The Cardiovascular System “A muscular pump equipped with one- way valves and a system of large and small plumbing tubes within which the blood travels.” = pump = pump = plumbing tubes = plumbing tubes

Early development of the heart and circulatory system 2 weeks post-conception-2 weeks post-conception- 3 weeks-3 weeks- 4 weeks-4 weeks- By week 8-By week 8-

During this period the fetal heart is at great risk from agents that may cause congenital defects. RUBELLA

FETAL CIRCULATION Before birth- Umbilical Vessels- 1. one 1. one 2. two 2. two

To bypass the liver Umbilical vein  ductus venosus  inferior vena cava  right atrium -> uumuum

To bypass the lungs Right Atrium  Foramen Ovale  Left Atrium  Left Ventricle  Aorta  Body (majority of blood) (majority of blood)Or Right Atrium  Right Ventricle  Pulmonary Trunk  Ductus Arteriosis  Aorta  Body

At birth or shortly thereafter ligamentum arteriosum ligamentum arteriosum

Anatomy of the Heart 1.Location and Size Pointed APEX -Pointed APEX - BASE -BASE -

2. Coverings and wall of the heart a. covered by double sac- PERICARDIUM Parietal Pericardium (pericardial fluid) Visceral Pericardium (outer layer heart) Myocardium Endocardium b. Layers of Heart Wall

C. Chambers of the Heart Two receiving chambers-Two receiving chambers- Two discharging chambers (pumps)-Two discharging chambers (pumps)- Right and left side separated by the – SEPTUMRight and left side separated by the – SEPTUM a. upper septum = b. lower septum = Atrium- Right Ventricle- Left Ventricle-

Cardiac Muscles (myocardium)

A Schematic

BLUE-pulmonary circuit RED- systemic circuitBLUE-pulmonary circuit RED- systemic circuit

Great Vessels of the Heart Pulmonary SystemicCircuit

Valves of the Heart Located at entrance/exit ventriclesLocated at entrance/exit ventricles Are 1-way, prevent back flow of bloodAre 1-way, prevent back flow of blood Atrioventricular-Atrioventricular- Semilunar-Semilunar-

Lubb Vs. Dupp

Cardiac Circulation Only the _________________ is in direct contact with the blood. Other heart tissue must have its own blood supplyOnly the _________________ is in direct contact with the blood. Other heart tissue must have its own blood supply CORONARY ARTERIESCORONARY ARTERIES CARDIAC VEINSCARDIAC VEINS

Conduction System of the Heart Cardiac muscles canCardiac muscles can ButBut Must have unifying control system to lend efficiency to the heart-Must have unifying control system to lend efficiency to the heart-1.2.a.b.c.

SA node () to the Atrial myocardium () to the AV node () to the AV bundle to the Bundle branches to the Purkinje fibers followed by Ventricular contraction ()

Electrocardiography “When impulses travel through the heart, electrical currents are generated that spread throughout the body. These impulses can be detected on the body surface and recorded with an electrocardiograph.

Electrocardiogram- recording that traces the flow of current through the heart.

P Wave-P Wave- QRS complex-QRS complex- T wave-T wave- *atrial repolarization

Cardiac Output- CO = Heart rate X Stroke Volume stroke volume- CO = 75 bpm X 70 ml/beat CO = 5250 ml/min (average)

What factors affect cardiac output?