The Cardiac Cycle Chapters 3 4 8

• 1.) ascending aorta
• 2.) left ventricle 
• 3.) left atrium

40%

10%

• 1.) intercalated disks
• 2.) Syncytium

• 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.

• 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.

• Diameter 25 u
• Length 100 u

Atrial contraction produces a small transient increase in left and right atrial pressure.

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.

Phase 5

Valve closure is associated as a characteristic notch in the aortic and pulmonary artery pressure tracings.

• Called: End-systolic volume (ESV)
• 50 mL

• Called: End-diastolic volume
• Left ventricle-- 120 mL- at 8mmHg of pressure
• Right ventricle-- 4 mmHg og pressure

the peak of the atrial pressure just before the valve opens.

Follows the V wave and is when the blood leaves the atria.

It is abnormal for adults and may represent tensing of chordae tendinae and the AV ring.

It is normal in children.

the Left ventricle

Left ventricle

All phases. The atria are continuously filling.

Heart sound 1

Heart sound 2

Photocardiogram

low pressure

high pressure

the Wiggers diagram

To obtain pressure and volume information.

events associated with ventricular contraction and ejection.

ventricular relaxation and filling

depolarization of the atria

20-30%

ventricular depolarization

• EDV - ESV = EF
• the typical value is 55%

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.

is the load against which the heart must contract to eject blood.

the protein is broken down into its components amino acids.

• TN-I
• TN-C
• TN-T

inhibits myosin from attaching to actin.

binding site for calcium during excitation

Attachs to the tropomyosin.

the force of the contraction

Walk Along Theory

false.

the concentration of calcium ions.

0.3 to 0.5 meters per second

4 m/s

Inotropy

Lusitropy

hundreds to thousands

Indicates the rate of diffusion.

Gases- oxygen and carbon dioxide.

and 

electrolytes and fluids

Transcapillary Fluid Exchange

1.) Intravascular compartments

2.) Extravascular compartments

blood from within the cardiac chamber and blood vessels of the body.

• many sub compartments
• 1.) Cellular
• 2.) Interstitial
• 3.) Lymphatic

"fluid filtration"

"hydrostatic pressure"

Promotes reabsorption. It draws the fluid into the capillaries.

the protein Albumin, which is a plasma protein that generates about 70% of the oncotic pressure.