Alterations in the Function of the Heart

Arterial vessels carry blood, venous vessels carry blood.

oxygenated; deoxygenated

The only venous vessles that carry oxygenated blood are the _ and __.

pulmonary venules and veins

Trace blood flow "forward" through the heart.

SVC / IVC → RA → RV → PA → lungs → PV \n → LA → LV → aorta → systemic circulation

Trace blood flow "backward" through the heart.

LV --> LA --> PV --> lungs (edema) \n lungs -->PA -->RV --> RA --> SVC/IVC --> (edema)

Define systole

part of the heart beat where the RV and LV are contracting and ejecting blood from their chambers

what is the sinoatrial (SA) node?

structure located in the right atrium that tells the heart to "beat" or squeeze by sending out an electrical signal

what is stroke volume?

amount of blood ejected per contraction (or squeeze, or with each beat of the heart)

• The average amount is around 70ml/beat.

what is an ECG?

electrical signal that is created by the heart, starting with the SA node, can be recorded on paper by using specialized patches on the skin and recoding equipment.

• Each depolarization, contraction, and repolarization of the chambers of the heart can be recorded on paper and analyzed by nurses and other healthcare providers

Define Cardiac Output (C.O.)

amount of blood ejected by the LV p/min

• Normal CO is 4 - 6 liters of blood per minute

Normal Sinus Rhythm

• normal heart rhythm - pattern that the electrical impulses travel through the heart

what is the calculation for cardiac output?

C.O. = stroke volume( heart rate )

What three conditions influence or impact stroke volume?

1. contractility
2. preload: venous return to the heart
3. afterload: arterial resistance to forward flow of blood out of the heart