Cardiac Cycle & Cardiac Pressure-Lecture 19 Exam 4 Flashcards
Major Components of the Cardiovascular System
-Heart
-Veins
-Capillaries
-Arteries
-Blood Vessels
Organization of the Cardiovascular System
-Pulmonary (lungs) Circulation
-Systemic (body) Circulation
-Coronary (heart) Circulation
Functions of the Cardiovascular System
-Transport materials entering the body (nutrients, O2, water)
-Transport materials within the body (hormones, immune cells, nutrients)
-Transport materials out of the body (metabolic wastes, CO2)
Cardiac Cycle
-The period between the start of one
heartbeat and the beginning of the next
-Systole & Diastole
Systole
-Contraction
-Chamber contracts
Diastole
-Relaxation
-Chamber fills with blood
Isovolumic
Unchanging volume, cardiac muscle contracts, but blood remains in the chamber
Ejection
Blood exits the chamber
Phases of the Cardiac Cycle
- Late Diastole
- Atrial Systole
- Isovolumic Ventricular Contraction
- Ventricular Ejection
- Isovolumic Ventricular Relaxation
Late Diastole
Both sets of chambers (atria & ventricles) are relaxed & filling with blood
Atrial Systole
Atrial contraction forces additional blood into ventricles
Isovolumic Ventricular Contraction
The ventricles contract, pressure rises, AV valves close but not enough pressure to open semilunar valves, blood has not left the ventricles
Ventricular Ejection
Ventricular pressure exceeds pressure in the aorta/pulmonary trunk, semilunar valves open and blood is ejected out of the left ventricle into the aorta
Isovolumic Ventricular Relaxation
Ventricles relax; pressure in ventricles falls, blood flows back into cusps of semilunar valves and they close
Atrial Systole Relation to Ventricular Filling
When the atria contract, the last bit of blood is forced into the ventricles to reach end diastolic volume of 130ml
Similarities Between Isovolumic Ventricular Contraction & Ventricular Ejection
-Ventricular Contraction
-Generate Pressure
-Part of the Systolic Phase
Relate the opening & closing of specific heart valves in each cardiac cycle phase to pressure changes in the heart chambers & the great vessels (aorta & pulmonary trunk)
- AV valves open; atrial pressure is greater than ventricular pressure
- AV valves close; atrial pressure is less than ventricular pressure
- SL valves open; Pulmonary valve pressure is greater than the P aorta and P. pulmonary trunk
- SL valves close; Pulmonary valve pressure is less than P aorta and P. Pulmonary trunk
Explain the pressure changes during the cardiac cycle in the atria & ventricles and their
relationship to blood flow through the heart & great vessels (aorta & pulmonary trunk)
Blood moving from areas of higher pressure to lower pressure
Cardiac Output (CO) & Units
-The amount of blood the heart pumps through the circulatory system in one minute
-L/min
Cardiac Output Equation
Cardiac Output = Heart Rate x Stroke Volume
