The first cell of a new human being

Forms following fertilization, joining of a sperm and egg

Processes of Development

(following fertilization)

Cleavage

Growth

Morphogenesis

Differentiation

To cleave

Occurs after fertilization

Cell division with no increase in size

Cells take on different structures and functions

Outside the embryo

Chorion

Yolk Sac

Allantois

Amnion

Develops into the fetal half of the placenta

Organ that provides the fetus with nourishment and oxygen and takes away it's waste

Fully functional by the end of embryonic period (2 months)

First site of blood cell formation

Blood vessels that become the umbilical blood vessels

Contains fluid to cushion and protect the embryo

Early stage in development in which embryo consists of a mass of cells

Refers to the time from fertilization to birth

Lasts about 280 days from the last menstruation

Human Chorionic Gonadotropin

Secreted by the trophoblast

Is the hormone that is the basis for the pregnancy test

An example of morphogenesis

Cells move/migrate to become primary germ layers

Tissue layers of the embryo

Ecotoderm-(outer layer) skin, nervous system

Mesoderm-(middle layer) all body systems

Endoderm-(inner layer) epithelial lining

The nervous system

*brain

At the moment of fertilization

Males XY

females XX

Parturition

(3stages)

Birth

Stage1-oxytocin starts uterine contractions, ends when cervix has dialated completely

Stage2-contractions 1-2 min apart, baby's head descends into vagina, birth occurs

Stage3-placenta expelled from vagina

Hormone released by pituitary that causes contraction of uterus and milk letdown

"cuddle hormone"

The fetal lifeline

Transports fetal blood to and from the placenta

transports waste to placent and oxygen and nutrients to fetus