FOETAL DEVELOPMENT AND MATERNAL BEHAVIOUR MARCH 25 2013

FOETAL DEVELOPMENT AND MATERNAL BEHAVIOUR MARCH 25, 2013 CAPE BIOLOGY MRS. S. HAUGHTON

UPTAKE ACROSS PLACENTA • Chorionic villi have microvilli which increase surface are for absorption • Osmosis, diffusion, facilitated diffusion, active transport and pinocytosis assist in transporting substances across the placenta • Many mitochondria in the cells making up the chorionic villi. Why do you think this is so?

FOETAL DEVELOPMENT AND MORTALITY

EXCHANGE OF SUBSTANCES ACROSS PLACENTA

USEFUL SUBSTANCES • Water: osmosis • Nutrients: glucose (facilitated diffusion), amino acids, lipids, mineral salts and vitamins (active transport) • Respiratory gases: oxygen diffuses from maternal blood to foetus; foetal haemoglobin has a higher affinity for oxygen so readily absorbs this from mother across placenta. Carbon dioxide diffuses from foetus to mother.

USEFUL SUBSTANCES • Excretory products: nitrogenous waste produced by the foetus (mainly urea) diffuses from foetus to mother across placenta to be removed by mother’s kidneys. • Antibodies: to protect foetus from diseases to which the mother is immune (has antibodies) • Endocrine organ: from 3 rd month, placenta is the main source of oestrogen and progesterone. It also secretes human chorionic gonadotrophin (HCG) and human placental lactogen (HPL).

HARMFUL SUBSTANCES • Cigarette smoke: tars, irritants, carbon monoxide and nicotine; CO and nicotine enter mother’s blood and may cross the placenta into the baby’s circulation; smoking 30 cigs a day decrease birth weight by 10%; blood vessels in umbilical cord are narrower in smoking mothers; premature birth, late miscarriage, reduced intelligence.

EFFECTS OF ALCOHOL • Crosses placenta easily • High level of drinking leads to FAD (foetal alcohol syndrome) • Mental retardation • Microcephaly (small head/brain) • Behavioural problems • Reduced growth rate • Poor muscle tone • Flat face (poorly developed cheek bones), long thin upper lip, short upturned nose, cleft palate

EFFECTS OF DRUGS • Most sensitive to drugs during organ development (3 rd week of pregnancy); heroin and cocaine causes foetal addiction • Pharmaceutical drugs are carefully tested and should be considered safe unless otherwise stated on the label; thalidomide for morning sickness in the 1960 s increased need for more testing of drugs

THALIDOMIDE BABIES

EFFECTS OF VIRUSES • Most bacteria too large to pass through • Most viruses small enough to pass through the placenta • Rubella causes miscarriage or deformities • HIV and hapatitis B are life threatening

EFFECTS OF RHESUS FACTOR • Antigen found on the cell surface membranes of red blood cells • 84% persons are Rhesus positive; the others are Rhesus negative

STAGES OF BIRTH • Uterus becomes sensitive to oxytocin released from the pituitary glands • Causes contraction of smooth muscles of myometrium of uterus • The hypothalamus of foetus secretes hormones which causes mother’s progesterone levels decrease; this stimulates oxytocin levels top increase

STAGES OF BIRTH

LACTATION

COLOSTRUM • The first secretions of the breasts, following birth, is not milk but colostrum. • This has a yellow colour and is rich in globulin (protein) but low in fat. • It romotes passing antibodies from mother to baby.

CHANGES IN FOETAL CIRCULATION AFTER BIRTH • Page 747 -748

PREGNANCY DO’S

1. You Should Get Regular Medical Exams 2. You Should Get the RDA (Reccomended Daily Allowance) for Folic Acid 3. You Should Check Your Immunity to German Measles (Rubella) 4. You Should Take Prenatal Vitamins 5. You Should Eat Plenty of Protein 6. You Should Eat Well and Get Plenty of Exercise. 7. You Should Be Sure to Get Enough Fat in Your Diet 8. You Should Do Kegal Exercises 9. You Should Focus on Your Child and Avoid Negative Thoughts and Actions 10. You Should Take Care When Traveling 11. You Should Talk to Your Doctor about Existing Conditions and Your Family History

PREGNANCY DON’TS

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. You Should Not Smoke or be Around People Who Do You Should Not Drink Alcohol You Should Not Take Illegal Drugs You Should Not Take Presecription Drugs or Over the Counter (OTC) drugs, Including Aspirin, Unless Told to Do So by Your Doctor You Should Avoid Hot Dogs You Should Avoid Caffeine You Should Avoid Contact with Reptiles You Should Avoid Tick Bites You Should Avoid Fish You Should Not Eat Junk Food You Should Avoid Vitamin A Supplements You Should Avoid X-Rays You Should Avoid Microwaves You Should Avoid Stress You Should Not Expose Yourself to Pesticides You Should Avoid Fumes from Paint, Paint Thinner, Household Cleaning Products and so on You Should Avoid Raising Your Body Temperature You Should Avoid Cleaning Cat Litter Boxes. You Should Avoid Uncooked Meat. You Should Avoid Herpes