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Pregnancy

Pregnancy. Development of fetus. After 3 weeks the fertilised egg is dividing rapidly . It has formed a ball of cells which is too small to be seen without a microscope .

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Pregnancy

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  1. Pregnancy

  2. Development of fetus • After3 weeksthefertilisedeggisdividingrapidly. It has formed a ball of cellswhichistoosmallto be seenwithout a microscope. • After 6 weekstheball of cells looks like a tadpole. There’s a ‘head end’ and a ‘tale end’ and a bulge, wheretheheartisforming. • After8 weeksyou can seetheeyes. Arms and legshaveformedwithtinyfingers and toes. Itisnowcalled a fetus. • After12 weeksthefetusisabout 50mm long. It can kickitslegs and moveitsfingers. Its head isout of proportionwiththerest of thebody. Most of theorgansinsideitsbody are working. • After24 weeksthefetus has grown so muchyou can seethemotherispregnant. She can feelthebabymovinginisdeher and hisheart can be heardbeating. • After30 weeksthebabyisalmostreadyto be born. It’s head isjustabovethecervix. Pregnantwomanmust: • Eat a balanceddiet, toprovidethefetuswithnutrients • Increaseintakeof iron (haemoglobin), calcium (fetus’ teethand bones) and folicacid (nerves) • Drinkwatertokeepherself and thefetushydrated Pregnantwomenshouldnot: • Smoke- carbonmonoxide reduces theamount of oxygenthatreachesthefetus. Thismeanslowbirthweight and maybeprematurebirth. • Drink alcohol- toxic, causes addiction. • Takedrugs- toxic and causes addiction. • Exceesive sport- could cause damagetofetus as itmoves a lot.

  3. Thefunctions of the placenta The placenta isthelungs and thekidneys of thefetus: • Itgivesthefetusoxygen and takesawaythecarbondioxide (lungs) bydiffusion • Itgivesthefetusnutrientse.g. Glucose (to respire forenergy), amino acids (celldivision- growth), vitamins ( D and C), minerals ( calciumforbones and teeth, and ironforhaemoglobintocarryoxygen), and water. • Ittakesaway urea and toxins (kidneys) • Itgivesantibodiesforthefetus’ immunitytoinfectionswhenborn Alcohol, drugs and viruses can crossthe placenta. The umbilical cord • Thefetusisattachedtothe placenta bythe umbilical cord. It has 2 arteries and 1 vein: • Umbilical arteriescarrybloodfrom: embryo placenta(mother) (deoxygenated) CO2 + Urea • Umbilical veinscarrybloodfrom: placenta (mother) embryo (oxygenatded) 02, glucose, amino acids, vitamins, minerals, H20 Themothersbloodnever mixes withthe fetal blood- theymayhave differentbloodgroups and themother’sbloodis at a higherblood pressure.

  4. Theamnioticsac • Itgrowsfromthedevelopingembro. • It’sfunctionisto secrete theamniotic fluid. • Thisrippsjustbeforebirth. Theamniotic fluid • Theembryois suspended in this fluid. • Theamniotic fluid protectsthefetusagainstmechanical shock- the fluid acts as a shock absorber • Itpreventsthefetusfromdryingout (hydratesthe fetal cells) • Itregulatestemperature and preventsfluctuations Amniocentesis is a test tocheckforabmormalities of thefetus. A sample of amniotic fluid iscollectedwith a syringe. The test givesinformationaboutchromosomemutation (Down’ssyndrome) and gene mutation (Cystic fibrosis). Theprocedureisoftenofferedtoolderwomen as abnormalities are more common in oldermothers. Itisusuallycarriedout at 16-18 weeks.

  5. Birth

  6. Processesinvolved in labour and birth A babyisbornafter 36 weeks. Usuallyitislying head downwardssincethe position makesiteasierforbirth. Thestart of birthiswhenthemotherfeelsthemuscles of heruterusstarttosqueeze. These ‘sqeezes’ are calledcontractions and at firsthappenevery 30 minutes. Themotherisnow in labour. Thebabyissurroundedbytheamnioticsaccontaining fluid. As theuterusslowlypushesthebabyout, thesacbusrtslettingouttheamniotic fluid (watrsbreaking). Contractionsnowbecomestonger and come every 3 minutes.Whenthebabyisbornitisstillattachedtothe placenta bythe umbilical cordwhichmust be cut and tied. Latertherest of thecord and placenta come out and thisiscalledtheafter-birth.

  7. SexuallyTransmittedDiseases

  8. HIV- Human Immunodeficiency Virus How do youcontact /pick up HIV? 1) Unprotected sexual intercoarsewithaninfectedperson 2)Mothertofetusvia placenta and breastmilk 3) Sharingsyringesbetweenheroinaddicts 4) Bloodcontactvia open wounds How do youpreventthe spread of HIV? 1) Educatepeopleaboutsafe sex 2) Give free condomstoprostitutes 3) Test todetect HIV positive individuals 5) Povide free anti-retroviral drugstodevelopingcountries (anti-retroviral drugsinhibittheenzymesthe virus uses tomultiplyinsidethe T-lymphocytes) Howdoes HIV affectthebody? HIV attacks and invades T lymphocytes (These are WBC’swhichprotectyoufromviruses) At firstyouget ‘flu-like’ symptoms. E.g. Fever, muscleaches, head-ache, chills After a fewweeksyoufeelhealthybutyou are HIV positive and you can spread the virus touninfectedpeople. HIV uses it’s RNA and enzymestotakeoverthe T lymphocytes and form new viruses Thenumber of T lymphocyteswilldecrease and aftersomeyearsyoudevelop AIDS. AIDS istheresult of a veryweakimmunesystem as there are notenoughWBC’stopreventthepersonfromgettinginfectections. They pick up diseaseslikepneumonia, tuberculosis and cancer. Peoplewith AIDS onlylivefor 1 or 2 years

  9. Gonorrhea Gonorrheaistransmittedbyhaving : • Oral sex • Unprotectedvaginal or anal sex as the bacteria live n the semen and/or vaginal fluids Symptoms of disease: Treatment: antibioticse.gpenicillin Long-termeffects: infertility, urethradamaged Prevention: Use a condom

  10. Comparison Similarities They are bothtransmittedbyunprotected sexual intercourse. Theyboth travel in bodyfluids and only a condompreventstheirtransmission.

  11. Lactation

  12. Tobreastfeedornot? • Happens in allmammals. A hormone (oxytocin) isreleasedwhich causes themammarygland in thebreatsto produce milk. Thebaby’ssuckingstimulatestheglandsto produce more milk.

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