Fertilization

how many haploids are in spermatocyte and oocyte?

23 each

how many diploids are in a ferilized egg?

46

what is the normal chromosome amount?

22 pairs of non sex chromosomes and 1 pair that determines sex 

what is the fertilization process?

migration — egg travels along tube and lives for up to 24 hours, sperm travels upward in the uterus and reaches the egg within 5 minutes, sperm lives up to 5 days, 500-600 sperms reach the egg 

where is the most common site for fertilization?

ampulla

what is capacitation?

physiological and biochemical change in the head of the sperm before entering the egg

what is the acrosome reaction?

sperm releases enzymes to penetrate the corona radiate and zona pellucida of the oocyte

hyaluronidase and acrosin

what is the zona reaction?

zona pellucida undergoes enzymatic change to block out other sperms 

what is formed once fertilization occurs?

zygote

what occurs during cleavage?

division of cells, forms morula

what is the morula?

16 cells after 72 hours

what is the process of fertilization in order?

zygote, morula, blastocyst and implantation 

how does the blastocyst form?

the morula forms a cavity and will up with fluid

where are trophoblast cells fromed?

the blastocyst

what doe trophoblast cells secrete?

HCG and form placenta

what is the HCG+ feedback doing in the blastocyst?

feedback to the corpus luteum to secrete progesterone in order to maintain endometrium 

how much should HCG levels rise in the first trimester?

they should double every 24 hours

what is the inner cell mass formation of the blastocyst?

embryonic disc

how many days after fertilization does implantation occr?

7

where is the ideal location for implantation? 

posterior superior fundus 

what embeds into the endometrium during implantation?

trophoblast cells

what does the endometrium become after implantation?

decidua

what are the layers of the decidua?

decidua basilis, capsularis and vera

what layer of the decidua does the fertilized egg implant?

decidua basalis 

what occurs during nidation?

the trophoblast buries itself into the decidua and splits into two different tissues

what tissues does the trophoblast split into?

placental membranes and fetal membranes

what is the syncytiotrophoblast layer?

the outerlayer of the placental membrane towards the maternal bllod

what does the syncytiotrophoblast layer of the placenta do? 

invades the decidua, digests blood vessels and forms a pool filled with maternal blood called the lacunae 

where is the cytotrophoblast layer of the fetal membrane?

the inner layer that faces the fetus

what does the cytotrophoblast layer form?

the chorionic villi deep into the lacunae

what layer of the of the cytotrophoblast prevents further digestion of the decidua/endometrium?

nitabuch’s layer 

what else is found in the cytotrophoblast layer?

amnion membrane and umbilical cord

what forms the amniochorionic membrane?

amnion and chorion

when is the placenta fully formed?

by 14th week of gestation

how long does the placenta work?

40 weeks 

what is a crucial point in regards to the planceta?

the blood between mother and fetus DO NOT mix

what is formed in the placenta?

cotyledons

what is the placenta the site of?

nutrient, gas and waste exchange

what are the functions of the pacenta?

secrete hormones, respiratory, excrete waste like urea and nutritional, trasmission of maternal antibodies 

what is the innermost membrane enclosing the fetus?

amniotic membrane

what is true of the amniotic membrane?

it is smooth and contains amniotic fluid

what does the amniotic membrane connect?

with fetus at umbilicus

what are the functions of amniotic fluid?

protects fetus from injury, sterile, maintain temperature, allow free fetal movements, avoid adhesions, receives waste 

how often is the amniotic fluid turnover?

~ 3 hours

what is the normal amount of amniotic fluid?

2 liters

what does the umbilical cord contain?

2 umbilical arteries and one umbilical vein that connects the embryo and the placenta

what do the umbilical arteries carry?

CO2

what does the umbilical vein carry?

O2

what surrounds the vessels of the umbilical cord?

warton’s jelly

what is the length and diameter of the umbilical cord?

20 inches long diameter of 2 cm

what does amniotic fluid mainly come from?

fetal urine 

what is the ideal placenta location?

superior and posterior

what is polyhydramnios?

more than 2 liters of amniotic fluid

what does polyhydramnios indicate?

GI issue

what is oligohydramnios?

less than one liter of amniotic fluid 

what does oligohydramnios indicate?

fetal renal abnormalities

what types of transport does the placenta allow for?

simple diffusion, facilitative diffusion, active transport, pinocytosis

what is transported with simple diffusion at the placenta?

CO2 and O2

what is transported with facilitative diffusion at the placenta?

glucose

what is transported with active transport at the placenta?

amnio acids and proteins 

what is transported with pinocytosis at the placenta?

cholesterol and IgG