HUMAN A&P: MODULE 06.05 FETAL CIRCULATION

Mrs. Jessica Romito

SUMMARY

Review module

• 06.05 Fetal Circulation

Review worksheet

• 06.05 page 2 Fetal Circulation Video Worksheet

Review assessment

• 06.05 Fetal Circulation Chart

OBJECTIVES

By the end of this iClass, you will to be able to:

• Compare and contrast fetal circulation before and after birth
• Find the information to complete the course worksheet and review the completed worksheet
• Understand the expectations for the module assessments

STANDARDS

SC.912.L.16.13: Describe the basic anatomy and physiology of the human reproductive system. Describe the process of human development from fertilization to birth and major changes that occur in each trimester of pregnancy.

FEMALE REPRODUCTIVE SYSTEM

Label the parts

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A OVARIES where eggs are produced

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B FALLOPIAN TUBE (OVIDUCT) how the egg travels from the ovary to the uterus

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C UTERUS where a fetus develops

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D VAGINA opening leading to the outside of the body

A

B

C

REVIEW

A

B

C

FETAL DEVELOPMENT: 1^ST TRIMESTER (month 2)

1. Neurulation is the first step in the development of the nervous system.
• Part of the ectoderm thickens and folds to form a neural tube that eventually develops into the brain and spinal cord.
2. Specialized membranes form to protect and nourish the growing embryo.
1. A sac filled with amniotic fluid surrounds the embryo to cushion and protect it.
2. Other membranes form the placenta to connect the embryo to the mother.
• It is through this one organ that the fetus receives its oxygen and nutrients and disposes of its wastes.

REVIEW

FETAL DEVELOPMENT: 1^ST TRIMESTER (month 3)

After eight weeks of development, the embryo is called a fetus.

After three months of development, most of the major organs of the fetus are fully formed.

• However, most of the tissues and organs are not ready to function on their own.
• The fetus is about eight centimeters long and can move and show signs of reflexes.

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REVIEW

FETAL DEVELOPMENT: 2^ND TRIMESTER (months 4 through 6)

• Tissues become more specialized and begin to function.
• The heart is now large enough for heartbeats to be heard with a stethoscope.
• Bone starts to replace cartilage to form the early skeleton, and the mother begins to feel the fetus moving.
• Around week 13, the fetus's intestines return to its abdomen from the umbilical cord, where they've been growing for the past couple of weeks.

REVIEW

FETAL DEVELOPMENT: 3^RD TRIMESTER (months 7 and 8)

• The lungs and other organs continue to develop and prepare for life outside of the uterus.
• The lungs are still developing until shortly before birth, but rhythmic breathing movements begin before the lungs are fully developed.
• It usually takes nine months for a fetus to fully develop; babies born earlier than eight months are considered premature and may have incomplete lung development.

REVIEW

FETAL CIRCULATION VIDEO

• HOW DOES A BABY GET WHAT IT NEEDS?
• Umbilical cord and placenta
• The umbilical cord forms from the baby’s abdomen when he’s just a tiny embryo.
• The cord contains one vein that sends oxygenated blood into baby’s body, and two arteries that remove the deoxygenated blood.”

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FETAL CIRCULATION VIDEO

• The cord contains one vein that sends oxygenated blood into baby’s body, and two arteries that remove the deoxygenated blood.”
• The vein passes into the fetus’ inferior vena cava by way of a special vessel called the ductus venosus.
• Then the oxygenated blood enters the heart, which pumps it to the head and upper extremities.
• When blood returns to the heart, a portion of it flows into the lungs
• The lungs don’t have any oxygen for baby yet,
• The largest fraction of blood flows through the ductus arteriosus,
• Down to the baby’s lower extremities and into the two arteries of his cord

FETAL CIRCULATION VIDEO

• The two arteries out of baby’s body through his cord come to the source of all of baby’s oxygen, nutrients, and waste disposal — the placenta
• The blood of the umbilical cord moves into smaller blood vessels that lie within the villi of the placenta.
• Since the placenta is attached to the mother, maternal blood can fill the spaces that surround the villi.
• Oxygen, carbon dioxide, nutrients, and wastes can diffuse through the villi tissues and transfer between the mother’s blood and the blood vessels of the baby.
• The mother’s veins carry carbon dioxide and wastes away from the placenta.
• The cord carries the nutrients and oxygen back to the baby.

FETAL CIRCULATION VIDEO

• Mother’s blood and baby’s blood never mix in the placenta.
• The mother’s blood contains immune system substances that would recognize the baby’s blood as something alien and launch an attack. The protective barriers of the villi tissues prevent this from happening

FETAL CIRCULATION VIDEO

• When the baby takes his first breath and his umbilical cord is cut, the blood pressures in various sections of his vascular system change.
• This change in pressure causes the ductus venosus and the ductus arteriosus to eventually close off.
• The blood is redirected to the lungs to receive oxygen and release carbon dioxide.

FETAL CIRCULATION VIDEO WORKSHEET

1. The umbilical cord forms from the baby’s ABDOMEN when he's just a tiny embryo.
2. The umbilical cord contains one vein that sends OXYGENATED blood into baby's body, and two arteries that remove the DEOXYGENATED blood.
3. The umbilical vein of the baby's cord passes into his inferior vena cava by way of a special vessel called the DUCTUS VENOSUS.
4. When blood returns to the heart, a portion of it flows into the lungs, but the largest fraction of blood flows through the DUCTUS ARTERIOSUS, down to the baby's lower extremities, and into the two ARTERIES of his cord.
5. The source of all of baby's oxygen, nutrients, and waste disposal is the PLACENTA.
6. The blood of the umbilical cord moves into smaller blood vessels that lie within the VILLI of the placenta.

FETAL CIRCULATION VIDEO WORKSHEET

7. Oxygen, carbon dioxide, nutrients, and wastes can DIFFUSE through the villi tissues and transfer between the mother's blood and the blood vessels of the baby.
8. The mother’s VEINS carry carbon dioxide and wastes away from the placenta.
9. The UMBILICAL CORD carries the nutrients and oxygen back to the baby.
10. Mother's blood and baby's blood NEVER mix in the placenta. The mother's blood contains immune system substances that would recognize the baby's blood as something alien.
11. When baby takes his first breath and his umbilical cord is cut, the BLOOD PRESSURES in various sections of his vascular system change. This change causes the ductus venosus and the ductus arteriosus to CLOSE.
12. The blood is redirected to the LUNGS to receive oxygen and release carbon dioxide.

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ASSESSMENT 06.05

• Using your knowledge of fetal circulation, and the respiratory and digestive systems, fill in the chart provided.
• It compares and contrasts fetal circulation and circulation after birth.
• A sample box has been filled in for you.
• Submit a copy of your chart to the assessment area under 06.05 Fetal Circulation.

Contact Information

Mrs. Jessica Romito

Phone Number: (301) 485-9114

Time Zone: Eastern

Email: jromito@laurelsprings.com

Mrs. Romito's iClassroom

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Monday–Friday 8 am to 11 pm Eastern Time�5 am to 8 pm Pacific Time

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