Plot blood pressure against time for one cardiac cycle in...

Name: Problem 8, Chapter 42: Campbell Biology
Uploaded: 2021-02-20T20:33:17-08:00
Duration: 5 min 5 s
Channel: Eric Goldman
Description: Plot blood pressure against time for one cardiac cycle in humans, drawing separate lines for the pressure in the aorta, the left ventricle, and the right ventricle. Below the time axis, add a vertical arrow pointing to the time when you expect a peak in atrial blood pressure.

Plot blood pressure against time for one cardiac cycle in humans, drawing separate lines for the pressure in the aorta, the left ventricle, and the right ventricle. Below the time axis, add a vertical arrow pointing to the time when you expect a peak in atrial blood pressure.

Key Concepts

Atrial Contraction

Atrial contraction is the phase where the atria actively contract to complete the filling of the ventricles. This event produces a peak in the atrial pressure waveform that can be highlighted on a time-pressure graph, and it occurs just before the onset of ventricular systole, providing a final boost to ventricular filling.

Aortic Pressure Dynamics

Aortic pressure dynamics describe the pressure changes in the aorta as it responds to the left ventricle's ejection of blood. The aortic pressure curve typically shows a rapid rise during ventricular systole followed by a gradual decline during diastole, reflecting both the force of the cardiac output and the elastic properties of the arterial walls.

Pressure Waveforms

Pressure waveforms are graphical representations that depict how blood pressure in various components of the cardiovascular system changes over time during the cardiac cycle. These waveforms help in understanding the dynamic processes of blood ejection from the ventricles and subsequent arterial pressure maintenance.

Cardiac Cycle

The cardiac cycle is the complete sequence of mechanical and electrical events that occur during one heartbeat. It includes phases such as atrial contraction, ventricular contraction (systole), and ventricular relaxation (diastole), each of which is reflected in the pressure changes recorded in the heart chambers and the great arteries.

Ventricular Pressure Dynamics

The pressure dynamics of the ventricles refer to the characteristic patterns observed in the left and right ventricular pressures during the different phases of the cardiac cycle. The left ventricle, responsible for systemic circulation, shows high peak pressures during systole, while the right ventricle, which supplies the lungs, exhibits lower pressures. Their pressure curves illustrate critical events like isovolumetric contraction, rapid ejection, and relaxation.

Transcript

00:01 So to understand pressure, we have to understand how the heart beats and which parts of the heart contract first.

00:07 So when we're starting with an electrical signal, we're going to start with the sa node and pass over an electrical signal to the av node.

00:19 As the electrical signal passes, the muscle cells making up the atria are going to contract and press in.

00:27 The electrical signal will travel down the bundle of hiss and propagate through the perkinji fiber.

00:36 And these will cause the ventricles to then contract.

00:45 So the atria will contract first, and then shortly after, the ventricles will contract.

00:57 So to understand the blood pressure, our general blood pressure runs from 120 millimeters mercury to 80 millimeters mercury, in the average male.

01:09 So over time, we have basically a general wave as our ventricles and atria contract, and push out blood into arterial system.

01:21 So on the top we have systole and on the bottom we have diastole.

01:33 Cistoli is the moment at which the ventricles are contracted and they're squeezing all the blood into the arterial system.

01:41 Diastole is the moment where none of the contractions are happening and the heart is filling with blood.

01:47 So let me erase what we have here.

01:50 This is just a general idea of how blood pressure works and i'll start with the pressure of the atrium, or not the atrium, the aorta.

02:01 Because the aorta is pretty symbolic of the overall pressure of the arterial system.

02:09 So we'll start at diastole...

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