The Cardiac Cycle Flashcards
What is blood pressure?
The control of blood flow through the heart
What does end diastolic volume entail?
When the ventricles are in the last phase of their diastole and they have maximum volume of blood
Does ventricular systole begin the sane time as atrial diastole?
Yes
What is the isovolumetric contraction phase?
It is when blood volume does not change but pressure rises and ventricular pressure is higher than atrial pressure and Sv opens and eject blood to arteries
What is Stroke Volume?
When the volume of blood pumped out by one ventricle with each beat
What is the end systolic volume?
Blood still remaining in the chambers
What is the dictionary notch?
Where the backflow rebounds off the closed cusps
What is the diffrence between the right and left side of the heart?
At the right side Pulmonary circulation is a low pressure circulation has a much thinner myocardium
What is a heart murmur?
When blood strikes obstructions ans flow is turbulent and there’s an abnormal heart sound
What is a stenosic valve?
A valve that fails to open immediately and it restricts blood flow through valve
What is cardiac output?
The amount of blood pumped by each ventricle in a minute
What formula is used to calculate CO?
Heart Rate × Stroke Volume
What are the factors that affect CO?
Heart Rate
Stroke Volume
What is the Brainbridge reflex?
It’s an atrial reflex
Adjusting heart rate in response to Venus return
What is the purpose of stretch receptors in right Atrium?
They trigger increase in heart rate through increased sympathetic activity
What is contractility?
The ability for a cardiac muscle fiber to contract at any given fiber length
What does the Sterling Law state?
That when there is more blood in the ventricle at the beginning of contraction the greater the Stroke Volume
What us the EDV dependent on?
The amount of blood that enters venous circulation
What is the length tension relationship?
It’s the force created by a myocardial muscle is directly related to the length of the sarcomere
If the length of the sarcomere increases tension during contraction increases and if the tension increases the stroke volume will also increase and if there is more blood flowing in the ventricles the muscle fibers will stretch and contract and eject more blood
What does Starlings law say?
The more blood there is in the ventricles at the beginning of contraction the greater the stroke volume
What is venous return?
The amount of blood that enters the heart from venous circulation
What is pre load?
Load placed on the Cardiac muscle before contraction
What is contractility of the heart controlled by?
Nervous and endocrine system
What are the factors that affect cardiac output?
Heart Rate
Strike volume
Changing the EDV or the ESV
Adjusted by ANS or hormones
What are the factors that affect heart rate?
Cardiac plexus (parasympathetic and sympathetic nerve network)
Cardiac centers
What is the parasympathetic innervation?
The vagus nerve carrying preganglionic fibers to small ganglia in cardiac plexus
What is the sympathetic innervation of the Cardiac plexus?
Postganglionic neurons located in the cervical and upper thoracic ganglia
What are the Cardiac centers of the medulla oblongata?
Cardioaccelatory center which controls sympathetic neurons which increase heart rate
Cardioinhibitory center which controls the parasympathetic neurons which slows heart rate
What is the effect of the sympathetic stimulation on stroke volume?
NE is released by postganglionic fibers of the Cardiac nerves
Epinephrine and NE is released by the suprarenal and causes ventricles to contract with more force and increases ejection fraction and decrease the ESV
What is the effect of the sympathetic stimulation on stroke volume?
NE is released by postganglionic fibers of the Cardiac nerves
Epinephrine and NE is released by the suprarenal and causes ventricles to contract with more force and increases ejection fraction and decrease the ESV
What is the parasympathetic activities effects on stroke volume?
Ach is released by the vagus nerve and reduces force if cardiac contractions
