Circulatory system - developmental changes, Biology

Circulatory System - Developmental Changes

We have learnt that throughout foetal life, gas exchange takes place, only through the placenta and not through lungs. Therefore, the foetus has various features in its circulatory systems that are not present in an adult. Diagram is a diagrammatic representation of foetal and infant circulation. In the foetus the oxygenated blood flowing back through the umbilical vein mainly bypasses the liver and goes to the right atrium.

2238_Circulatory System.png

Figure: Changes After Birth in Circulatory System

The blood then passes to the left atrium directly by an opening called foramen ovale. From the left atrium the blood flows to the left ventricle that sends the blood to the head and rest of the body. Blood returning from the head moves by the right atrium to the right ventricle which then does not pump the blood to the lungs but to a shunting vessel the ductus arteriosus that connects along with the descending aorta. A pair of umbilical arteries branch off from the aorta and carry deoxygenated blood to the placenta. At birth the umbilical artery and vein collapse while the cord is tied or the placenta separates, the result of it (here is negative pressure in the right atrium and blood flows back from the left atrium to the right. The flow causes the one way valve to close in the foramen ovale. Thus the left and right atria are separated. The shunting vessels which bypassed the liver and the lungs also collapse and adult pattern of circulation starts. The entire process takes place within a few hours of birth, though the permanent closure of foramen ovale may take up to a year.

Posted Date: 2/1/2013 3:18:15 AM | Location : United States







Related Discussions:- Circulatory system - developmental changes, Assignment Help, Ask Question on Circulatory system - developmental changes, Get Answer, Expert's Help, Circulatory system - developmental changes Discussions

Write discussion on Circulatory system - developmental changes
Your posts are moderated
Related Questions
what is the importance to study the tolerance range in real-life situations?

TYPES OF REGENERATION - R eparative R estorative 1. It is limited to healing of wounds or replacement of cells It can replace

Q. What are the cells that form the cartilaginous tissue? The main cells of the cartilages are the chondrocytes originated from the chondroblasts that secrete the intersticial

Hydrocolloids are extremely versatile and are used for many other purposes including: (a) Production of pseudoplasticity  (i.e. fluidity under shear) at high temperatures to ea

Explain the Magnesium Deficiency and Toxicity? Deficiency of magnesium is rare for two reasons: frstly, the mineral is widely distributed in the foods, secondly, kidney is able

Why does bark often break and die naturally? Bark is the mature periderm of the branches, stem and roots. It breaks and dies when these structures grow and thus the peridermal

Q. Etiological factor of diverticular disease? The causes of diverticular disease are not certain, but several factors may contribute to changes in the wall of the colon. These

Explain Precautions for Isolation of Pure Culture? 1. Plating of the medium should be done 24 hours before performing the streaking. There should not be any moisture on the

How is it produced and what is the function of cholecystokin in the digestive process? The fat level of the chyme detect in the duodenum stimulates the secretion of cholecystok

What is the group of aquatic beings composed of a large number of photosynthetic beings? A huge number of photosynthetic beings are found in the plankton that is in the surface