Lab 7 (PT. 2 Fetal Circulation ): Cardiovascular System & Lymphatic system

Trace Fetal Circulation

1. Nutrient & gas exchange occurs via placenta, diffusing from maternal to fetal blood

2. 2 umbilical arteries carry deoxygenated blood to the placenta while the umbilical vein carries oxygen & nutrients to the fetus

3. Most blood enters the inferior vena cava via the ductus venosus; oxygenated mixes w/ deoxygenated & returns to the right atrium

4. Most of the blood in the right atrium passes through the foramen ovale into the left atrium & the left ventricle pumps blood out the aorta.

5. Instead of through the pulmonary trunk, blood in the right ventricle passes through the ductus anteriosus into the aorta

6. blood in the systemic system flows into the umbilical arteries & back to the placenta

name the opening in the fetal interatrial septum

foramen ovale

placenta description & function

description:

• temporary, disc-shaped organ that forms during pregancy

• attached to the uterine wall & connects to the fetus via the umbilical cord

function:

• gas exchange

• nutrient delivery

• waste removal

• hormone production

• immune protection (passes maternal antibodies to the fetus, blocking pathogens)

umbilical arteries description & function

description:

• fetal blood vessels running through the umbilical cord to the placenta

function:

• transport deoxygenated fetal waste (CO2, urea) to placenta for mother’s circulation

now:

• medial umbilical ligament

umbilical vein description & function

description:

• fetal blood vessel running through the umbilical cord

function:

• delivers O2 rish, nutrient-rich blood from the placenta to the fetus via the ductus venosus

now:

• ligamentum teres

ductus venosus description & function

description:

• shunt that connects the umbilical vein to the inferior vena cava

• bypasses fetal liver, allowing most of the blood to flow to heart & brain

function:

• oxygen priorty of brain and heart

  • liver bypass (prevents nutrient/toxin overload in immature liver)

now:

• ligamentum venosus

foramen ovale description & function

description:

function:

now:

• fossa ovalis

ductus arteriosus description & function

description:

• shunt; flap-like opening in the interatrial septum that acts as a one-way valve permitting blood from right atrium → left atrium

function:

• redirects O2 blood away from lungs into systemic circulation

now:

• ligamentum arteriosum