The Developing Baby. Conception Ovulation - About every 28 days, an ovum (egg cell) is released by one of a woman’s two ovaries. Menstruation Cycle When.

Chapter 4 Section 1The Developing Baby

ConceptionOvulation - About every 28 days, an ovum

(egg cell) is released by one of a woman’s two ovaries.Menstruation Cycle

When ovum is released from ovary, it moves through the fallopian tube into the uterus. Takes about 2-3 days

When it reaches the uterus, it usually breaks up and leaves the body with the menstrual flow.

When a sperm reaches the fallopian tube, it may penetrate and fertilize the ovum.

ConceptionConception – the sperm fertilizing the ovumThe ovum usually lives 12 to 24 hoursThe sperm can lives 48 to 72 hoursDuring a normal menstrual cycle, there are 3-

4 days in which intercourse can lead to conception.

Ectopic PregnancyOccurs when the baby begins to grow

somewhere other than in the uterus, such as the fallopian tubes.

Dangerous for the motherDo not end in a live birth

GeneticsAt the moment of conception, every human

baby receives 46 chromosomesChromosomes come in pairs you get 23 pairs

totalHalf from mother, half from father

Per pair: 1 chromosome from father’s sperm, 1 chromosomes from mother’s egg = 2 chromosomes = 1 pair

Each chromosomes has hundreds of thousands of genes

No two people, besides identical twins, have identical DNA.

Dominant and Recessive GenesFor each inherited characteristic, a person

receives two copies of a geneOne from mother, one from fatherWhen both are the same, the child gets that

gene automaticallyDominant gene – a stronger gene

Controls the characteristicRecessive gene – a weaker gene

Not expressed

Making a Unique PersonGender determined at conceptionX chromosomes = female chromosomeY chromosomes = male chromosomeEvery woman has 2 X chromosomesEvery male has 1 X and 1 Y chromosomes

At conception, the woman automatically gives X, so father determines sex (based on if he gives X or Y chromosome) XY = Male XX = Female

Multiple BirthsNumber of children determined at conception

or soon afterMost common = twins

Twins3 in 100 births are twinsIdentical

One egg and one sperm divide into two cells4 in 1,000 births are identical twins

Fraternal Two eggs released into uterus at one time, get

fertilized by two different spermMay not look alike23 in 1,000 births are fraternal twins

Three or more birthsVery rare, but more likely if using treatments

to help women get pregnant.

InfertilityInfertility – the inability to conceive a child40% linked to women40% linked to men20% unknown causes, or linked to both

partners

Options for InfertilityAdoption – A couple is legally taking on all

responsibilities and rights for raising, loving, and caring for a child in need of a permanent home.

Artificial Insemination – Doctor injects sperm into a woman’s uterus. Procedure timed to take place when a woman’s ovary releases an ovum.Sperm is often from the woman’s husbandSperm donor can be used

Options for Infertility In Vitro Fertilization – Process used to treat

many causes of infertility, such as when a woman has damaged fallopian tubes. Under microscope, the doctor combines a mature ovum from the woman with sperm from her husband and places it in the woman’s uterus. Pregnancy occurs if the fertilized egg attaches itself to the uterus

Ovum Transfer – This procedure is similar to in vitro fertilization, except an ovum has been DONATED by another woman. Then fertilized in lab, and put inside of the woman.

Options for Infertility Surrogate Mother – A woman who becomes

pregnant to have a baby for another woman. This option requires legal arrangements be made for everyone involved, including the child. THINK: Baby Mama!

All options are very expensive and often medical insurance does not cover the costs, or covers very little of the costs.

Three Stages of PregnancyGerminal Stage – fertilization of the egg

Embryonic Stage – development in 3rd – 8th week of pregnancy

Fetal Stage – From 8th/9th week until birth

Germinal StageCell Division

Zygote begins to grow by cell division while in fallopian tubes

One cell multiplies until there are hundreds of cells

Takes about 4 days to reach the opening of the uterus

ImplantationZygote attaches itself to the side of uterus and

continues to growOnly the size of a pin head

Embryonic StageAmniotic Sac forms – Liquid that forms and

protects the babyPlacenta develops – Tissue that connects the

developing baby to the uterusFormed from special layers in the uterusRich in blood vessels that allow food and oxygen

to flow to the babyUmbilical cord develops – long tube that

connects the baby to the placentaTakes carbon dioxide and other waste products

away from the baby

Fetal StageVocal Cords DevelopDigestive system and kidneys begin to

functionSpontaneous moves are possible by the end

of the third month.Development is completingFetuses are very active in the fetal stageGrows to full termReady for birth