1. C HILD C ARE & D EVELOPMENT Chapter 4 Pregnancy

2. C ONCEPTION Cell – the smallest unit of life; able to reproduce itself Germ cells – the cells involved in reproduction; one from the male, one from the female What are the male and female germ cells called?

3. C ONCEPTION Sperm – male germ cell Ovum – female germ cell Conception – the joining of the sperm and ovum

4. C ONCEPTION Zygote – the single cell that results from the joining of the sperm and ovum, otherwise known as the fertilized egg Sex chromosomes – make up the 23 rd pair; sex determined by this pair; XX = female, XY = male

5. M ULTIPLE P REGNANCY Multiple pregnancy – two or more babies develop in the same pregnancy Frequency of twins in U.S. is 1 in 35 births Likelihood have having three or more babies is 1 in 540 births Becoming more common due to women using fertility drugs as well as older women having children Many babies in multiple births are born early and have lower birthweights

6. T WINS Fraternal twins – when multiple babies develop from two or more ova fertilized by different sperm, each child has a different genetic make- up; the most common type of multiple Identical twins – when multiple babies develop from a single ovum, fertilized by a single sperm, that splits; babies may have the same genetic make-up or be very similar in appearance

7. T WINS

8. P RODUCTION OF TRIPLETS See page 119 in book One egg set = all identical Two egg set = two identical, one fraternal Three egg set = all fraternal

9. S TAGES IN DEVELOPMENT Prenatal development – takes place from conception to birth; divided into three stages Germinal stage – from conception to two weeks; baby called a zygote Embryonic stage – two weeks to eight weeks; baby called an embryo Fetal stage – 9 weeks to birth; baby called a fetus

10. S TAGES IN DEVELOPMENT Germinal stage – from conception to two weeks; baby called a zygote Cell division occurs Fertilized egg embeds in wall of uterus Amniotic sac, placenta, and umbilical cord form

11. S TAGES IN DEVELOPMENT Embryonic stage – two weeks to eight weeks; baby called an embryo Heart, liver, lungs, digestive system, and brain develop Tissue segments in spinal column form Limb buds appear Ears and eyes begin to form

12. S TAGES IN DEVELOPMENT Fetal stage – 9 weeks to birth; baby called a fetus 9 weeks Facial features form Limbs, hands, feet, fingers, and toes develop 12 weeks Muscles form Teeth and vocal cords develop Eyelids and nails appear 16 weeks Lanugo (hairlike growth) appear Heartbeat audible by stethoscope Eyebrows and eyelashes grow

13. S TAGES IN DEVELOPMENT Fetal stage – 9 weeks to birth; baby called a fetus 20 weeks Sweat glands form Head hair appears Vernix caseosa (waxlike substance) covers body Skin develops 24 weeks Eyes mature Taste buds develop 28-40 weeks (Rapid growth) Lanugo (hairlike growth) disappears Fatty tissue forms under skin Body organs mature

14. S TAGES IN DEVELOPMENT Amniotic sac – surrounds the cells to protect the baby until birth Placenta – an organ filled with blood vessels that develops against the wall of the uterus; the umbilical cord grows out from the placenta Umbilical cord – contains three blood vessels that connect the child with the placenta; nourishes the baby, removes wastes

15. S TAGES IN DEVELOPMENT Quickening – movements felt by the mother around four and five months; the baby is turning, moving its head, pushing with its hands and feet Linea Nigra – dark vertical line running along belly button due to the increase of the pigment melanin (from increase of estrogen); happens in ¾ of all pregnancies