Aim: How does an embryo develop inside the uterus?

How long are humans pregnant? Females are pregnant for nine months or 38 weeks During this time, the mother and baby undergo many changes. _id=9http:// _id=9 check out this webpage for videos of development

Embryo vs. Fetus Embryo Fetus (Fertilization-9 weeks) (9 weeks-Birth) Once the embryo becomes a fetus, all the major organs have begun to form.

In the uterus - womb Surrounded by an amniotic sac & fluid for protection from shock Where does the embryo develop?

Why is the fetus floating in a fluid? The fetus is surrounded by amniotic fluid and it helps absorb shock

What does a developing embryo need? 1. Nutrients for ATP & to build its own body parts 2. Oxygen for ATP

Placenta The placenta is the organ that allows for the exchange of nutrients and wastes

Embryonic Waste Products 2. Carbon Dioxide 1. Metabolic waste (from cells)

Umbilical Cord The umbilical cord is responsible for carrying nutrients and oxygen to the developing fetus, and waste away.

Fetal Blood Supply The blood from the mom and the embryo NEVER mix. Materials diffuse between the mother’s blood & the baby’s blood.

What happens at around 9 months? The fetus has developed all its organs and is ready to live in the outside world The uterine muscles begin to contract and the baby is forced out of the mother. This process is called:Labor

Prenatal care Good nutrition Moderate exercise No smoking No drugs, prescription or illegal No alcohol

Don’t get morning sickness: Thalidomide (1950)

Fetal Alcohol Syndrome (FAS) Consuming alcohol during development can cause FAS which has disastrous affects on the CNS. Includes: Low birth weight (poor growth) Small cranium Organ dysfunction Failure to thrive Developmental delays, learning dis. Facial abnormalities (small eyelid,nose Mental retardation

What trimester is the most dangerous? The first trimester, because all the organs are forming at this time. Dangerous chemicals can affect cell division.

STRUCTURES BY 3rd WEEK hp?mov_id=9http:// hp?mov_id=9 Placenta Nervous and endocrine system (starting) Vital organs forming Heart is beating

FIRST TRIMESTER (3months) Most major organs formed Umbilical cord formed Muscular system developed Reflexes Amnion formed

SECOND TRIMESTER Tissues become specialized Skeleton forms Strong fetal heartbeat At ~6 months the baby can live outside the mom with life support

3rd Trimester Fetus doubles in size Lungs are forming Sleeps 90-95% of the time Dreams Premature if born before 8 months

5 wks; 10 mm