Cellular Division, Fertilization, and what happens in Embryo at Implantation

mitosis

growth and tissue repair, cells in body divide and replicate themselves

meiosis

eggs and sperm cells that contain half the genetic material of chromosomes

gametogenesis

production and maturation of gametes

oogenesis

female gamete, all ova present at birth

spermatogenesis

male gamete, starts at puberty

ova fertility

12-24 hrs after ovulation

sperm life

48-72 hrs, fertile for 24

fertilization

occurs in ampulla of fallopian tube and chromosomes pair to create diploid zygote

female vs male chromosome

F- XX

M- XY

embryonic membranes

begin to form at time of implantation and help to protect and support the growing embryo

chorion

outermost membrance

chorionic villus

finger-like projections in the chorion

amnion

membrane that holds amniotic fluid

yolk sac

nutrition and gas exchange occur here before placenta forms

fraternal twins

2 separate eggs and sperm, babies don't share anything

identical twins

1 egg and sperm, blastocyte splits into 2 and depending on when it splits determines what babies share

monochorionic diamniotic

single placenta, 1 chorion, 2 amnion, fight for placenta

monochorionic monoamniotic

single placenta, 1 chorion, 1 amnion, worry about cord accidents

dichorionic diamniotic identical

fused placenta, 2 chorions, 2 amnions

dichorionic diamniotic fraternal

separate placenta, 2 chorions, 2 amnions, only share uterus

amniotic fluid

cushions fetus and umbilical cord, controls temp, allows fetus to change position, promotes growth and development

amniotic fluid is made of

albumin, vernix, fetal urine, uric acid, lecithin, sphinogomyelin

polyhydramnios

more fluid than anticipated for either the gestation age of pregnancy of >2,000 mL

oligohydramnios

umbilical cord

body stalk connecting placenta with fetus containing 2 arteries and 1 vein, surrounded by Wharton's jelly, and twisted

umbilical cord vein

carry oxygenated blood from placenta to baby

umbilical cord arteries

carry deoxygenated blood and waste from baby to placenta

does the umbilical cord cutting hurt

no because there is no sensory or motor innervation

why is the umbilical cord twisted

fetal movement

main placental function

immunologic properties that protect against antibody production since homograft (transplant of living tissue)

other placental functions

excretion of waste, deliver O2 to baby, fetal nutrients, hormones

fetal nutrients created by placenta include

glycogen, cholesterol, fatty acids

adaptations of blood flow while pregnant

umbilical vein, ductus venosus, foramen ovale, ductus arteriosus, umbilical artery

placenta for blood circulation

mom's blood pools and baby arteries stick into this pool to pick up oxygen

umbilical vein

carry O2 and blood back to the liver

left branch of umbilical vein

go into liver, long route

right branch of umbilical vein

includes ductus venosus which allows blood to go right to the IVC and right atrium

what happens after blood goes into RA and mixes with blood from SVC and IVC

1. go to left ventricle then the lungs but because of resistance, it causes pressure on right side of heart

2. pressure pushes blood across foramen ovale into left atrium

ductus arteriosus

allows blood to go from the pulmonary artery to the aorta bc of its high pressures from resistance in the lungs

umbilical artery

brings blood back to placenta bc has low resistance which makes blood go toward it