107 LEC - Human Development

Amniotic Fluid

Water-like substance inside the uterus that protects the fetus from injury and temperature changes.

Amniotic Membrane

The membrane that forms and reabsorbs the amniotic fluid.

800 - 1200 mL

Amount of amniotic fluid in full term.

7.2 pH

pH level of amniotic fluid.

Umbilical Cord

A fetal structure that provides a circulatory pathway that connects the embryo to the placenta.

Funis

The medical terminology for the umbilical cord.

Fetal Membrane

The membrane where the umbilical cord forms from.

2

Number of arteries in the umbilical cord.

1

Number of veins in the umbilical cord.

Vein

A blood vessel of the umbilical cord that carries oxygenated blood.

Artery

A blood vessel of the umbilical cord that carries deoxygenated blood.

53 cm

Length of the umbilical cord in cm at full term.

21 inches

Length of the umbilical cord in inches at full term.

2 cm

Width of umbilical cord in cm at full term.

¾ inches

Width of umbilical cord in inches at full term.

Wharton’s Jelly

The gelatinous substance that surrounds the umbilical cord to prevent cord compression.

350 mL/min

The amount of blood flow of the umbilical cord at full term.

Smooth Muscle

Type of muscle inside the walls of the umbilical cord’s blood vessel.

Nuchal Cord Condition

Happens when the umbilical cord wraps around a baby's neck in the womb.

Placenta

A flat disk-shaped structure attached in the uterus anteriorly or posteriorly near the fundus, functions as a transport mechanism between the mother and fetus.

15 - 20 cm

Diameter of placenta in cm.

2 - 3 cm

Width of placenta in cm.

Cotyledons

A fetal structure that a lobule or section of the placenta that acts as a functional unit of exchange.

15 - 20

Number of compartments in a placenta.

400 - 600 g

Weight of placenta in grams.

1 lb

Weight of placenta in lbs.

Schultze Placenta

A desciption used to describe the fetal side of the placenta; shiny.

Duncan

A desciption used to describe the maternal side of the placenta; dirty.

42 Weeks

Number of weeks in which the placenta begins to decrease in function.

12th Day

The day in which intervillous spaces of uterine endometrium begin to form.

13th Day

The day in which oxygen and other nutrients, such as glucose, amino acids, fatty acids, minerals, vitamins, and water, osmose from the maternal blood through the cell layers of the chorionic villi into the villi capillaries.

100

The number maternal uterine arteries that supply the mature placenta.

Progesterone

A hormone that maintains uterine lining for implantation of the zygote and prepares the breast for lactation; stimulates testes in men to produce testosterone.

Chorion

A thick fetal membrane that extends into the decidua basalis on the uterine wall and form the embryonic or fetal portion of the placenta.

Trophoblast

The site where the chorion membrane develops from.

Chorionic Villi

The finger-like projections of the chorion.

Amnion

A thin fetal membrane that envelops and protects the embryo and holds the amniotic fluid.

Yolk Sac

A fetal structure that begins the embyronic life and initiates the production of RBC

9th Day

The day in which the yolk sac forms after fertilization in the blastocyst.

6 Weeks

The duration in weeks the yolk sac continues to function before the embryo liver takes over.

• Endoderm

• Mesoderm

• Ectoderm

(3) Germ Layers

3rd Month Until Birth

The duration in which the placenta functions as a transport mechanism for the mother and fetus.