CAM201 Lecture Notes - Lecture 4: Systolic Geometry, Valvular Heart Disease, Heart Valve

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jademoose588

8 Jun 2018

School

University of Tasmania

Department

CAM

Course

CAM201

Professor

Dino

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Basics of the Cardiac Cycle

• Contraction and relaxation cause cyclic alterations in the pressures within the heart chambers.

• Pressure differences between heart chambers lead to the flow of blood between chambers

and also the major blood vessels in contact with the heart.

• The flow of blood through the heart is unidirectional because of the presence and properties

of the heart valves.

• There are 5 basic steps to a cardiac cycle

1. Diastole - Relaxation and Filling

Muscle:

• Atria relaxed

• Ventricles relaxed

Pressure:

• Ventricular pressure is less than atrial

pressure

• Ventricular pressure is much less than

pulmonary artery and aortic pressure

Valves

• AV valves open

• Semilunar valves closed

Blood flow:

• Blood flows passively into both atria and

ventricles down the pressure gradient

• High flow rate because of low resistance

2. Atrial Systole/Ventricular Diastole

Muscle:

• Atria contract

• Ventricles relaxed

Pressure:

• Ventricular pressure is less than atrial

pressure

• Ventricular pressure is much less than

pulmonary artery and aortic pressure

Valves

• AV valves open

• Semilunar valves closed

Blood flow:

• Active blood flow into ventricles as atria

contract

3. Ventricular Systole - Isovolumic Contraction

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Muscle:

• Atria relax

• Ventricles contracting

Pressure:

• Ventricular pressure is greater than atrial

pressure

• Ventricular pressure is rising but still lower

than pulmonary artery and aortic pressure

Valves

• AV valves snap shut

• Semilunar valves closed

Blood flow:

• Ventricular volume does not change, ie. No

blood flow (isovolumic)

4. Ventricular Systole - Ejection

Muscle:

• Atria relax

• Ventricles contracting

Pressure:

• Ventricular pressure is greater than atrial

pressure

• Ventricular pressure is greater than

pulmonary artery and aortic pressure

Valves

• AV valves snap shut

• Semilunar valves open

Blood flow:

• Blood ejected into pulmonary artery and

aorta from both left and right ventricles

• The volume of blood ejected = stroke

volume

• Atria begin to fill passively with blood

5. Ventricular Diastole

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Muscle:

• Atria relax

• Ventricles relaxing

Pressure:

• Ventricular pressure is greater than atrial

pressure

• Ventricular pressure has fallen below

pulmonary artery and aortic pressure

Valves

• AV valves closed

• Semilunar valves closed

Blood flow:

• Ventricular volume does not change, ie. No

blood flow (isovolumic)

Then the cycle restarts

Wiggers Diagram

• The diagram illustrates the coordinated variation in each factor/values as the heart beats

• The Wiggers diagram contains:

o Details of pressure changes in the LEFT side of the heart

o Details of volume changes in the LEFT side of the heart

o An ECG

o Phonocardiogram (heart sounds)

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Document Summary

Blood flow: blood flows passively into both atria and ventricles down the pressure gradient, high flow rate because of low resistance, atrial systole/ventricular diastole. Pressure: ventricular pressure is less than atrial pressure, ventricular pressure is much less than pulmonary artery and aortic pressure. Blood flow: active blood flow into ventricles as atria contract, ventricular systole - isovolumic contraction. Pressure: ventricular pressure is greater than atrial pressure, ventricular pressure is rising but still lower than pulmonary artery and aortic pressure. Blood flow: ventricular volume does not change, ie. no blood flow (isovolumic, ventricular systole - ejection. Pressure: ventricular pressure is greater than atrial pressure, ventricular pressure is greater than pulmonary artery and aortic pressure. Blood flow: blood ejected into pulmonary artery and aorta from both left and right ventricles, the volume of blood ejected = stroke volume, atria begin to fill passively with blood, ventricular diastole.

Related Questions

Match the following terms describing the physical/mecahnical events with the correct phases of the cardiac cycle. Each phase may be used more than once.

- A. B. C. D.	All 4 cardiac valves are closed and all 4 chambers are relaxed during this phase.
- A. B. C. D.	The maximum amount of blood is in the ventricles at the end of this phase.
- A. B. C. D.	The pressure in the ventricles is higher than in the atria, but lower than in the arteries, during this phase.
- A. B. C. D.	The semilunar valves are open and the AV valves are closed during this phase.
- A. B. C. D.	The atria contract at the end of this phase.
- A. B. C. D.	The pressure in the ventricles is higher than the pressure in both the atria and the arteries during this phase.
- A. B. C. D.	Systole begins with this phase.

A.	isovolumetric relaxation
B.	ventricular ejection
C.	isovolumetric contraction
D.	ventricular filling

1. What is the significance of the ST segment?

a. ventricular depolarization

b. ventricular systole

c. atrial systole

d. atrial depolarization

2. Ventricular contraction is also known as ventricular __________.

3. Ventricular diastole is also known as ventricular __________.

A nurse takes your blood pressure and tells you the numbers are 110/70. What are your blood pressures?

rev: 11_20_2014_QC_55932

a. Systolic = 110 mmHg, Diastolic = 70 mmHg

b. Diastolic = 110 mmHg, Systolic = 70 mmHg

The brachial artery is the most common site of blood pressure measurement with the sphygmomanometer.

True

False

Cardiac cycle is the ____________________________.

a. The volume of blood ejected by each ventricle in one minute

b. One complete contraction and relaxation of all chambers of the heart

c. The pressure blood exerts on the wall of blood vessels

d. Depolarization and repolarization of the ventricles

coffeesalmon954

1) Check all that are components of the sympathetic innervation of the heart.

Check All That Apply

Cervical sympathetic ganglion

Spinal cord Spinal cord

Vagus nerve (CN X)

Cardiac nerve

Sympathetic postganglionic axon

2) Check all that occur during ventricular contraction.

Check All That Apply

The AV valves open to allow blood to enter the ventricles from the atria.

The semilunar valves remain closed to prevent backflow of blood into the ventricles.

The semilunar valves open to allow blood to flow into the large arteries.

The AV valves close to prevent backflow of blood into the atria.

3) Put the pattern of circulation into the correct order, beginning with the pulmonary circulation.

Blood enters the plumonary arteries and travels to the lungs.

Blood leaves the right side of the heart.

Blood enters the plmonary veins.

Blood enters the system arteries.

Blood delivers oxygen to the tissues, and then enters systematic veins.

Blood enters the left side of the heart.

4)Check all that are characteristics of cardiac muscle.

Check All That Apply

Cells are long and cylindrical.

Cells are short and branching.

Cells have multiple nuclei at the periphery of the cell.

Cells have one or two nuclei in the center of the cell.

They are composed of thick and thin filaments.

The functional contractile unit is the sarcomere.

CAM201 Lecture Notes - Lecture 4: Systolic Geometry, Valvular Heart Disease, Heart Valve

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