Virtual Lab - Heart

CARDIOVASCULAR PHYSIOLOGY: ELECTROCARDIOGRAPHY LAB

Cardiac muscle cells

contract in response to a rapid series of electrical potential changes that travel through the heart along the conduction system

Sinoatrial Node (SA)

• Under normal conditions, electrical activity of the heart is spontaneously generated by S, the heart’s physiology peacemaker:

  • Electrical impulse propagated throughout the right and left atria - stimulates myocardium of the atria to contact

  • Then to the atrioventricular node (AV)

AV node function

• To critically delay in conduction system

• Prevents atria and ventricles from contracting at the same time

• Provides time for blood to flow from the atria to ventricles

AV Bundle

• The distal portion of the AV node (bundle of His)

• Splits into right and left bundle branches in the interventricular septum

Purkinje Fibers

• Both bundle branches taper out into subendocardiac conducting network

• It stimulates individual groups of ventricular myocardial cells to contract

Electrical current and contracting

• As electrical current passes through the heart, the cardiac muscle tissue is electrically excited, causing it to contract

• After contracting, muscle cells relax again until next electrical current passes through and the cycle is repeated

Electrocardiogram (ECG)

• An interpretation of the electrical activity (depolarization and repolarization) of the heart over a period of time

• Detected by electrodes attached to the outer surface of the skin and recorded by a device external to the body

Conduction System of the Heart

How are an interval and a segment different?

An interval measures at least one wave and one flat area, while a segment includes only a flat area of the tracing

BLOOD: BLOOD TYPING LAB

Blood Types

Determined by antigens that are present on the surface of red blood cells (RBCs, also known as erythrocytes

Red Blood Cell membranes

• Contain glycoproteins and glycolipids that determine your ABO blood type and proteins that determine your Rh (+/-) blood type

  • ABO blood type is determined by the presence of A, B, both AB, or neither (O)

  • Rh blood type is determined by the presence of (+) or lack of (-) the D antigen

Blood Plasma

• May contain antibodies depending on ABO and Rh blood types:

  • Type A: you will have anti-B antibodies

  • Type B: you will have anti-A antibodies

  • Type O: you will have anti-A and anti-B antibodies

  • Type AB: you will NOT have any anti-A nor anti-B antibodies

  • No one has anti-D (Rh) antibodies unless they are Rh- AND have been previously exposed to Rh+ blood

Donating Blood

• Blood can only be donated from a person w/ a specific ABO antigen to a person without antibodies for that antigen

  • Type A: cannot donate to Type B or Type O; both have anti-A antibodies

  • Type B: cannot donate to Type A or Type O; both have anti-B antibodies

  • Type O: can potentially donate to everyone; their blood has no antigen to attack. Type O should first have its own anti-A and anti-B antibodies removed

  • Type AB: cannot donate to Type A blood; they have anti-B antibodies, or people with Type B; they have anti-A antibodies

  • Rh+ blood should not be transfused to a person who is Rh- ; however, Rh- blood can be donated to a person who is Rh+.

All Blood Type’s Donor