vitelline circulation

Examples of vitelline circulation in the following topics:

• Yolk Sac Development

  • After circulating through a wide-meshed capillary plexus, it is returned by the vitelline veins to the tubular heart of the embryo.
  • This vitelline circulation absorbs nutritive material from the yolk sac that is conveyed to the embryo.
  • At the end of the fourth week, the yolk sac has the appearance of a small, pear-shaped vesicle (umbilical vesicle) opening into the digestive tube by a long, narrow tube, the vitelline duct.
  • As a rule, the vitelline duct undergoes complete obliteration during the seventh week.

• Sinusoid Development

  • The vitelline veins drain blood from the yolk sac.
  • The invasion of endometrial sinusoids by the trophoblast allows maternal blood flow into the trophoblastic lacunae; this forms the uteroplacental blood circulation.
  • (The vitelline veins are visible at the center bottom.)

• Development of the Heart

  • The ventral branches of the aorta consist of the vitelline arteries and umbilical arteries.
  • The vitelline arteries form the celiac, superior, and inferior mesenteric arteries of the gastrointestinal tract.
  • The human venous system develops mainly from the vitelline veins, the umbilical veins, and the cardinal veins, all of which empty into the sinus venosus.

• Systemic and Pulmonary Circulation

  • The cardiovascular system has two distinct circulatory paths, pulmonary circulation and systemic circulation.
  • From the left ventricle, the blood is pumped through the aortic valve into the aorta to travel through systemic circulation, delivering oxygenated blood to the body before returning again to the pulmonary circulation.
  • From the right atrium, the blood will travel through the pulmonary circulation to be oxygenated before returning gain to the system circulation.
  • Coronary circulation, blood supply to the heart muscle itself, is also part of the systemic circulation.
  • Diagram of pulmonary circulation.

• Blood Supply to the Lungs

  • Pulmonary circulation refers to blood supply to the lungs for the purpose of gas exchange.
  • Bronchial circulation (by the bronchial arteries) supplies blood to the tissues of the bronchi and the pleura, and is considered part of systemic circulation.
  • The right side of the heart deals with pulmonary circulation.
  • Systemic circulation and pulmonary circulation form the overall cycle of the circulatory system: transporting oxygen throughout the body.
  • Diagram of pulmonary circulation.

• Development of Metabolism

  • The yolk sac remains connected to the gut tube via the vitelline duct.

• Development of the Cardiovascular System

  • Finally, the ventral branches of the aorta consist of the vitelline arteries and umbilical arteries.
  • The vitelline arteries form the celiac, and superior and inferior mesenteric arteries of the gastrointestinal tract.
  • The human venous system develops mainly from the vitelline,umbilical, and cardinal veins, all of which empty into the sinus venosus.

• Fetal Circulation

  • Fetal circulation includes the blood vessels within the placenta and the umbilical cord that carry fetal blood.
  • Fetal circulation is the circulatory system 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 fetal circulation works differently from that of born humans, mainly because the lungs are not in use.
  • 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 circulatory system to the fetus.
  • These closures prevent blood from bypassing pulmonary circulation, and therefore allow the neonate's blood to become oxygenated in the newly operational lungs.

• Fourth Week of Development

  • At the end of the fourth week the yolk sac presents the appearance of a small pear-shaped vesicle (the umbilical vesicle) opening into the digestive tube by a long narrow tube, the vitelline duct.

• Digestive System Development

  • The yolk sac remains connected to the gut tube via the vitelline duct.