Human Growth and Development - Fetal Period and Placenta

A set of vocabulary flashcards covering human growth and development, gestational milestones, growth restriction categories, and placental components.

Fetal Period

The stage of development from the 9th week to birth, characterized by maturation of tissues and organs and rapid body growth.

Crown-Rump Length

The measurement used to determine fetal sitting height.

Crown-Heel Length

The measurement used to determine fetal standing height.

Length of Pregnancy (LNMP)

280 days or 40 weeks after the last normal menstrual period.

Length of Pregnancy (Fertilization)

266 days or 38 weeks after fertilization.

3rd Month Milestones

Developmental stage where the face becomes more human looking, eyes move ventrally, ears move laterally, limbs reach relative length, and primary ossification centers are formed.

Lanugo Hairs

Fine hair appearing on the fetus during the 4th month of development.

Quickening

The initial perception of fetal movements by the mother, occurring in the 5th month.

Vernix Caseosa

A whitish, fatty substance secreted from sebaceous glands covering the fetal skin.

Intrauterine Growth Restriction (IUGR)

A condition where a fetus does not achieve expected in utero growth potential due to genetic or environmental factors, defined as an estimated fetal weight below the 10th percentile.

Moderate FGR

Fetal growth restriction defined as a birth weight in the 3rd to 10th percentile.

Severe FGR

Fetal growth restriction defined as a birth weight less than the 3rd percentile.

Small for Gestational Age (SGA)

Infants born with a birth weight below the 10th percentile for gestational age.

Placenta

An organ that facilitates nutrient and gas exchange between the maternal and fetal compartments.

Chorion Frondosum

The structure that forms the fetal component of the placenta, derived from the trophoblast and extraembryonic mesoderm.

Decidua Basalis

The structure that forms the maternal component of the placenta, derived from the uterine endometrium.

Placental Functions

1. Exchange of gases, 2. Exchange of nutrients and electrolytes, and 3. Transmission of maternal antibodies.