Transcript Patent Ductus Arteriosus

TOPIC 2
Group A
Heart
• The heart pumps blood
throughout the entire
body
• The heart beats
approximately 72 beats
per minute supplying cells
of the body with nutrients
they need to survive
• When looking at an
image, the right and
left are defined as the
right and left of the
patient.
• This means right and
left are reversed when
looking at an image.
• In this image of the
heart, “right” is to the
left of the image and
“left” is to the right of
the image.
RIGHT
LEFT
The Heart Contains
Four Compartments:
2 Atrial
and
2 Ventricular
Compartments
Atrial Compartments of the Heart
The atria of the heart are
receiving chambers. The
right atrium receives blood
from the body via the
superior and inferior vena
cava and the left atrium
receives blood from the
lungs via the pulmonary
veins.
Pectinate
Muscle
Right
Atrium
The atrial chambers contain pectinate
muscles within the walls of the chamber.
Blood passes from the atria to the ventricles
through a one-way opening called the
atrioventricular valve.
Atrial
Compartments
Ventricular Compartments of the Heart
The ventricles are the discharging
chambers. The right ventricle pumps
blood away from the heart to the lungs
via the pulmonary arteries and the left
ventricle pumps blood away from the
heart to the body through the aorta.
Right
Ventricl
e
The ventricular chambers contain
trabeculae carneae muscle. Ventricular
chambers are more muscular and larger
in size because they must pump blood
away from the heart into a system under
higher pressure, the pulmonary arteries
or aorta. The left ventricle is the most
muscular since it functions to pump
blood to the entire body via the aorta.
Trabeculae
Carneae
Muscle
Ventricular
Compartments
As blood fills the atria, the
pressure rises and forces the blood
into the ventricles through the
one-way atrioventricular valve.
The period of ventricular filling is
called diastole in the cardiac
cycle. When a physician listens
with a stethoscope, the ventricle
filling with blood sounds like a
“lub”.
When the ventricles fill, an
electrical impulse signals them to
contract to push the blood into the
pulmonary artery (right ventricle)
or into the aorta (left ventricle).
This period of ventricular
contraction is called systole in the
cardiac cycle. When a physician
listens with a stethoscope, the
ventricle squeezing blood out of
the heard sounds like a “dub”.
To listen to heart sounds that determine
healthy heart function, a physician places a
stethoscope on the chest wall during an
examination.
The physician locates the intercostal spaces,
or spaces between the ribs, where certain
structures pertaining to heart function can be
heard.
This image of the anterior chest wall
demonstrates stethoscope placements:
1= At the 2nd intercostal space, to the right of
the midline, one can hear the blood in the
aorta as it leaves the heart.
2= At the 2nd intercostal space, to the left of
the midline, one can hear the blood in the
pulmonary trunk as it leaves the heart.
3=At the 3rd through 5th intercostal spaces, just
to the left of the midline, one listens for proper
function of the right ventricle.
4=At the 5th intercostal space, far left of the
midline, one listens for proper function of the
left ventricle.
If one imagines the heart in place
under the thoracic wall, the same
stethoscope placements viewed
in the previous slide can be
correlated with blood flow through
anatomically important structures
of the heart.
1= Blood flow into the aorta can
be heard.
2= Blood flow into the pulmonary
trunk can be heard.
3= Blood flow between the right
atrium and right ventricle, through
the tricuspid valve, can be heard.
4= Blood flow between the left
atrium and left ventricle, through
the mitral valve, can be heard.
Blood flow in the Fetal Heart Differs from
Blood Flow in the Heart after Birth
VS.
Right
Atrium
Pulmonary
Artery
Right
Ventricle
Aorta
To the Body
Left
Atrium
Left
Ventricle
Normally blood flows from
the right side of the heart to
the left. Deoxygenated blood
enters the right atrium then
right ventricle. Blood travels
to the lungs through the
pulmonary artery to become
oxygenated. The left atrium
then receives the oxygenated
blood. After passing through
the left atrium, blood travels
to the left ventricle and then
to the aorta, and finally out
to the body. However, in
fetal circulation, blood in
the heart is shunted away
from the lungs.
Blood flow within the fetal heart is very similar to blood flow in the heart
after birth. However, within the fetal circulation there are two shunts that
direct blood flow away from the lungs. Blood must bypass the lungs
because prior to birth the fetal lungs are not fully developed. These shunts
are known as the foramen ovale and the ductus arteriosus. The
foramen ovale is an opening located in the right atrium. This opening
allows blood to be shunted from the right atrium directly to the left atrium
and away from the fetal lungs. The ductus arteriosus is a vascular
connection found directly between the pulmonary artery and the aorta.
Blood is shunted from the pulmonary artery directly into the aorta and again
away from the fetal lungs. The fetus is connected by the umbilical cord to
the placenta of the mother. Oxygen and carbon dioxide exchange takes
place at the placenta along with the elimination of waste products.
Ductus
Arteriosus
Foramen
Ovale
Typically, the foramen ovale and ductus arteriosus close following
birth, thus altering the circulatory system. Blood begins to move from the right
atrium to the left atrium and then to the lungs for the exchange of oxygen and
carbon dioxide and the newborn begins to breath on its own. However, in some
cases either of the two shunts may not close leading to health complications.
The foramen ovale is initially closed by a flap. The pressure in the left atrium
prevents the flap from opening. Eventually the flap seals closed so that the
foramen ovale opening in the fetus becomes the fossa ovale depression in heart
after birth.
If the flap forms incompletely or
does not completely seal close,
then deoxygenated blood can
pass from the right atrium to the
left atrium. A patient with an
open or patent foramen ovale
will have a heart murmur.
Unfortunately, this heart
murmur maybe undetectable and
the patient will exhibit no other
obvious symptoms.
Patent Ductus Arteriosus
If the ductus arteriosus remains open after birth and
fails to close it is referred to as a patent ductus
arteriosus. The term “patent” means open.
Complications associated with patent ductus
arteriosus are poor growth and eating, easy tiring,
and a rapid heart rate. It is also common to notice
that the infant is blue in color, especially while
feeding, due to a lack of oxygen.