1 / 16

Pregnancy

Pregnancy. O rgan which provides nutrients & removes waste Complete by end of 3rd month Chorionic Villi (vascular projections from Chorion ) are embedded in endometrium & allow nutrient / waste exchange, via active transport & diffusion. (16m 2 SA) Attached to foetus via umbilical cord

havard
Download Presentation

Pregnancy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Pregnancy

  2. Organ which provides nutrients & removes waste • Complete by end of 3rd month • Chorionic Villi (vascular projections from Chorion) are embedded in endometrium & allow nutrient / waste exchange, via active transport & diffusion. (16m2 SA) • Attached to foetus via umbilical cord • Umbilical veins, umbilical arteries (foetus) • Uterine veins, uterine arteries (mother) Placenta

  3. Immediately after fertilisation zygote divides (cleavage) • Journey between uterine tube  uterus (approx. 3-4 days) • Cells divide but no new cytoplasm • 36 hrs. 1st cleavage is complete • 48 hrs. 2nd cleavage complete • 72 hrs. 4th cleavage complete • Cleavage continues forming a ‘blastocyst’ (approx. 5 days after fertilisation) • Thin layer of cells surrounding a fluid filled cavity with one specific area of greater cell density (inner cell mass) Early Embryonic Period

  4. Acquires nutrients from uterine fluid • Approx. 7-8 days after fertilisation blastocyst (0.25mm diameter) sinks into endometrium (due to an enzyme) and becomes firmly attached (implantation) • Inner cell mass faces towards endometrium, blastocyst is completely covered. • Nutrients from endometrium • Increased oestrogen / progesterone from Corpus Luteum maintain endometrium & inhibit pituitary hormones Early Embryonic Period cont.

  5. Chorion secretes HCG, maintains Corpus Luteum • Secretion starts at 2nd week preg 3rd month. • Then placenta secretes oestrogen / progesterone & doesn’t need Corpus Luteum. Early Embryonic Period cont.

  6. Early Embryonic Period cont. • first two months of pregnancy: embryo • Primary Germ layers: • after implantation, inner cell mass breaks up into 3 layers (Primary Germ Layers) • 1. Ectoderm: (closer to body stalk) • epidermis (top layer) of the skin, hair, nails, glands of skin, lens in the eye, receptor cells, epithelium in mouth, nose and anal canal, teeth enamel, nervous system, A. lobe of Pituitary gland, Adrenal medulla.

  7. Primary Germ layers: • 2. Mesoderm: (middle) • Skeletal, smooth & cardiac muscles, connective tissues, lymphoid tissues, epithelium (top layers) of body / joint cavities, kidney, ureter, gonads, reproductive tracts, adrenal cortex & dermis of skin • 3. Endoderm (furthest from body stalk) • Epithelium of A.C., bladder, urethra, gallbladder, pharynx, larynx, trachea, lungs, tonsils, thyroid, thymus glands, vagina. Early Embryonic Period cont.

  8. Embryonic Membranes • Lie outside the embryo: protect and nourish • Amnion: • Encases embryo, filled with amniotic fluid • By 8th day surrounds embryo • Protection (shock absorber) • Constant body temp • Freedom of growth / movement • YolkSac: • First site of red blood cell formation • placenta. EARLY Embryonic Period cont.

  9. Embryonic Membranes • Allantois: joins with yolk sac to become umbilical cord • Chorion: outer cells of blastocyst with layer of mesodermal cells • As amnion enlarges it fuses with Chorion. Chorion eventually becomes foetal placenta. EARLY Embryonic Period cont.

  10. 4 weeks: • 4mm • Development of muscle segments on either side of the ‘spine’ tube • Tail evident, brain & liver begins to form, heart forms and begins to beat. • 5 weeks • Arm / leg buds appear • 8 weeks • 3cm, 1g • Enlarged head with eye slits & jaw, nose & ear lobes • Hands with fingers, feet with toes • External sexual organs evident Embryonic Period

  11. 12 weeks • 6cm • Body straightens, upright posture • Finger toe nails appear & hair appears • Bone marrow with red blood cells formed • 16 weeks • 18 cm, 100g • Fingerprints • Movement of foetus • Heartbeats @ 120 – 160 / min (mum: 60 – 80 / min) • Skeleton complete • 20 week • 25 cm, 300g • Body covered with fine hair • Gripping reflexes FOETAL Period

  12. 24 weeks • 27 -35 cm, 565 – 680 g • Respiratory movements • Digestive glands functioning • Eyebrows / eye lashes • 28 weeks • 38 cm, 1kg+ • Brain much larger with convolutions • In males testes descend into scrotum • All systems functioning minus respiratory • 32 weeks • 41 – 45cm, 2.2 kg • Fat beneath skin • 36 – 40 weeks • 50 cm, 3.3 kg • Boys approx 100g heavier • Eyes open • Well formed nose • Fine body hair is shed FOETAL Period

  13. Signs of Pregnancy • Failure to menstruate • Fuller, firmer, more tender breasts • Larger, darker nipples • Morning sickness (nausea / vomiting) • Increased urination frequency (pressure form uterus) • Enlargement of abdomen. • Changes to Mother during pregnancy • no great change to a woman during embryonic period • during lat foetal period, foetus has high demands • mother functions slow down  nutrients stay in blood longer • Constipation • mothers blood vol increases (40%) & faster circulation (increased heart rate and vol) • Increased urine production Pregnant Mother

  14. May be fixed by microsurgery, surrogacy, AID or ART • Artificial Insemination by Donor (AID) • 70% - 80% effective • Male is sterile therefore semen is donated by an unknown man (generally physically similar). • All donors are screened for STI’s and genetic diseases, mental problems and general health. • Semen is injected into woman’s upper vagina around expected time of ovulation for 3-4 consecutive days. (generally for 3 months) • Surrogacy • Woman agrees to bear a child for a couple. (fertilised either naturally or artificially with male semen and surrogate egg OR using ART) Treatment of infertility

  15. Assisted Reproductive Technologies (ART) • In vitro Fertilisation (IVF) • takes ovum from mother, fertilise outside body, then transplant embryo to uterus • Gamete Intrafallopian transfer (GIFT) • variation of IVF • Eggs and sperm immediately mixed together, then mixture immediately injected in to fallopian (uterine) tube. • Most require women to take fertility drugs which increase number of eggs released by ovaries. • Often more embryos are created than are needed so the excess are frozen. (may be used if initial is unsuccessful, donated to another couple, discarded or used for research) Treatment of infertility

  16. Assisted Reproductive Technologies (ART) cont. • Intracytoplasmic Sperm Injection (ICSI) • 20-30% effective • Single sperm injected into a single egg and embryo transplanted into females uterus. • May increase likeliness of birth defects. • Donor Egg or Embryo • Donated egg is mixed with parents sperm and resulting embryo implanted into females Uterus. • Could also be donated embryo. Treatment of infertility

More Related