Analyzing Heart Data
• H.5.2 Analyse data showing pressure and volume changes in the left atrium, left
ventricle and the aorta, during the cardiac cycle.
Useful Tutorial site
http://library.med.utah.edu/kw/pharm/hyper_heart1.html
1.
On the above graph what is happening at point A. In your answer be sure to describe the
following:
a. Identify if the Atrial/ ventricle are in systole or diastole
The atria are filling with blood and they are about to undergo, ATRIAL Systole – atria
pumps/ contracts and pumps more blood into the ventricular
b. Describe the relative pressure ( high/low) of the atria and ventricles
Immediately following point A there is a slight increase in arterial pressure.
c. Describe the relative volume (high/low) of the atria and ventricles.
Immediately following point A , there is a slight decrease in the volume of the atria
b/c the atria is contracting.
d. If pressure and/or volume for any heart chamber or the aorta has changed from the
previous point of the graph explain why.
Immediately following point A, there is a slight decrease in the volume of the atria
because the atria is contracting, and a decrease in volume causes an increase of
pressure (Boyles Law) . The increase in pressure is also due to the atria filling with
blood.
e. Identify what is happening to the AV/ SL valves (open/closed).
AV valves are open, SL valves are closed.
f. Describe what is happening at the SN and AV nodes.
An impulse arising from the SA node results in depolarization and contraction of the atria
(the right atrium contracts slightly before the left atrium). The A wave on the EKG/ ECG is
due to this atrial depolarization
.
2.
On the above graph what is happening at point B. In your answer be sure to describe the
following:
a. Identify if the Atrial/ ventricle are in systole or diastole
The ventricles filling with blood and they are about to undergo ventricular systole
b. Describe the relative pressure ( high/low) of the atria and ventricles
Firs the ventricles are filling with blood which increase the pressure of the ventricles and
then as the ventricule contracts the pressure in the ventricle increases dramatically.
c. Describe the relative volume (high/low) of the atria and ventricles.
The volume of the ventricle is about to decrease because the ventricles are about to
contract.
d. If pressure and/or volume for any heart chamber or the aorta has changed from the
previous point of the graph explain why.
Pressure and volume of the ventricle is starting to change because the ventricle is first
filling with blood and then is about to start to contracting.
e. Identify what is happening to the AV/ SL valves (open/closed).
Immediately following point B on the graph, the ventricles fill with blood, and their
pressure in the ventricles exceed sthe pressure in the atrias; This causes the
atrioventricular (AV) valves close & hence the first heart sound is made LUB
f. Describe what is happening at the SN and AV nodes.
The electrical impulse propagates from the AV node through the His bundle and Purkinje
system to allow the ventricles to contract from the apex of the heart towards the base
3.
On the above graph what is happening at point y. In your answer be sure to describe the
following:
a. Identify if the Atrial/ ventricle are in systole or diastole
ventricular systole
b. Describe the relative pressure ( high/low) of the atria and ventricles
While the ventricles continue contracting, the pressure in the ventricles (red) exceeds the
pressure in the aorta and pulmonary arteries (green); the semilunar valves open, blood
exits the ventricles, and the volume in the ventricles decreases rapidly (white). As more
blood enters the arteries, pressure there builds until the flow of blood reaches a peak.
c. Describe the relative volume (high/low) of the atria and ventricles.
SEE ABOVE
d. If pressure and/or volume for any heart chamber or the aorta has changed from the
previous point of the graph explain why.
SEE ABOVE
e. Identify what is happening to the AV/ SL valves (open/closed).
The semilunar (aortic and pulmonary) valves open during the part of ventricular systole.
AV VALVES are closed
f. Describe what is happening at the SN and AV nodes.
NOTHING IS HAPPPENING HERE/
On the above graph what is happening at point z In your answer be sure to describe the
following:
a. Identify if the Atrial/ ventricle are in systole or diastole
Beginning of Diastole for both chambers
b. Describe the relative pressure ( high/low) of the atria and ventricles
Throughout this and the previous two phases, the atrium in diastole has been filling
with blood on top of the closed AV valve,
The pressure in the ventricles continues to drop.
c. Describe the relative volume (high/low) of the atria and ventricles.
Ventricular volume is at a minimum and is ready to be filled again with blood
d. If pressure and/or volume for any heart chamber or the aorta has changed from the
previous point of the graph explain why.
Ventricles are in diastole and are no longer contracting.
e. Identify what is happening to the AV/ SL valves (open/closed).
4.
Immediately preceding point z when the pressure in the aorta exceeded the pressure in the
ventricle, the second heart sound ("dup") occurs when the semilunar valves close. At the
beginning of this phase the AV valves are closed.
f.
Describe what is happening at the SN and AV nodes.
NOTHing
Analyzing an EKG
1.
Describe what is happening at point P.
An impulse arising from the SA node results in depolarization and contraction of
the atria (the right atrium contracts slightly before the left atrium). The P wave is
due to this atrial depolarization.
2. Identify what QRS represents in the cardiac cycle.
The electrical impulse propagates from the AV node through the His bundle and Purkinje system
to allow the ventricles to contract from the apex of the heart towards the base.
The QRS complex is due to ventricular depolarization, and it marks the beginning of ventricular
systole. It is so large that it masks the underlying atrial repolarization signal.
3. Identify what is happening in the T wave.
The T wave is due to ventricular repolarization. The end of the T wave marks the end of
ventricular systole electrically.