-Contraction Coupling In Cardiac Muscle
The mechanism that couples excitation – an action potential in the plasma membrane of the muscle cell – and contraction of heart muscle
calcium ions released into the cytosol bind to troponin.
The calcium-troponin complex “pulls” tropomyosin off the myosin-binding site of actin, thus allowing the binding of the cross-bridge, followed by its flexing to slide the actin filament.
RIS--right intercostal space LIS—left intercostal space ICS--intercostal space LLSB--left lower sternal border
（心音图）
Heart valve defects causing turbulent blood flow and murmurs
Excitation-contraction coupling in cardiac muscle
Click here to play the Cardiac EC Coupling
Flash Animation
Cardiac cycle（心动周期）
• The cardiac events that occur from beginning of one heartbeat to the beginning of the next are called the cardiac cycle
Excitation-contraction coupling in skeletal muscle
Calcium ions regulate the contraction of cardiac muscle:
the entry of extracellular calcium ions causes the release of calcium from the sarcoplasmic reticulum (calcium-induced calcium release [钙诱导的钙释放]), the source of about 95% of the calcium in the cytosol.
What happens in the heart during each cardiac cycle?
• Pressure • Volume • Valves • Blood flow
Systole: ventricles contracting
Diastole: ventricles relaxed
Pressure changes in the right heart during a contraction cycle.
Role of atria and ventricles during each cardiac cycle
• Atria──primer pump • Ventricles──major source of power
Chest surface areas for auscultation of normal heart sounds
Four traditional value areas – Aortic space: 2RIS – Pulmonic valve: 2LIS – Tricuspid valve: 4ICS LLSB – Mitral valve: Apex
Passage of an action potential along the transverse tubule opens nearby voltage-gated calcium channels, the “ryanodine receptor,” located on the sarcoplasmic reticulum, and
Heart Sounds
• 1st sound – soft low-pitched lub – associated with closure of the AV valves – Marks the onset of systole
• 2nd sound – louder dup – associated with closure of the PA and aortic valves – Occurs at the onset of diastole