1080
UNIT 5
Continuity
28
Aortic arch
Fetus
Newborn
Superior vena cava
Ductus arteriosus
Ligamentum arteriosum
Lung
Pulmonary artery
Pulmonary veins
Heart
Foramen ovale
Fossa ovalis
Liver
Ductus venosus
Ligamentum venosum
Ligamentum teres
Umbilical vein
Inferior vena cava
Hepatic portal vein
Umbilicus
Abdominal aorta
Common iliac artery
Umbilical arteries
Medial umbilical ligaments
Urinary bladder
Umbilical cord
(a)
(b)
Placenta
High oxygenation
Moderate oxygenation
Low oxygenation
Very low oxygenation
Figure 28.14
Circulation in fetus and
newborn.
Arrows on blood vessels indicate
direction of blood flow. Arrows in color
screens go from the fetal structure to what it
becomes after birth.
(a)
Special adaptations
for embryonic and fetal life. The umbilical
vein carries oxygen- and nutrient-rich blood
from the placenta to the fetus. The umbilical
arteries carry waste-laden blood from the
fetus to the placenta. The ductus arteriosus
and foramen ovale bypass the nonfunctional
lungs. Note that blood passing through the
foramen ovale comes mostly from the inferior
vena cava. The ductus venosus allows blood
to partially bypass the liver.
(b)
Changes
in the cardiovascular system at birth. The
umbilical vessels as well as the liver and lung
bypasses are occluded.
previous page 1114 Human Anatomy and Physiology (9th ed ) 2012 read online next page 1116 Human Anatomy and Physiology (9th ed ) 2012 read online Home Toggle text on/off