Fetal Circulation (& Embryonic & Fetal Structures)

placenta and membranes

will serve as the fetal lungs, kidneys, and digestive tract in utero

human chorionic gonadotropin

• causes the uterine endometrium to continue to grow in thickness and vascularity instead of sloughing off as in a usual menstrual cycle

• secreted by the trophoblast cells

decidua

• sloughing off of the endometrium

• latin word for “falling off”

chorionic villi

• reach out from the trophoblast cells into the uterine endometrium to begin formation of placenta

• 12th or 12th day of fertilization

• have a central core consisting of connective tissue and fetal capillaries surrounded by a double layer of cells and produces hCG, somatomammotropin (human placental lactogen hPL), estrogen, and progesterone

cytotrophoblast or langhans layer

protect the growing embryo and fetus from certain infectious organisms (e.g., spirochete of syphilis)

placenta (latin for “pancake”)

grows from a few identifiable trophoblast cells at the beginning of pregnancy to an organ 15 to 20 cm in diameter 2-3 cm in depth

12th day

(what day) the pregnant patient’s blood begins to collect in the intervillous spaces of the uterine endometrium surrounding the chorionic villi

3rd week

(what week) oxygen, glucose, amino acids, fatty acids, minerals, vitamins, and water osmose from the maternal blood through the cell layers of the chorionic villi in the villi capillaries

Fetal Alcohol Syndrom (FAS)

more than 2oz daily of maternal alcohol ingestion

cotyledons

• compartments

• what make the maternal side of the placenta look rough and uneven

50, 10; 500, 600, term

rate of utero-placental blood flow in pregnancy increases from about ( ) ml per minute at ( ) weeks to ( ) to ( ) ml per minute at ( )

left side

uterine perfusion and placental circulation are most efficient when the pregnant lies on their __

vena cava syndrome

if a pregnant person lie on their back and the weight of the uterus compresses on the vena cava

400 to 600 g (1lb)

at term, the placental circulatory network has grown so extensively that a placenta weighs __

1. smaller placenta

2. bigger placenta

1. suggests circulation to the fetus have been compromised and/or inadequate

2. indicate circulation to the fetus was threatened - placenta was forced to spread out in an unusual manner to maintain a sufficient blood supply

syncytial (outer) layer of the chorionic villi

• hormone-producing system

• source of oxygen and nutrients for the fetus

human chorionic gonadotropin

• first placental hormone produced

• found in maternal blood and urine as early as the first missed menstrual period

• acts as a fail-safe measure to ensure the corpus luteum of the ovary continues to produce progesterone and estrogen so the endometrium of the uterus is maintained

• suppressing the maternal immunologic response so placental tissue is not detected and rejected as a foreign substance

progesterone

• “hormone that maintains pregnancy”

• necessary to maintain the endometrial lining of the uterus during pregnancy

• reduces the contractility of the uterus during pregnancy - preventing premature labor

estrogen

• for mammary gland development and stimulates uterine growth

human placental lactogen (human chorionic somatomammotropin)

• growth-promoting and lactogenic properties

• produced by 6th week pregnancy

• promotes breast growth

• important role for regulating parental glucose, protein, and fats level so adequate amounts of these nutrients are always available to the fetus

placental proteins

may contribute to decreasing the immunologic impact of the growing placenta; help prevent hypertension of pregnancy

1. chorionic membrane

2. amniotic membrane

1. outermost fetal membrane

2. forms beneath the chorion

   • a dual-walled sac

   • offers support to amniotic fluid and also produces the fluid

   • produces a phospholipid that initiates the formation of prostaglandins - the trigger that initiates labor

800 to 1200 ml

at term, the amount of amniotic fluid has grown so much it ranges from __

• esophageal atresia

• anencephaly

reasons the fetus is unable to swallow

1. hydramnios

2. oligohydramnios

1. more than 2000 ml in total or pockets of fluid larger than 8 cm on UZ

2. reduction in the amount of amniotic fluid

1. at least 5 cm

2. greater than 2 cm

3. about 7.2

4. 350 ml per minute at term

5. 53 cm (21 in.); 2 cm (0.75 in.)

1. amniotic fluid index (AFI) should be

2. vertical pocket of amniotic fluid should be

3. amniotic fluid pH level (slightly alkaline)

4. rate of blood flow through an umbilical cord

5. placenta length and thickness

amniotic fluid

• most important purpose: to shield the fetus against pressure or a blow to the pregnant person’s abdomen

• protects the fetus from changes in temperature

• aids in muscular development - because the fetus can move freely

• helps lung development

• protects the umbilical cord from pressure - protecting the fetal oxygen supply

umbilical cord

• formed from fetal membranes (chorion and amnion), and provides a circulatory pathway that connects the embryo to the chorionic villi of the placenta

• transport of oxygen and nutrients and pathway for return of waste products

Wharton jelly

• bulk of the cord; gelatinous polysaccharide

• gives the cord body

• prevents pressure on the vein and arteries that pass through it

blood velocity

adequacy of blood flow

1. hypocoiling

2. hypercoiling

1. maternal hypertension

2. respiratory distress in the newborn

nuchal cord

occurs when the umbilical cord wraps around a fetus's neck

1. totipotent stem cells

2. pluripotent stem cells

3. multipotent

1. at first 4 days of life, zygote cells are termed __ or cells that have the potential to grow into any cell in the human body

2. specific body cells; lost their ability to become any body cells

3. cells grow so specific they cannot be deterred from growing into a particular body organ

1. 10th to 12th

2. 11th; 20th

1. heartbeat can be heard on what week

2. electrocardiogram (ECG) may be recorded on a fetus as early as the ( ) week but the conduction is more regulated at about the ( ) week

liver, heart, kidneys, brain

the vital organs to be first supplied by blood are

ductus venosus

• an accessory vessel that discharges oxygenated blood into the fetal liver, and then connects to the fetal inferior vena cava so oxygenated blood is directed to the right side of the heart

foramen ovale

an atrial septum that connects the right atrium to the left atrium

ductus arteriosus

blood is shunted away from the lungs through __

1. 95-100%

2. 110-160 bpm

3. 17.1 per 100 ml

4. 53%

1. infant’s oxygen saturation level (range)

2. normal fetal heart rate

3. newborn’s hemoglobin level

4. newborn’s hematocrit

1. 3rd week of intrauterine life

2. end of 4th week

3. seventh week of life

respiratory system milestones:

1. the respiratory and digestive tract exists as a single tube

2. a septum begins to divide the esophagus from the trachea; lung buds appear on the trachea

3. the diaphragm does not completely divide the thoracic cavity from the abdomen

surfactant

• a phospholipid substance, formed and excreted by the alveolar cells

• decreases alveolar surface tension on expiration, preventing alveolar collapse and improving the infant’s ability to maintain respirations in the outside environment at birth

lecithin (chief component) and sphingomyelin

2 components of surfactant