Circulatory system - developmental changes, Biology

Assignment Help:

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.


Related Discussions:- Circulatory system - developmental changes

Specie concept, what is nomenalistic specie concept

what is nomenalistic specie concept

What is meant by binomial nomenclature, What is meant by binomial nomenclat...

What is meant by binomial nomenclature and what are its basic rules? Scientific nomenclature of a species must have, at least, two names: one that classifies it as genus and th

What is hyperhomocysteinaemia, What is Hyperhomocysteinaemia ? Homocyst...

What is Hyperhomocysteinaemia ? Homocysteine has been considered as a risk factor for Cardio-vascular diseases because of many epidemiological and observational studies showing

Barrier function of epithelium and endothelium in corneal, Explain about th...

Explain about the barrier function of epithelium and endothelium in corneal hydration. Barrier Function of Epithelium and Endothelium: Epithelium offers twice the resista

Explain microtube and hedstorm file removal technique, Explain Microtube an...

Explain Microtube and Hedstorm file removal technique A Hedstorm file was then passed down the length of the tube until it engaged itself tightly between the obstruction an

Show the process of construction of keys, Q. Show the process of Constructi...

Q. Show the process of Construction of Keys? Keys are constructed using contrasting characters. The possible names in the key are divided into smaller and smaller groups. Each

Baby delivery, some deliveries of baby occur early na. y is it so?

some deliveries of baby occur early na. y is it so?

Use of genital herpes in pregnancy, Use of genital herpes in pregnancy ...

Use of genital herpes in pregnancy Although acyclovir is not approved for treatment of pregnant women, its use during pregnancy has not been associated with an increased risk

Pericardium, The heart is enclosed in a membranous sac called the pericardi...

The heart is enclosed in a membranous sac called the pericardium. It has two layers- the fibrous pericardium which is the outer layer and the serous pericardium that lies inside th

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd