FETUS

PLACENTA

UMBILICAL CORD

CERVIX

AMNION

Functions of the PlacentaFunctions of the Placenta

Slide 16.55

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Forms a barrier between mother and embryo (blood is not exchanged)

Delivers nutrients and oxygen

Removes waste from embryonic blood

Becomes an endocrine organ (produces hormones) and takes over for the corpus luteum Estrogen

Progesterone

Other hormones that maintain pregnancy

FETUS PLACENTA UMBILICAL CORDCERVIX AMNION

mother embryonutrients oxygen

Carbon dioxide wastesmother

embryo placentaembryo

mother placentaplacentaplacenta

1.During the human development, membranes _________________ and nourish the embryo.protect2.The amnion is a membrane that ______________ and protects the developing embryo within the uterus.nourish

Factors that can affect fetal development How each factor affects fetal development

Radiation – X rays

Infectious microorganisms – virus & bacteria

Drugs – Heroin, LSD, cocaine, alcohol

Smoking

Malnutrition

MutationsFetus organs may do not work

Permanent brain damage, blindness, or death

Baby’s addiction to drugsMental retardation

Premature birthLower birth weight

Lower birth weigh

Test & Exams

• Friday 6th June: Test Human Reproduction

• Friday 13th June: Final Exam

• Monday 16th June: Final Exam

1) Do the data in the given tables justify scientists' conclusions that alcohol causes physical abnormalities at birth by interfering with the normal development of the fetus? Using one or more complete sentences, defend your position with supporting data.

Yes. The babies whose mothers drank alcohol were smaller (2,555 g and 46.8 cm) than the babies whose mothers did not drink alcohol (3,094 g and 50.1 cm).

2) What additional data would be needed to better support the scientists' conclusions?

3) Using one or more complete sentences, explain why alcohol consumption by the mother is especially harmful during the early stages of pregnancy

Alcohol is considered a poison, and it could interfere with cell division as the fetus is developing.

Scientists could get I.Q.'s of the children when they get older to determine if they have intellectual problems.

4. Identify the structure labeled A and explain how the functioning of structure A is essential for the normal development of the fetus. [2]

5. Explain why consumption of alcoholic beverages by a pregnant woman is likely to be more harmful to her fetus than to herself. [1]

Structure A:

Women are advised to avoid consuming alcoholic beverages during pregnancy.

•When the alcohol from the mother’s bloodstream enters the fetus, the relative amount is much greater due to the smaller size of the fetus.•The fetus is still developing.

Structure A is Placenta

Nutrient and oxygen in the blood of the mother diffuse into the blood of the embryo through placenta. Wastes and carbon dioxide diffuse from the blood of the embryo into the blood of the mother through placenta