Cardiac Cycle (FINAL) Flashcards
What is happening to the heart when the P-Wave is being recorded?
P-Wave
- Depolarization of atria in response to SA node triggering
What is happening to the heart when the PR-Wave is being recorded?
PR Interval
- Delay of AV node to allow filling of ventricles
What is happening to the heart when the QRS-Wave is being recorded?
QRS Complex
- Depolarization of ventricles, triggers main pumping contractions
What is happening to the heart when the T-Wave is being recorded?
T-Wave
- Ventricular repolarization
What is happening to the heart when the ST-Wave is being recorded?
ST Segment
- Beginning of ventricle repolarization
- Should be flat
Aortic valve opens
A-V valve closes
Systole
Diastole
Systole
Ventricular Volume
Ventricular Pressure
Atrial Pressure
Aortic Pressure
A-V valve opens
Aortic valve closes
Atrial systole
Diastasis
Rapid inflow
Isovolumic relaxation
Aortic valve opens
Ejection
Isovolumic contraction
Superior vena cava
Sinoatrial (SA) node
“Pacemaker”
Internodal pathway
Atrioventricular (AV) node
Atrioventricular (AV) bundle
(Bundle of His)
Bundle branches
Purkinje fibers
Right atrium
Left atrium
Purkinje fibers
Interventricular septum
SA Node
Atrial muscle
AV node
Ventricular muscle
Ventricular muscle
Ventricular muscle
Purkinje fibers
Bundle branches
Common bundle
AV node
Atrial muscle
Sinus node
What is the purpose of the cardiac cycle?
Purpose of the Cardiac Cycle
- To fill the ventricles with blood
What is meant by “ventricular filling”
Ventricular Filling
- Blood enters/flows into the ventricles by gravity
- Fills up the bottom chambers through the open tricuspid and bicuspid (mitral) values
What is meant by systole of the atria?
Systole of Atria
- Atria (left & right) contract and squeeze
What is the purpose of atrial systole
Purpose of atrial systole
- Pushes more blood into the ventricles
What is meant by the “LOAD” phase of the cardiac cycle?
LOAD
- Blood enters the ventricles via gravity from the open tricuspid and bicuspid valves
- Left and right atria contract (atrial systole)
What is meant by systemic circulation?
Systemic Circulation= body circulation
- Both sides (left and right) are pumping together at the same time
- The valves are alternating
- Pulmonary and aortic valves open and close together
- Tricuspid and bicuspid valves open and close together
What type of blood does pulmonary veins have?
Pulmonary veins have oxygenated blood unlike systemic/body veins
What type of blood does the pulmonary artery carry?
Pulmonary artery carries deoxygenated blood unlike the systemic/body arteries
What is happening when the ventricles are contracting?
Ventricles contract (right and left)
- Both the left and right ventricles squeeze
- Systole
- Causes the tricuspid and bicuspid valves to close
- “Lub” = isovolmetric contraction
When are the tricuspid and bicuspid valves closing?
Tricuspid and bicuspid valves close during ventricular contraction
*Both ventricles are forcing the valves to close
What is meant by “LUB”?
Lub = isovolumetic contraction
- Both the right and left ventricles are forcing the tricuspide and bicuspid valves to close
When the tricuspid and bicuspid valves contract what is happening to the semilunar valves
Semilunar valves open when tricuspid and bicuspid valves close
Where does the blood flow once the semilunar valves are open?
Semilunar valves (pulmonary and aortic valves) open
- Blood enters the pulmonary and aortic arteries
- Pulmonary artery blood goes to lungs
- Aortic artery blood goes to the body’s organs
What is happening during the SHOOT/Ejecting phase of the cardiac cycle?
Shoot/ Ejecting Phase
- Left and right ventricles contract (systole)
- Tricuspid and bicuspid valves close
- LUB
- Pulmonary & aortic valves are forced open
- Blood enters pulmonary and aortic arteries
- Pulmonary artery blood goes to lungs
- Aortic artery blood goes to body’s organs
What is meant by diastole?
Diastole
- Relaxation and expandation of left and right ventricles
What is happening to the semilunar valves during diastole
- Semilunar valves (pulmonary and aortic) close to keep blood out
- DUB
Differentiate between lub and dub
- Lub
- Closing of the tricuspid and bicuspid valves due to ventricular contraction
- Systole
- Closing of the tricuspid and bicuspid valves due to ventricular contraction
- Dub
- Closing of the pulmonary and aortic valves due to ventricular relaxation
- Diastole
- Closing of the pulmonary and aortic valves due to ventricular relaxation
What is the SCORE phase of the cardiac cycle?
Score Phase
- The right and left ventricles expand and relax
- Diastole
- Pulmonary and aortic valves close
- Dub
- Tricuspid and bicuspid vavles open
Atrial pressure increase when the atria does what?
Atrial pressure increase when the atria contracts/squeezes
Ventricle Pressure
The ventricle’s graph is larger than the atria due to what two factors?
Ventricular Pressure
- Ventricles have more force
- Ventricles are going against gravity
What is the order the the pressurization of the atria and venticles?
The atria pressurizes first then the venticles
What is happening during aortic pressure?
Aortic Pressure
- The ventricles are squeezing before the valves are open
- Pressure
- When the valves are open, this means the pressure is released
- The arteries get the full pressure of the blood
Explain ventricular volume
Ventricular Volume
- The size of the ventricles
Explain the relationship of ventricular volume in terms of systole and diastole.
Ventricular Volume = Inverse relationship
- Systole = contraction of ventricles
- Ventricular volume goes down
- Diastole = relaxation of ventricles
- Ventricular volume goes up
What is the relationship between the aorta and ventricle?
When the aorta contracts the ventricle expands
What is Starling’s Law of the Heart?
Starling’s Law of the Heart
- “If you strech the heart muscle, the heart contracts harder.”
- Rubberband effect
- Pre-loading/atrial kick
If you stretch the heart with more blood what will happen?
Stretch the heart with more blood
- The ventricles stretches/atrial kicks
- Atrial kicks = the atria is squeezing to make the ventricles stretch more
- Kicks the heart with extra blood
What is atrial kick?
Atrial Kick
- The atria is squeezing/contracting to make the ventricles stretch more
The P Wave correlates to what?
P wave correlates to atrial depolarization
During the P wave that is the condition of the SA node?
P Wave = atrial depolarization
SA node is depolarized
What is the purpose of the SA node?
SA node = pacemaker
The QRS wave correlates to what node?
QRS wave correlates to AV node
The T wave correlates to phase during the cardiac cycle?
T wave correlates to diastole/relaxation
