Chapter 19 Lesson One Pgs The Beginning of the Life Cycle

Male Reproductive System

Female Reproductive System

Ovulation

Fertilization The union of a male sperm cell and female egg cell is called fertilization or conception

Implantation The zygote has divided many times to form a cluster of cells The zygote (fertilized egg) travels through the fallopian tube The zygote attaches to the uterine wall (implantation)

Embryo: the cluster of cells that develop between 3-8 weeks of pregnancy

Fetus: development of the unborn baby after eight weeks

Stages of Fetal Development First Trimester (0-14 weeks) Spinal cord grows Brain, ears, and arms begin forming Heart begins to beat 12 week fetus

Stages of Fetal Development Second Trimester (15-28 weeks) Fetus body grows Mother can feel fetal movement Eyebrows and eyelashes develop Fetus can hear 20 week fetus

Stages of Fetal Development Third Trimester (29-40 weeks) Fetus uses all five senses Fetus gains weight Fetus becoming crowded in uterus Lungs fully develop 36 week fetus

Stages of Birth In final weeks, mother experiences weak contractions Contractions become regular and stronger The cervix dilates, preparing for the baby to exit Labor is the final stage, the uterus contracts and pushes the baby out

Life Outside the Womb Begins!