Anatomy and Major function of Circulatory System

Circulatory system consists of 2 circuits: Pulmonary – heart to lungs; Systemic – heart to rest of body
(left A/V = oxygenated; Right A/V = deoxygenated)

Pericardial Cavity – space b/w thoracic cavity and the heart to ensure it properly perform all its functions
At Left Atrium:
Pulmonary Trunk
Aorta  ascending, arch, and descending; arch has 3 exits: Brachiocephalic Trunk, Left Carotid, Subclavian
Left & Right Pulmonary Arteries carry blood to the lungs
Left & Right pulmonary Veins; 2 pairs – bring blood back from the lungs (**Heart attack when they get clogged)
At Right Atrium:
Superior Vena Cava & Inferior Vena Cava – bring blood back to heart from systemic circuit

Heart Atrias and Ventricles are separated by the ‘Interventricular Septum’ and the ‘Interatrial Septum’
AV valves b/w atria and ventricles called ‘bicuspid’ or ‘Tricuspid’ valves; held by ‘chordae tendinae and Papillary muscles, act like a parachute to ensure the valve doesn’t flip back out.
Pulmonary trunk seperated from the ventricles are called Pulmonary ‘semilunar’ valves (bulgy half moons)
Right Ventricle wall is thinner than Left Ventricle wall due to Pressure differences.
Valves
Right AV = tricuspid; Left AV = Bicuspid
The Aortic and Pulmonary ‘semilunar’ valves are much tighter w/ a Y-shaped edge
Contraction of papillary muscles prevent AV-valves from backflow by holding chordae tendineae tightly
Valves are also found in the Venous system  in the Legs, muscle contraction open/closes valves to prevent backflow of blood
Cardiac Cycle [20-16, 20-17]
Staggered cycle of compression and relaxation aids in pushing the blood through ventricles and atrias
Atrial Systole forces blood into ventricle >