Theprocessofconceptiofffhcgjn 100822024105 Phpapp01 [Autosaved]

8/19/2019 Theprocessofconceptiofffhcgjn 100822024105 Phpapp01 [Autosaved]

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THE

PROCESSOF

CONCEPT


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OVA• Released from the Graafian

Follicle• Will be surrounded by a ring ofmucopolysaccharide fluid(Zona pellucida) and a circle ofcells (Corona radiata)

• Zona pellucida and Corona

Radiata protects the ova byserving as a buffer against injury

• Moves from the ovary to thefallopian tube through the ciliaand peristaltic movement offallopian tube


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SPERM•Per ejaculation, 2.5ml semen

containing 50-200M spermatozoais released (ave 400Msperm/ejaculation)

•Moves through the cervix, uterus,fallopian tube because of theirflagella and uterine contractions

•UndergoesCAPACITATION (changes in the plasma membraneof the sperm head to reveal sperm binding receptor sites) beforepenetrating into the corona radiata


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• Sperm clusters around coronal

cells

• Will releaseHYALURONIDASE (proteolytic enzyme) to dissolvethe corona radiata

• Sperm penetrates the cell; cell

membrane of ova changescomposition to becomeimpenetrable to other sperm


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• Sperm and ova fuse carrying 23 pairs of chromosomes e

• If sperm carries X sex chromosome paired with the ovum Xchromosome = female zygote

• If sperm carries Y sex chromosome paired with the ovum Xchromosome = male zygote


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IMPLANTATION

• Zygote move from fallopian tubeuterus

• It will undergo series of mitoticdivisions resulting to a cleavageformation, 1 in every 22 hour, withe cleavage division happening

hours after fertilization

• Once it reaches the uterus, zygotnow composed of 32 -50 ball of ctermed as a MORULA


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• Another 3-4 days, morula becomes a BLASTOCYSTconsisting of:

•An inner cell masswhich will becomethe future embryo

•Trophoblast whichwill become theplacenta andmembranes


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• At approx 8-10 days afterfertilization, blastocyst attacto the endometrium

• Sheds off last residues ofcorona radiata and zonapellucida

• Brushes againstendometrium (appositioand settles down

• A slight vaginal bleeding isexperienced duringimplantation stage becausecapillaries are ruptured by timplanting trophoblast cells


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FETAL

STRUCTURESDECIDUA – uterus that hathick and vascular3 areas

Decidua basalis – lies direthe embryo (portion wheretrophoblast establish commwith maternal blood vesse

Decidua capsularis – portistretches or encapsulates thof the trophoblast

Decidua vera – the remainof the uterine lining


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CHORION

C VILLIMiniature villi similar toprobing fingers that appearthe 11th or 12th day

They begin the formation othe placenta

Consists of a central core oconnective tissue and fetalcapillaries


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•Consists of 2 layers oftrophoblast cells:

• Sy!yt"otrophoblast (syncitial layer) – producesHCG, somatomammotropin (human placental

lactogen), estrogen and progesterone

• Cytotrophoblast (middle or Langhan’s layer) –functions in early pregnancy to protect the growingembryo and fetus from infection (eg syphilis)


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PLACEN

TA15-20cm in diameter, 2-3cm deep, 400-600g at fullterm

has 25-30 cotyledons(placental compartmentsthat lie on the maternalside)

has 2 sidesmaternal – dirty rough

fetal – shiny smooth


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FUNCTIONS:

Serves to conduct oxygen and nutrients for the fetus

Secretes endocrine hormones (syncytial cells)

hC# $ %st pla!tal hor'o

- enusures corpus luteum to continuously produceprogesterone and estrogen

- supresses maternal immunologic reaction so thatplacental tissue is not detected and rejected as a foreignsubstance


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- if fetus is male, stimulates the testes to beginproducing testoterone

- at 8 week, begins progesterone production, as a resCL disintegrates and hCG production decreases

ESTROGEN (estriol) – “hormone of women”

- contributes to mammary gland development of moin preparation for lactation

- stimulates uterine growth to accommodate growinfetus


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PRO#ESTERONE - “Hormone for Mothers”

- necessary to maintain endometrial lining of the ut

during pregnancy - reduces contractility of uterus during pregnancypreventing preterm labor

HUMAN PLACENTAL LACTO#EN (human chorionsomatomammotropin)

- with both growth promoting and lactogenic (milkproducing) properties

- promotes mammary gland (breast) growth inpreparation for lactation


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- regulates maternal glucose, protein and fat levels sthat adequate amounts of these are always available to thfetus

AMNIOTIC FLUID

800-1200mlSlightly alkaline pH 7.2

Fetal urine adds to its volume


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Functions:

Shields fetus against pressure or blow to the mother’sabdomen

Protects fetus from temperature change

Aids in muscular development because it allows fetus’freedom to move

Protects the umbilical cord from pressure protecting fetaoxygen supply


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Hydramnios – excessive amniotic fluid

- more than 2000ml or pockets of fluid larger th8cm on UTZ

Oligohydramnios – reduction in the amount of amnioticfluid

- less than 300ml or no pockets of fluid larger th

1 cm on UTZ


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AMNIOTIC

MEMBRANESChorionic membrane – the outermost fetal membrane;purpose is to form a sac that contains the amniotic fluid

Amniotic membrane – 2nd membrane lining the chorion

membrane; forms beneath the chorion - produces amniotic fluid

- produces phospholipid that initiates the formatof prostaglandins which can cause uterine contractions may be the trigger that initiates labor


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UMBILICAL CORDFormed from the amnion and chorion53cm (21 in) length; 2 cm thick

Wharton’s jelly – a gelatinous mucopolysaccharide thaforms the bulk of the umbilical cord giving it its body;prevents pressure on the veins and arteries

Outer surface is covered with amniotic membraneComposed of 1 vein (carrying blood from placental vilthe fetus) and 2 arteries (blood from fetus back to palcevilli)


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Blood flow is 350ml/min at term

Walls are with smooth muscles, nonerve supply

Function:Transports oxygen and nutrients to the

fetus from placenta and return wasteproducts from fetus to placenta

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