OB - FERTILIZATION

Fertilization conception impregnation fecundation

union of ovum (24-48 hours) and spermatozoon (48-72h)

fertilization

occurs at the outer third of the fallopian tube (ampullar portion)

ampullar portion

where fertilization occurs

pre-embryonic, embryonic, fetal

3 period of fertilization

pre-embryonic

first 2 weeks

embryonic

3-8 weeks

fetal

8 weeks to birth

during penetration

a single sperm penetrates the cell membrane of the oocyte

during penetration

2.5 ml per ejaculation containing 50-200m spermatozoa/ml

1000-3000

can actually reach the ampulla

1 spermatozoa

amt that can penetrate the ovum

flagella, uterine contractions thru cx, life span 48-72h after ejaculation

spermatozoa move by means of:

fornix

area where the sperm deposited after ejaculation

gynosperm

x chromosome carrying sperm with large oval head (female)

androsperm

y chromosome carrying sperm cell with small head (male)

two layers covering the ovum

protects the oocyte from fertilization by more than one sperm and increases the bulk of the ovum which facilitates migration to the uterus

corona radiata

a layer of follicle cells on the outside of the secondary oocyte (circle of cells)

zona pellucida

an extra-cellular matrix of glyco-proteins which binds with acrosome of the spermatozoon

zona pellucida

triggers the acrosomal reaction

zona pellucida

the acrosome bursts, releasing enzymes (acrosin) that help the sperm get through the zona pellucida

mature ovum

completion of second meiotic division of the oocyte (transformation -fusion of cell membrane)

pronucleus

nucleus of the oocyte (transformation -fusion of cell membrane)

sperm tail

degenerates (transformation -fusion of cell membrane)

mitochondria

degenerates (transformation -fusion of cell membrane)

zygote

1st cell of the human body

ovum

fetal growth from ovulation to fertilization

graafian follicle

ovum is extruded from

fimbrae

ovum is propelled into fallopian tube by currents initiated by

24 hours

capable of fertilization

atrophies; non functional

unfertilized ovum

zygote

fetal growth from fertilization to implantation

zygote

travels towards the body of the uterus— the muscular contractions of the fallopian tubees (3-4) days

cleavage of mitotic cell division

within 24h until it reaches the body of the uterus

morula

bumpy outward appearance consist of 16-50 blastomeres

16-50 blastomeres

morula compostion

blastocyst

the morula that multiplied and continued to float in the uterus until it attaches to the uterine endometrium

embryo

fetal growth from implantation to 5-8 weeks

implantation

contact between the blastocyst and the endometrium (8-10 days after fertilization) which occurs in three phases

apposition, adhesion, invasion

3 phases of implantation

apposition

blastocyst brushes against the endometrium

adhesion

blastocyst attaches to the surface of the endometrium

invasuib

blastocyst settles down into the soft folds of the endometrium

fetus

5-8 weeks until term

conceptus

placental structures

fetus

mother carries the unborn child for 9 months which it undergoes continuous fetal development including its placental structures

conceptus

placental structures

decidua parietalis

remaining portion of the endometrium

decidua basalis

lying directly under the embryo/maternal side of the placenta

decidua capsularis

grows over the embryo on the luminal side

decidua capsularis

surrounds the embryo together with decidua basalis

chorionic villi

fingerlike projections around the zygote develops by the 10th to 11th day of pregnancy

2 layers pf chorionic villi

syncytial layer and langhan’s layer

cytotrophoblast

present as early as 12 days of gestations

cytotrophoblast

inner layer which protects the fetus against syphilis and capable of living until 24 weeks or 6 months

cytotrophoblast

disappears between 10 to 24 week

syncytiotrophoblast

forms the fetal side of placenta

syncytiotrophoblast

the outer layer (produces placental hormones (HCG HPL (somatomammotropin), estrogen, progesterone

produces placental hormones (HCG HPL (somatomammotropin), estrogen, progesterone

he outer layer (produces placental hormones (HCG HPL (somatomammotropin), estrogen, progesterone what does the outer layer of syncytiotrophoblast produce

2 layers of syncytiotrophoblast

amnion and chorion

amnion

innermost membrane of placenta

amnion

smooth, thin, tough and translucent membrane directly enclosing the fetus and the amniotic fluid

amnion

where the umbilical cord and amniotic fluid are developed

funis

AKA Umbilical cord

umbilical cord

5-55 cm long and 2 cm in diameter of whitish gray cord which joins fetus to placenta. dull, white, moist

umbilical cord

provides circulatory pathway

umbilical cord

part of amnion with no nerve supply

umbilical cord

rate of blood flow is rapid (350ml/min)

umbilical cord

composed of 2 arteries (unoxygenated blood) and 1 vein (oxygenated blood) (AVA)

wharton’s jelly

a gelatinous mucopolysaccharide bulk of the cord

wharton’s jelly

gives the cord body and prevents pressure on veins and arteries

amniotic fluid

bag of water

amniotic fluid

clear, musty or mousy odor with crystallized ferning pattern PH 7.2

1.005-1.025

alkalinity of amniotic fluid

500-1000 cc

normal amount of amniotic fluid

green-tinged AF

meconium stained AF

golden-colored

hemolytic disease AF

Fetal death

brownish, coffee, or tea-colored AF