Circulatory System- the system that circulates blood and lymph through the body, consisting of the heart, blood vessels, blood, lymph, and the lymphatic vessels and glands
Here you will see... the numerous structures of the heart as well as the fetal circulatory system.
Pericardium- the membrane enclosing the heart, consisiting of an outer fibrous laer and an inner double layer of serous membrane
Apex- the muscular tip of the left ventricle
Ventricular Septum- muscular wall dividing the ventricles
The flow of blood through the heart: starting off with the vena cava, blood from the body enters through the vena cava into the right atrium, then flows to the right ventricle, which then pumps blood through the pulmonary artery to the lungs. Oxygenated blood then enters the left atrium via the pulmonary vein, then flows to the left ventricle where it will get pumped to the rest of the body through the aorta.
The Valves: prevent the backflow of blood, and ensures volumes are the same
Tricuspid Valve- (three flaps) between the right atrium and right ventricle
Bicuspid Valve- (two flaps) between left atrium and left ventricle
Semilunar Valves- pocket-like structures where pulomary artery and aorta leave the right and left ventricles
Contriubutions to Heart Contraction:
Papillary Muscles- located in the ventricles of the heart. Pull on Chordae Tendinae to prevent prolapsing of the AV valves
Chordae Tendinae- thread-like bands of fibrous tissue connected to papillary muscles. When the ventricle is pumping, these bands hold the AV valve in place
Fetal Circulation- Modifications to the circulatory system to allow the fetus to receive oxygenated blood and nutrients from the placenta.
Ductus Arteriosus- allows pulmonary artery to connect to aorta so it can head into circulation- bypassing the lungs
The fetus does not need to use its lungs so there is not a need for blood
Ductus Venosus- instead of pumping full supply of umbilical vein into the liver, bypass system allowing oxygenated blood to go directly into the blood
Nutreints from the placenta goes into the blood
Foramen Ovule- between left and right atrium, blood coming into right atrium moves directly into left atrium
Oxygenated blood is not sent to the lungs
Umbilical Vein- pure nutrient-rich blood from the placenta to the fetus
Umbilical Artery- deoxygentaed blood from fetus to the placenta