special populations fertilization

how many haploid spermatocytes are involved in fertilization

23 (either X or Y)

how many haploid oocytes are invovled in fertilization

23 (all x)

how many total diploids are involved in fertilization

46 (fertilized egg)

how many pairs of chromosome determine sex

one

how many non sex chromosomes are there 

23 

what is the fertilization process

egg travels alone tube

egg lives up to 24 hours

sperm travels up uterus

sperm reaches egg in 5 min

100-200 sperm reach egg

sperm lives up to 5 days

what is the most common site of fertilization

ampulla

what are the phases of chemical reactions for fertilization 

capacitation 

acrosome reaction 

fusion 

what happens during capacitation

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

what happens during the acrosome reaction phase

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

what does fusion occur between 

oocyte and sperm plasma membrane 

what happens during the zona reaction

enzymatic reaction changes to block other sperm

what is produced when fertilizatoin occurs

zygote

what happens during cleavage 

division of cells

what happens in the morula during cleavage

16 cells after 72 hours

what is the order of forms during fertilization

zygote

morula

blastocyte

implantation

describe a blastocyst 

morula forms cavity and fills up with fluid

what do trophoblast cells do

secrete HCG

what does the HCG feedback go to 

corpus luteum 

what does the HCG feedback loop do

maintain the endometrium

how often do HCG levels double in the first trimester

every 24 hours

what forms on the inner mass 

embryonic disc 

when does implantation occur

7th day after fertilization

where is the ideal site of implantation

posterior superior fundus

what kind of cells embed into the endometrium 

trophoblast cells 

what happens during nidation

trophoblast buries itself into the decidua

trophoblast cells split into 2 different tissues

how many tissues do the trophoblast cells split into

placenta membrane

fetal membranes

where is the syncytiotrophoblastic layer 

outer layer of placental membrane 

what does the syncytiotrophoblast layer invade

decidua

what does teh syncytiotrophoblast layer form

pool filled with maternal blood

what is the syncytiotrophoblast layer called 

lacunae 

what is the placental membrane

syncytiotrophoblast layer

what is the fetal membrane

cytotrophoblast layer

where is the cytotrophoblast layer

inner layer of the fetus

what does teh cytotrophoblast layer form 

chorionic villi 

villi deep into the lacunae 

what does nitabuchs layer prevent

further digestion of the decidua/endometrium

what do the amnion and chorion fuse to form

aminochorionic membrane

what makes up the aminochorionic membrane 

amnion and chorion 

when is the placental fully formed by

14 weeks of gestation

how long does the placenta work for

40 weeks

do fetal and maternal blood mix 

no 

what does the placenta form

cotyledons

what is the placenta the site of

nutrient, gas, and waste exchange

what does simple diffusion exchange 

CO2 and O2 

what does facilitative diffusion require

need a carrier like glucose 

what does active transport exchange

amino acids and proteins

goes against gradient and requires energy

what does pinocytosis transport

cholesterol

IGg

when do HCG levels decrease in the placenta 

during second trimester 

what hormones does the placenta secrete

progesterone

estrogen

where is the amniotic membrane

innermost membrane

encloses the fetus

what are the characteristics of the amniotic membrane 

smooth 

encloses fetus 

contains amniotic fluid

connect with fetus at umbilicus 

what is the function of amniotic fluid

protect fetus against injury

sterile

maintain fetal temperature

allow fetal movement

avoid adhesions of fetus on membrane

receive waste

what is the fluid turnover rate for amniotic fluid

3 hours

what is amniotic fluid derived from 

amniotic cell but also maternal blood 

what is polyhydraminia

>2 liters of amniotic fluid

GI and other malformations

what is oligohydramnios

<1 liter

fetal renal abnormalities

what does the umbilical cord contain 

2 umbilical arteries 

1 umbilical vein 

what do the umbilical arteries carry

CO2

what does teh umbilical vein carry

O2

what surrounds teh umbilical vessels 

wartons jelly 

what is teh umbilical cord

pliable cord made of connective tissue

what is the approximate size of the umbilical cord

20 inches long

2 cm wide