Circulatory System Lecture Guide
HISTORY OF THE CIRCULATORY SYSTEM: DISCOVERY OF THE BASICS
The most basic principles of the Circulatory system took thousands of years to uncover. An Egyptian papyrus dating back to
1500BC correctly correlated the character and frequency of the pulse with the patient’s health status. Hippocrates (460-355BC) and his pupils also drew accurate conclusions regarding the nature of blood flow.
The goal of this review is to examine the events that led to discovery of blood circulation. The Ancient Greeks, including Hippocrates and Galen viewed the cardiovascular system as comprising two distinct networks of arteries and veins. Galen claimed that the liver produced blood that was then distributed to the body in a centrifugal manner, whereas air was absorbed from the lung into the pulmonary veins and carried by arteries to the various tissues of the body. Arteries also contained blood. This was an open-ended system in which blood and air simply dissipated at the ends of veins and arteries according to the needs of the local tissue. Blood was not seen to circulate but rather to slowly ebb and flow. This view would hold sway for 15 centuries until 1628 when William Harvey published his momentous 72-page book, On the Motion of the Heart and Blood in Animals. Harvey employed experiment and deductive logic to show that arteries and veins are functionally, if not structurally, connected in the lung and the peripheral tissues, and that blood circulates. The mechanical force of the heart replaced Galen's elusive attractive powers.
PARTS OF THE CIRCULATORY SYSTEM
The heart, blood, and blood vessels make up the cardiovascular component of the circulatory system. It includes the pulmonary circulation, a "loop" through the lungs where blood is oxygenated. It also incorporates the systemic circulation, which runs through the rest of the body to provide oxygenated blood.
The Heart
-The Heart is an amazing organ. The heart beats about 3 BILLION times during an average lifetime.
The most basic principles of the Circulatory system took thousands of years to uncover. An Egyptian papyrus dating back to
1500BC correctly correlated the character and frequency of the pulse with the patient’s health status. Hippocrates (460-355BC) and his pupils also drew accurate conclusions regarding the nature of blood flow.
The goal of this review is to examine the events that led to discovery of blood circulation. The Ancient Greeks, including Hippocrates and Galen viewed the cardiovascular system as comprising two distinct networks of arteries and veins. Galen claimed that the liver produced blood that was then distributed to the body in a centrifugal manner, whereas air was absorbed from the lung into the pulmonary veins and carried by arteries to the various tissues of the body. Arteries also contained blood. This was an open-ended system in which blood and air simply dissipated at the ends of veins and arteries according to the needs of the local tissue. Blood was not seen to circulate but rather to slowly ebb and flow. This view would hold sway for 15 centuries until 1628 when William Harvey published his momentous 72-page book, On the Motion of the Heart and Blood in Animals. Harvey employed experiment and deductive logic to show that arteries and veins are functionally, if not structurally, connected in the lung and the peripheral tissues, and that blood circulates. The mechanical force of the heart replaced Galen's elusive attractive powers.
PARTS OF THE CIRCULATORY SYSTEM
The heart, blood, and blood vessels make up the cardiovascular component of the circulatory system. It includes the pulmonary circulation, a "loop" through the lungs where blood is oxygenated. It also incorporates the systemic circulation, which runs through the rest of the body to provide oxygenated blood.
The Heart
-The Heart is an amazing organ. The heart beats about 3 BILLION times during an average lifetime.