The Cardiac Cycle Chapters 3 4 8
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A heart catheter can be placed in what three locations?
- 1.) ascending aorta
- 2.) left ventricle
- 3.) left atrium
What percent of the body is skeletal muscle?
What percent of the body is smooth muscle and cardiac muscle?
What are the two things that make cardiac muscles special from other types of muscles in the body?
- 1.) intercalated disks
- 2.) Syncytium
What is the purpose of intercalated discs? (5)
- 1.)They join the different myocytes together to form the functional syncytium.
- 2.) Are anchored into the myofibrils.
- 3.) They are dense structures that separate each fiber from its neighbor.
- 4.) They have low electrical resistance so they can conduct impulses rapidly.
- 5.) They allow for a tight connections so ions (action potential) can pass freely from one cell to another.
What is the purpose of the syncytium? (3)
- 1.) They allow all the myocytes to contract together as one unit.
- 2.) They are a group of cellls that are interconnected. It resembles a lattice work where the fibers divide and then recombine and then spread again.
- 3.) They allow the electrical stimulus to spread quickly and easily through the lattice work.
What are the approximate measurements of the cardiac muscle cell?
(Diameter and length)
- Diameter 25 u
- Length 100 u
What is the "a" wave?
Atrial contraction produces a small transient increase in left and right atrial pressure.
What causes the first heart sound?
Closure of the AV valves. The closure of the valves creates oscillation of the blood, which causes vibrations that can be heard with a stethoscope overlying the heart.
In what phase does systole end and diastole begins?
Valve closure is associated as a characteristic notch in the aortic and pulmonary artery pressure tracings.
How much blood remains in a ventricle after ejection is called what?
What is this amount?
- Called: End-systolic volume (ESV)
- 50 mL
How much blood the ventricles have after they are filled is called what?
What is the amount of blood in each ventricle after they are fillled?
- Called: End-diastolic volume
- Left ventricle-- 120 mL- at 8mmHg of pressure
- Right ventricle-- 4 mmHg og pressure
What is the "v" wave?
the peak of the atrial pressure just before the valve opens.
What is the "Y" wave?
Follows the V wave and is when the blood leaves the atria.
When is the S3 heart sound abnormal or normal?
It is abnormal for adults and may represent tensing of chordae tendinae and the AV ring.
It is normal in children.
When talking about the volume in the heart should always assume talking about what chamber?
the Left ventricle
What chamber is considered the "Power Horse"?
IN what phases are the atria filling?
All phases. The atria are continuously filling.
What heart sound sounds like "Lubb"?
Heart sound 1
What heart sound sounds like "Dubb"?
Heart sound 2
What is the word that means heart sound?
Is the venous side low or high pressure?
Is the arterial side low or high pressure?
the Cardiac cycle can also be called what?
the Wiggers diagram
A catheter placed inside the heart can be used for what?
To obtain pressure and volume information.
Systole refers to
events associated with ventricular contraction and ejection.
Diastole refers to
ventricular relaxation and filling
the P wave represents what on the EKG
depolarization of the atria
How much blood percent does atria contraction account for?
What does the QRS complex represent on the EKG?
What is ejection fraction (EF)?
- EDV - ESV = EF
- the typical value is 55%
What is preload?
it is the initial stretching of the cardiac myocytes prior to contraction, therefore, it is related to the sarcomere length at the end of diastole.
What is afterload?
is the load against which the heart must contract to eject blood.
What does hydrolyzes mean?
the protein is broken down into its components amino acids.
What does the Troponin Regulatory
What is TN-I responsible for?
inhibits myosin from attaching to actin.
What is TN-C responsible for?
binding site for calcium during excitation
What is TN-T responsible for?
Attachs to the tropomyosin.
What does the length of the sarcomere determine?
the force of the contraction
What is another name for the "Sliding Filament Theory"?
Walk Along Theory
Contraction lasts longer in skeletal muscle than in cardiac muscle. True or False
the force of the contraction also depends on
the concentration of calcium ions.
What is the velocity of the action potential in both atrial and ventricular muscle fibers?
0.3 to 0.5 meters per second
What is the velocity of the action potential in the Purkinje fibers?
what is the term that mean "the changes in contraction"
What is the term that means "the rate of myocyte relaxation"?
How many myofibrils are they in a muscle fiber?
hundreds to thousands
What is Fick's First Law?
Indicates the rate of diffusion.
Diffusion works well for...
Gases- oxygen and carbon dioxide.
electrolytes and fluids
What is one type of diffusion?
Transcapillary Fluid Exchange
What are the two basic fluid departments of the body?
1.) Intravascular compartments
2.) Extravascular compartments
What does the Intravascular compartments contain?
blood from within the cardiac chamber and blood vessels of the body.
What does the extravascular compartment contain?
- many sub compartments
- 1.) Cellular
- 2.) Interstitial
- 3.) Lymphatic
What is it called when fluid is push out of the capillaries?
What helps the fluid/blood to be pushed through the arteries?
What is Oncotic pressure?
Promotes reabsorption. It draws the fluid into the capillaries.
What is needed before Oncotic pressure can happen?
the protein Albumin, which is a plasma protein that generates about 70% of the oncotic pressure.
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