aristotle galen of pergamum and pneuma zoticon
TRANSCRIPT
Aristotle
Galen of Pergamum and Pneuma Zoticon
DaVinci
WILLIAM HARVEY (1628)
How has the actual anatomy of the heart changed over time?
Open v. Closed Circulatory System
• OPEN• Pro: Simple• Con: Low Efficiency
• CLOSED• Pro: High Efficiency• Con: Complex Needs
Why Are Massive Insects Not Possible?
• Size of organism limited by type of circulatory system• Large organisms cannot survive
with open circulatory system due to limitations of the pumping apparatus
Evolution of The Heart
• Trend towards increased separation of oxygenated and deoxygenated blood• Increased separation of blood
facilitates increased activity, terrestrial lifestyle and homeothermic regulation
The Human Heart At Work
• 72 contractions/min = 2.5 billion/lifetime• 60,000 miles/day• 1.5 million gallons/lifetime• Enough energy expended in a lifetime to drive a pickup truck to the
moon and back
Orientation of Heart
• Size of fist? Depends upon age and health• Apex of heart (inferior tip) is just
superior to the diaphragm at the lower end of the thoracic cavity• Heart points sinister and 2/3rds
of heart mass is sinister to the midline
Pericardium
• Covers and nourishes the myocardium• Serous fluid-lubricates
heart/reduces friction
Anatomy of the Heart Wall
• Epicardium-Parietal layer of pericardium
• Myocardium – made of intercalated cardiomyocytes
• Endocardium-made of epithelial (skin) cells that prevent blood from sticking to inner wall (clotting)
Myocardial Thickness
• Right Side = thin• Blood only pumping to lungs or
right ventricle
• Left side = thick• Blood pumped to systemic
circulation and extremities
Atria (Auricles)
• Left Atrium• Receives deoxygenated blood
from body via vena cava
• Right Atrium• Receives oxygenated blood from
lungs via pulmonary vein/valve
Ventricles
• Right Ventricle• Receives blood from right atrium
• Left Ventricle• Receives blood from left atrium
Ventricular Septum
• Separates right and left ventricle• Prevents mixing of oxygenated
and deoxygenated blood
Cardiac Valves
• Function: to prevent the backwards flow of blood through coronary circulation
Atrioventricular Valves
• Tricuspid Valve• Separates right atrium from right
ventricle
• Bicuspid (Mitral) Valve• Separates left atrium from left
ventricle
Chordae Tendinae Cordis
• Tendons that open and shut the tricuspid and bicuspid valves• Attached to leaflets (valve flaps)
and anchored to epicardium covering the papillary muscles
Mitral Valve Prolapse
• Chordae tendinae fail to close the leaflets of the bicuspid valve• Blood regurgitates from the left
ventricle back into the left atrium
Semilunar Valves
• Crescent shaped cusps • Lack Chordae Tendinae/Closed by
Blood Pressure Alone• Valves located on structures ejecting
blood away from the heart• Pulmonary Semilunar Valve = right
atrium• Aortic Semilunar = left atrium
Coronary Circulation