1. Ch. 4.1 Notes: The Developing Baby

2. menstrual cycle called ovulation
I. Conception: the process by which a sperm cell reaches the Fallopian tube and penetrates and fertilizes an ovum this results in the beginning of a pregnancy
every 28 days and ovum (egg cell) is released by one of the woman’s 2 ovaries
menstrual cycle called ovulation
women's body release specific hormones that prepare uterus for egg fertilization
Uterus: organ in a woman’s body in which a baby develops during pregnancy (pear shaped muscle/expands)
During ovulation inner lining grows and thickens: if the ovum is not fertilized the lining breaks down bleeding during menstrual period

3. I. Conception Continued
Ovum released from ovary 2-3 days to travel through fallopian tube (connects ovary to the uterus)
Ovum reaches the uterus it disintegrates and leaves the body with menstruation
Sperm: male cell
Reaches the Fallopian tube may penetrate and fertilize the ovum  conception
Ovum lives hrs.; sperm is capable of fertilizing an ovum approximately hrs.
During the menstrual cycle there are approximately 3-4 days in which intercourse can lead to conception

4. 3 Stages of Prenatal Development
II. The Germinal Stage
A.) Cell division 000000 
Formation of the zygote: fertilized egg
2 weeks
4 days reaches the uterus
B.) Implantation:
Lining of uterus thickened enough for zygote to attach
Covered over by the lining
Size of the head of a pin

5. III. The Embryonic Stage
3rd-8 week of pregnancy
Embryo grows rapidly
Organs and body systems:
Cells begin to separate and develop into major systems of the human body; heart, lungs, bones and muscles
Not ready to function but continue to develop through pregnancy
27 days after conception neural tube: tube in back of developing baby that will become the brain and spinal cord has closed
Brain takes control of body systems
6wks. Connections between brain & spine allow first movements of baby
Crucial stage very sensitive to damage from drugs and alcohol
AVOID THESE SUBSTANCES DURING PREGNANCY

6. III. The Embryonic Stage
4. Amniotic Sac:
Formed from special layers of cells in the uterus
Fluid sac forms around the embryo: protects the developing baby
Embryo 1in to 2.5 cm. long
5. The Placenta and the umbilical cord
Rich in blood vessels
Attaches to the wall of the uterus
Mothers bloodstream carries food and oxygen to the placenta
Placenta’s job is to absorb oxygen and nourishment from the mother’s blood to be transmitted to the baby through the
umbilical cord: connects the baby to the placenta
: takes carbon dioxide and other waste products away
: stiff and firm; not flexible enough to loop around the fetus but does occur in rare cases

7. IV. The Fetal Stage: 8th or 9th week or pregnancy  birth
Fetus: developing baby
Bulbs of 20 baby teeth appear; vocal cords develop; digestive system and kidneys begin to function
Making movements
Fluttering like a butterfly
First movements can help doctor determine baby’s age; developing normally and accurate due date

8. IV. The Fetal Stage: 5. Completing development
Preparing the fetus to live independently
Organs become ready to function without any help
Fetus gains weight rapidly
Fat deposits (help baby maintain body heat) form under the skin
Fetus stores nutrients and builds immunity to diseases and infection

9. IV. The Fetal Stage: 6. Staying Active 7. Growing Bigger
Suck thumb, cough, sneeze, yawn, kick, hiccup, cry
Change positions
7. Growing Bigger
Fetus grows so does the amount of surrounding amniotic fluid
Uterus expandsabdomen grows
Less room to move
Curls up inside the uterus in the fetal position

10. V. Preparing for Birth
Common length of pregnancy is about 40 weeks or 280 days from first day of the last menstrual cycle
Fetus is fully developed and can survive outside of mother’s body without a great deal of medical assistance
Physical Changes for the Mother
Majority of births the fetus is upside down head nestled in mother’s pelvis
Baby less active because of little space to move
“breech presentation” can result in cesarean section