Chapter 19 - Section 19.5 - Study Guide - Assess Your Learning Outcomes - Page 740: 5

**1. Atrial Systole (Atrial Contraction):** - **Chambers:** Both atria contract. - **Valves:** AV valves (tricuspid and mitral valves) are open. Semilunar valves (pulmonary and aortic valves) are closed. - **ECG:** P wave represents atrial depolarization. - **Heart Sounds:** No significant heart sounds. - **Blood Movement:** Blood is pushed into the ventricles. - **Blood Ejection:** Blood is not ejected during this phase. - **Volume/Pressure Changes:** Atrial volume decreases, pressure increases slightly. **2. Ventricular Systole (Ventricular Contraction):** - **Chambers:** Both ventricles contract. - **Valves:** AV valves are closed. Semilunar valves are open. - **ECG:** QRS complex represents ventricular depolarization. - **Heart Sounds:** S1 (lub) sound occurs due to the closure of AV valves. - **Blood Movement:** Blood is ejected from the ventricles into the pulmonary artery and aorta. - **Blood Ejection:** Blood is ejected from the ventricles. - **Volume/Pressure Changes:** Ventricular volume decreases, pressure increases significantly. **3. Isovolumetric Relaxation:** - **Chambers:** Both ventricles relax. - **Valves:** All valves are closed. - **ECG:** No specific wave corresponds to this phase. - **Heart Sounds:** No significant heart sounds. - **Blood Movement:** Blood doesn't move significantly, but the ventricles begin to relax. - **Blood Ejection:** Blood is not ejected during this phase. - **Volume/Pressure Changes:** Ventricular volume remains constant, pressure decreases. **4. Ventricular Diastole (Ventricular Relaxation):** - **Chambers:** Both atria and ventricles relax. - **Valves:** AV valves are open. Semilunar valves are closed. - **ECG:** T wave represents ventricular repolarization. - **Heart Sounds:** No significant heart sounds. - **Blood Movement:** Blood flows from the veins into the atria, then from the atria into the ventricles. - **Blood Ejection:** Blood is not ejected during this phase. - **Volume/Pressure Changes:** Atrial volume increases, ventricular volume increases, pressure remains low. Throughout these phases, the coordinated opening and closing of valves, along with depolarization and repolarization events, ensure the efficient movement of blood through the heart. Changes in blood volume and pressure contribute to the proper filling and ejection of blood, while the characteristic heart sounds (S1 and S2) are a result of valve closures. Blood is pumped out of the ventricles into the pulmonary artery and aorta during systole, and blood returns to the atria and flows into the ventricles during diastole. Blood pressure and volume changes in the left atrium, left ventricle, and aorta are critical for maintaining proper blood circulation and delivering oxygen and nutrients to the body's tissues.

**1. Atrial Systole (Atrial Contraction):** - **Chambers:** Both atria contract. - **Valves:** AV valves (tricuspid and mitral valves) are open. Semilunar valves (pulmonary and aortic valves) are closed. - **ECG:** P wave represents atrial depolarization. - **Heart Sounds:** No significant heart sounds. - **Blood Movement:** Blood is pushed into the ventricles. - **Blood Ejection:** Blood is not ejected during this phase. - **Volume/Pressure Changes:** Atrial volume decreases, pressure increases slightly. **2. Ventricular Systole (Ventricular Contraction):** - **Chambers:** Both ventricles contract. - **Valves:** AV valves are closed. Semilunar valves are open. - **ECG:** QRS complex represents ventricular depolarization. - **Heart Sounds:** S1 (lub) sound occurs due to the closure of AV valves. - **Blood Movement:** Blood is ejected from the ventricles into the pulmonary artery and aorta. - **Blood Ejection:** Blood is ejected from the ventricles. - **Volume/Pressure Changes:** Ventricular volume decreases, pressure increases significantly. **3. Isovolumetric Relaxation:** - **Chambers:** Both ventricles relax. - **Valves:** All valves are closed. - **ECG:** No specific wave corresponds to this phase. - **Heart Sounds:** No significant heart sounds. - **Blood Movement:** Blood doesn't move significantly, but the ventricles begin to relax. - **Blood Ejection:** Blood is not ejected during this phase. - **Volume/Pressure Changes:** Ventricular volume remains constant, pressure decreases. **4. Ventricular Diastole (Ventricular Relaxation):** - **Chambers:** Both atria and ventricles relax. - **Valves:** AV valves are open. Semilunar valves are closed. - **ECG:** T wave represents ventricular repolarization. - **Heart Sounds:** No significant heart sounds. - **Blood Movement:** Blood flows from the veins into the atria, then from the atria into the ventricles. - **Blood Ejection:** Blood is not ejected during this phase. - **Volume/Pressure Changes:** Atrial volume increases, ventricular volume increases, pressure remains low. Throughout these phases, the coordinated opening and closing of valves, along with depolarization and repolarization events, ensure the efficient movement of blood through the heart. Changes in blood volume and pressure contribute to the proper filling and ejection of blood, while the characteristic heart sounds (S1 and S2) are a result of valve closures. Blood is pumped out of the ventricles into the pulmonary artery and aorta during systole, and blood returns to the atria and flows into the ventricles during diastole. Blood pressure and volume changes in the left atrium, left ventricle, and aorta are critical for maintaining proper blood circulation and delivering oxygen and nutrients to the body's tissues.