The fetal circulation is the circulatorysystem of a human fetus, often encompassing the entire fetoplacental circulation that also includes the umbilical cord and the blood vessels within the placenta that carry fetal blood .
The core concept behind fetal circulation is that fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin, which allows a diffusion of oxygen from the mother's circulatorysystem to the fetus.
The circulatorysystem of the mother is not directly connected to that of the fetus, so the placenta functions as the respiratory center for the fetus as well as a site of filtration for plasma nutrients and wastes.
The circulatorysystem is extremely important for sustaining life.
Its proper functioning is responsible for the delivery of oxygen and nutrients to all cells and tissues, as well as the removal of carbon dioxide and waste products, maintenance of optimum pH, and the mobility of the elements, proteins and cells of the immune system.
In developed countries, the two leading causes of death, myocardial infarction and stroke, each may directly result from an arterial system that has been slowly and progressively compromised by years of deterioration.
The arterial system is the higher-pressure portion of the circulatorysystem.
The pressure in the arterial system decreases steadily, being highest in the aorta and lowest in the venous system, as blood approaches the heart after delivery of oxygen to tissues in the systemic circulation.
The lymphatic system is a part of the circulatorysystem, comprising a network of conduits called lymphatic vessels that carry a clear fluid (lymph), unidirectionally towards the heart.
The lymph system is not a closed one.
The circulatorysystem processes an average of 20 liters of blood per day through capillary filtration which removes plasma while leaving the blood cells.
Secondly, the lymphatic organs play an important part in the immune system, having a considerable overlap with the lymphoid system.
The system also includes all the structures dedicated to the circulation and production of lymphocytes, which includes the spleen, thymus, bone marrow, and the lymphoid follicles associated with the digestive system, such as the tonsils.
The lymphatic system comprises a network of conduits called lymphatic vessels that carry lymph unidirectionally towards the heart.