Embryonic development and Pregnancy Another term for pregnancy is the gestation period It lasts for about 280 days which is slightly more than 9 months

Embryonic development and Pregnancy Embryo increases in shape and size as it grows By 12 weeks the embryo has grown quite a lot, and will look clearly like a human baby It is now called the foetus

Development of the extra-embryonic membranes Soon after the blastocyst itself to the uterus wall, 2 membranes develop around it Extra-embryonic membranes

Development of the extra-embryonic membranes These membranes are: The chronian on the outside, forms chronic villi An amnion, on the inside, with amniotic cavity filled with amniotic fluid

Development of the extra- embryonic membranes Chronic villi with uterine tissue make up the placenta A hollow rope-like tube called umbilical cord, attaches the embryo to the placenta

Development of the extra- embryonic membranes The placenta has the following functions: Attachment of embryo to mother Diffusion of desolved food from mother to foetus

Development of the extra- embryonic membranes Diffusion of oxygen from mother to foetus and carbon dioxide from foetus to mother

Development of the extra- embryonic membranes After 12 weeks of pregnancy it secretes its own progesterone which maintains pregnany

Development of the extra- embryonic membranes The amniotic fluid has the following functions: Shock absorber Prevents dehydration

Development of the extra- embryonic membranes Keeps foetus within a small temperature range Allows free foetal movement for growth and development

Development of the extra- embryonic membranes The umbilical cord contains the umbilical artery and vein The artery carries deoxygenated blood with nitrogenous wastes from the embryo to the placenta The vein carries oxygenated blood and food

Birth Occurs about 280 days after fertilisation, this happens in 3 stages Stage 1: Uterus contracts Head pushed against cervix Membranes break Cervix dilates

Birth Stage 2: Baby forced out through birth canal Umbilical cord cut Baby handed to mother Stage3: Placenta becomes loose Placenta pushed out as the ”after-birth

Contraception MethodDescription Natural Methods WithdrawalThe penis is removed out of the vagina before ejaculation but it is not safe method because many sperms are released during sexual intercourse Rhythm method Sexual intercourse is avoided during ovulation. This is not a safe method of contraception because it is impossible to be 100 % sure when ovulation will occur

Contraception MethodDescription Barrier methods CondomAct as a barrier to stop sperms from entering the vagina FemidomAct as a barrier to stop sperms from getting into the uterus/Fallopian tubes IUD/loopIt prevents fertilised eggs/embryos from becoming attached to the uterine wall and is highly effective DiaphragmIt covers the cervical opening and prevents sperm from entering the uterus and is fairly effective

Contraception MethodDescription Chemical /drug treatment SpermicidesIt contains a chemical substance that kills sperm and acts as a barrier/prevents sperm from entering the Fallopian tubes. They are not very reliable on their own. Contraceptive pills Contains artificially produced hormones which prevents the production of eggs/ovulation. Signalling the body that it is already pregnant. It changes the lining of the cervix/womb. It is a very reliable method. Contraceptive injections It contains progesterone/combination of oestrogen and progesterone which stops ovulation/changes the lining of the womv and the cervix. It works for 2 to 3 months and are very effective.

Contraception MethodDescription Surgical methods Male Sterilisation The sperm ducts are cut and tied. Semen without sperm is produced and is a very effective method of contraception. Female Sterilisation The Fallopian tubes are cut and tied during a small surgical operation preventing the fusion of sperm and egg

syphilis Caused by spiral bacterium, treponema pallidum Transmission: Sex with infected partner, mother to child Symptoms: Nodules on sex organs Rash over the body Sore throat and aching muscles

syphilis Can attack tissue or organ including skin Lead to blindness and death Treatment: Antibiotics in early stages

gonorrhoea Causes: Coccus bacterium, gonococus Transmission: Sex with infected person Symptoms: Frequent and painful urination, discharge Sterility in men and woman

gonorrhoea Treatment: Antibiotics, penicillin More difficult to cure in late stages

Prevention of stds Most stds are life-threatening For many of them, there is no cure Medication, nutritious diet and healthy lifestyle can slow down progress of the disease Use A B C method Abstain from sexual activites Be faithful to your partner Condomise