wk 4 -- Maternal

The decidua

— After fertilization, the corpus luteum in the ovary continues to function

— Uterine endometrium to grow thickness and vascularity

— Endometrium is now termed

Decidua vela

— uterine lining

Chorionic villi

— resemble probing fingers

— tiny projections of the placental tissue that contain the same genetic material

— Double layer of trophoblast cells surrounds these

11th-12th day

formation of placenta

The placenta

— Arising from the continuing growth of trophoblast tissue

— Covering half surface of uterus

— its growth parallels that of the tissues

50mL/min

(Rate of uteroplacental bloodflow

— 10 weeks

500mL - 600 mL / min

(Rate of uteroplacental blood flow)

— At term

Uterine perfusion

— Placental circulation

— most efficient on side lying position

— Lifts the uterus away from the inferior vena cava, preventing blood from being trapped in woman’s lower extremities

At term - Placenta

— Weighs 400-600 g (1Lbs)

Human chorionic gonadotropin

— First placental hormone produced

— Can be found in maternal blood and urine as early as the first missed menstrual period

— Testing for hCG after birth can be used as proof that placental tissue is no longer present.

Estrogen

— Hormone of women

— Contributes to the woman’s mammary gland development in preparation for lactation and stimulates uterine growth to accommodate the developing fetus

Progesterone

— Hormone of mothers

— Maintain the endometrial lining of the uterus during the pregnancy

—

Human Placental lactogen

— Hormone with both growth-promoting and lactogenic(milk-producing) properties

— Promotes mammary gland (breast) growth in preparation for lactation in the mother

— serves the important role of regulating maternal glucose, protein, and fat levels so that adequate amounts of these nutrients are always available to the fetus.

Gestational sac/Amniotic fluid

— Purpose is to form the sac that contains the amniotic fluid

— No nerve supply

— At birth can be seen covering the fetal surface of the placenta, giving that surface its typically shiny appearance

Amniotic fluid

— Constantly being newly formed and reabsorbed by he amniotic membrane, so it never becomes stagnant

— Fetus continually swallows the fluid

— Esophageal atresia or anencephaly are two common reasons why the fetus cannot swallow the fluid

Hydramnios

— Tends to occur in women with diabetes

— Hyperglycemia causes excessive fluid shifts into the amniotic space

Oligohydramnios

— Disturbance of kidney function

— Affects fetus movement due to low amniotic fluid

Umbilical c

Wharton’s jelly

— Bulk of the cord is a gelatinous mucopolysaccharide called

— Gives pressure the vein and arteries that pass through it

One vein

— Carrying blood from the placental villi to the fetus

Two arteries

— Carrying blood from the fetus back to the fetus back to the placental villi

8 weeks’ gestation

— End of the embryonic period

— All organ systems are complete

— The embryo will begin to develop at the point where the three cell layers (ectoderm, entoderm, and mesoderm) meet, called the embryonic shield

Ent

Endoderm

— Lower urinary system

Fetal circulation

— As early as the third eek of the intrauterine life, fetal blood begins to exchange nutrients with the maternal circulation across the chorionic villi

— Fetus derives oxygen and excretes carbon dioxide from gas exchange in the placenta

Fetal blood circulation

— Blood arriving to the fetus is highly oxygenated

— blood enters the fetus through the umbilical vein (carries oxygenated blood, toward the fetal heart)

End of 4th gestational eek

— ! month

— Embryo - rapidly growing cells

— Does not yet resemble a human being

End of 8th Gestational eek

— 2 months

— Facial features are now visible

— External genitalia are forming, but sex is not yet distinguishable

— Can now under go ultrasound

end of 12th gestational week

— First trimester - 3 months

—Movements present butt usually to faint to be felt

— Urine secretions begin

— Heartbeat audible through doppler technology

End of 16th gestational week

— 4 months

— Heart sounds audible by stethoscope

— Sex determined by ultrasound

— Fetus actively swallows amniotic fluid

End of 20th gestational week

— 5 months

— Movement sensed by mother

— Meconium is present in the upper intestine

— Brown fat - a special fat that will aid in temperature regulation at birth, begins to be formed behind the kidneys, sternum, and posterior neck.

— Vernix caseosa begin to form and cover the skin

Brown fat

— A special fat that will aid in temperature regulation at birth, begins to be formed behind the kidneys, sternum, and posterior neck

Meconium

— feces of fetus

end of 24th gestational week

— Second trimester - 6 months

— Can see and here

— Earliest age at which fetuses could survival if born a

32nd 8 months

End of 36th gestational week

— 9 Months

— Sole of the foot has only one or two crisscross crease

End of 40th gestational week

— Third trimester, 9 months

— Fetus kicks actively, hard enough to cuse the mother considerable discomfort