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

Show the structures of human auditory sensitivity, Q. What are the structur...

Q. What are the structures that participate in the human auditory sensitivity? The structures of the human auditory sensitivity are the ears (middle and internal, external) the

Plant responses to light-dark cycles, Plant Responses to Light-Dark Cycles ...

Plant Responses to Light-Dark Cycles Based on their requirement for day length (number of hours of light) for flowering plants have been grouped under three major categories,

What are polysaccharides, What are Polysaccharides? Polymers of simple ...

What are Polysaccharides? Polymers of simple sugars are known as Polysaccharides. Several polysaccharides, unlike sugars, are insoluble in water. Dietary fibre includes polysac

Soil texture and structure, SOIL TEXTURE AND STRUCTURE We have seen that ...

SOIL TEXTURE AND STRUCTURE We have seen that soils are predominantly composed of particles of various sizes derived from the disintegration or decomposition of parent rock materi

Enumerate the history of neuropsychological, Enumerate the history of neuro...

Enumerate the history of neuropsychological The typical neuropsychological exam begins with a careful history taking. Areas of interest include: Medical history of patie

Define water losses by intestine and lungs, Define water losses by Intestin...

Define water losses by Intestine and Lungs? Intestine : A small quantity of water (about 100-200 ml) is normally lost in faeces, but this can exceed 5 L in diarrhoeal episodes

What is light reaction, What is light reaction? Light reactions are rea...

What is light reaction? Light reactions are reactions, which are initiated by light (also photo-induced reactions). Usually, light energy is change into chemical energy.

Prodigality of nature, By prodigality of nature it is meant that organisms ...

By prodigality of nature it is meant that organisms have an enormous potential to reproduce. A carp or salmon is known to lay over a million eggs. A frog may lay Bs many as 12,000

Jaundice (icterus), Jaundice (Icterus) Jaundice is classified as pre-he...

Jaundice (Icterus) Jaundice is classified as pre-hepatic (hemolytic), hepatic and post-hepatic (obstructive) depending on origin of the problem, and is characterized by yellowi

Define criteria for assessment of riboflavin status, Define Criteria for As...

Define Criteria for Assessment of Riboflavin Status? Riboflavin status can be assessed by measuring urinary excretion of the vitamin in fasting, random, and 24-hour specimens o

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