Summary PHYSIO 1 Lab Exam III Study Guide

Lab Exam III Study Guide
Cardiac Function

Be able to follow a drop of blood through the pulmonary and systemic circuits. Know which structures contain
oxygenated and deoxygenated blood.

 Right atrium (De-oxygenated blood)
 Tricuspid valve (De-oxygenated blood)
 Right ventricle (De-oxygenated blood)
 Semilunar Pulmonary Valve (De-oxygenated blood)
 Pulmonary Artery (De-oxygenated blood)
 Pulmonary Arterial (De-oxygenated blood)
 Pulmonary Capillary Bed (De-oxygenated blood)
 Pulmonary Venule (Oxygenated blood)
 Pulmonary Vein (Oxygenated blood)
 Lef Atrium (Oxygenated blood)
 Mitral / Bicuspid Valve (Oxygenated blood)
 Lef Ventricle (Oxygenated blood)
 Semilunar Aortic Valve (Oxygenated blood)
 Aorta (Oxygenated blood)

Explain why the electrical activity of the heart can be transmitted to the skin.

 Since body fluids contain a high concentration of electrolytes, the electrical activity generated by the
heart travels throughout the body and can easily be monitored by electrodes placed on different areas
of the skin.

Be able to identify the waves on a normal EKG recording and be able to describe the electrical events
associated with each wave.

 P Wave
o Starting at the SA node, depolarization of pacemaker cells occurs. The single spreads across bo
atria, causing the cells to depolarize and contract, inducing Atrial Systole. Pressure slightly
increases in ventricles.
 The QRS Complex
o The depolarizing signal reaches the AV node and enters the bundle of his and then to the
Purkinje fibers along the ventricle walls. The contractile fibers, located along the ventricle walls,
rapidly contract, inducing Ventricular Systole. Atrial repolarization also occurs during this wave.
“R” on the EKG is the “Lub” sound of the heart. Pressure greatly increases to 120mmHg in the
ventricles.
 T Wave
o Ventricular repolarization. “Dub” sound occurs, pressure decreases in ventricles and Diastole
begins.

, o


Be able to correspond the lub and dub sounds of the heart and pressure changes of the ventricles with an EK

 The QRS Complex
o “R” on the EKG is the “Lub” sound of the heart. Pressure greatly increases to 120mmHg in the
ventricles.
 T Wave
o Ventricular repolarization. “Dub” sound occurs, pressure decreases in ventricles and Diastole
begins.


What accounts for the normal lub and dub sounds of the heart during auscultation?

 “Lub” sound is caused by the closing of the AV valves after the atria have pumped blood into the
ventricles
 “Dub” sound is caused by the closing of the aortic and pulmonary valves right after the ventricles have
ejected the blood


Define a heart murmur. What are the two main causes for this condition?

o Heart murmur
 Is when the heart valves do not close or open properly, causing blood to flow backwards
or improperly during systole.
o Causes:
 Flow murmurs
 Are caused by high blood flow and higher blood pressure, seen during heavy
exercise and increased BP.
 Valve murmurs