Download Fetal circulation By

Fetal circulation
By:
Asmaa mashhour eid
Supervised:
Dr Aida abd-alrazk
Objective:
1-summarize anatomuy
cardiovascular fetus
2-explian what heart rate fetus
affected
3-define different aspects in fetal
circulation
4-explain fetal circulation
intrauterine
5-explain fetal circulation
extrauterine
6-describ fetal hemoglobin and
differs from adult
7-summary
8-referans
Cardiovascular system
-first systems become functional in
intrauterine life
-simple blood cell joined to the
walls of the yolk sac progress to
become a network of blood vessels
and single heart tube which forms
as early as the 16th of day of life
Cont
-heart beats as early as the 24th
day
-heart divides four chambers 6th
th
or 7 week (two atrium and two
ventricle )
-heart begin to develop in the 7th
week
Fetal circulation intrauterine
-umbilical vein transports
blood rich in O2 and nutrients
from the placenta to the fetal
body
-This divides into two inside the
body of the fetus
1-one branch goes to the liver
2- other called ductus venosus
-ductus venosus joins inferior
vena cava, which carries
deoxygenated blood to the right
atrium
-As the blood from the inferior
vena cava enters the right
atrium, a large proportion of it is
shunted directly into the left
atrium through an opening
called the foramen ovale.
-the foramen ovale helps
prevent blood from moving in
the reverse direction
-The right atrium also receives
deoxygenated blood from the
upper parts of the body through
the superior vena cava
-enters the right ventricle and
then pumped into the pulmonary
artery.
-. In the fetus the pulmonary
artery is connected to the
descending aorta by a blood
vessel called ductus arteriosus
-Most of the blood in the
pulmonary artery bypasses the
lungs by entering a fetal vessel
the ductus arteriosus
-Because there is no point in
pumping blood into the lungs most
of the blood in the pulmonary artery
in shunted across the ductus
arteriosus into the aorta
-This blood contains less oxygen
than that pumped by the left
ventricle and supplies the lower
parts of the body
-The umbilical cord also
contains two umbilical arteries.
These arteries contain
deoxygenated blood from the
fetus into the placenta
completing the cycle.
Fetal circulation extrauterine
-after birth the umbilical cord is
clamped and cut
-Inflation of the lungs reduces the
resistance to blood flow through the
lungs resulting in increases blood
flow from the pulmonary arteries
-an increased amount of blood
flows from the right atrium to
the right ventricle and into the
pulmonary arteries and less
blood flows through the foramen
ovale to the left atrium
-increased volume of blood
returns from the lungs through
the pulmonary veins to the left
atrium, which increases the
pressure in the left atrium.
-ductus arteriosus starts
shrinking and functionally closes
by about 72 hours of life and
anatomically closes within a few
weeks
Heart rate fetal affected:
1-fetal oxygen level
2-body activity
3-circulation blood volume
Fetal hemoglobin
-The concentration of
hemoglobin in fetal blood is
about 50 % greater than in
maternal blood.
-Fetal hemoglobin is slightly
different chemically and has a
greater affinity for O2 than
maternal hemoglobin.
-fetal hemoglobin can carry 2030% more O2 than maternal
hemoglobin
Difference between fetal and
adult hemoglobin
* fetal hemoglobin composition
(two alpha and two gamma
chains)
Cont
*adult hemoglobin composition
(two alpha and beta)
* hemoglobin form at birth that
newborn about (17g/100 ml)
* adult hemoglobin normal level
(11g/100ml)
Cont
*fetal hematocrit is about 53%
* adult hematocrit about 45%
Summary:
- fetal circulation difference about
adult circulation
- fetal circulation intrauterine
depend on mother
- fetal circulation extrauterine
develop gradually
- fetal hemoglobin difference adult
hemoglobin
Reference:
1- Book (maternal and child health
nursing)
fifth edition
(Adele pillitteri)
pages (190 ,191,191)
2- internet
www.homebusinessandfamilylife.co
m