ALLANTOIC CIRCULATION Meaning and
Definition
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Allantoic circulation refers to the system of blood vessels that supplies and circulates blood within the allantois, a membranous sac found in the embryos of reptiles, birds, and mammals. It is an important feature of embryonic development and plays a crucial role in the exchange of nutrients, gases, and waste products between the embryo and its environment.
The allantois is an outgrowth of the hindgut and serves as a storage site for waste material, primarily uric acid, during early embryonic stages. It eventually fuses with the chorion to form the chorioallantoic membrane, which serves as the primary organ of respiration and nutrient exchange. The allantoic circulation is responsible for maintaining the viability and development of the embryo by delivering oxygen and nutrients and removing carbon dioxide and metabolic waste products.
The circulation within the allantoic blood vessels is typically organized into two major vessels: the allantoic artery and allantoic vein. The allantoic artery is responsible for carrying oxygenated blood from the developing embryo to the chorioallantoic membrane, where gas exchange occurs. This oxygenated blood is then transported back to the embryo through the allantoic vein, which carries deoxygenated blood. The process of exchange is facilitated by the thin-walled blood vessels and close proximity between the allantois and the chorioallantoic membrane.
Overall, allantoic circulation is a vital component of embryonic development, ensuring proper oxygenation, nutrient supply, and waste removal necessary for the growth and survival of the embryo.
Etymology of ALLANTOIC CIRCULATION
The word "allantoic circulation" can be broken down into two parts:
1. Allantoic: The term "allantoic" is derived from the Latin word "allantois", which refers to a membranous sac found in the developing embryos of reptiles, birds, and mammals. The allantois functions as a site for waste disposal and gas exchange.
2. Circulation: The word "circulation" comes from the Latin word "circulatio", which means "a circular course", or "movement in a circle". In biology and physiology, the term is commonly used to describe the movement or flow of fluids, such as blood or lymph, through a system of vessels or channels.
Therefore, "allantoic circulation" refers to the movement or flow of fluids through the vessels associated with the allantois, specifically in the context of embryonic development.
