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
In patients who have not received prior antibiotics and who will ultimately have blood culture positive endocarditis, it is likely that 95 - 100 per cent of all cultures obtained w


Define Sugar as a type of Carbohydrates? This group includes monosaccharide and disaccharides. List down the names of sugars under both these groups and check it out with those

Q. Determine the quality of various food grains? After undertaking this activity, you will be able to: • determine the various fractions involved with the physical examinati

describe sds page for the proteins

BLOO D PRESSURE Is the result of the sum of                 (i) Osmotic colloidal pressure of blood                 (ii) Elastic recoil of blood vessel's wall.

When a fatty acid reacts with glycerol, the result is- Select one: a. Formation of an amide b. Formation of an ester c. Formation of hydrocarbon d. Formation of a th

Antiviral activity

In 2003 nearly 70 million hectares globally were planted in genetically modi?ed crops. Of these, 73%  were plants such as soybean, corn and cotton, which were modi?ed to be he

Q. How do malign neoplasias appear? The Neoplasias appear due to DNA mutations in genes that regulate the cellular proliferation thus making the cell lose its capacity to contr