B3 Flashcards
fertilization step 1
Sperm cells release enzymes from acrosome cap to digest the egg’s outer coating.
Fertilization step 2
Sperm move closer through the coating to the plasma membrane.
Fertilization step 3
Egg’s plasma membrane depolarizes after one sperm enters, blocking others.
Fertilization step 4
Sperm and egg nuclei fuse, forming a zygote with 46 chromosomes.
vitro fertilization
FESFI
contraceptions
E & P inhibit FSH & Lh = no ovulation
- Thick cervical mucus
-tubal ligation
prevents egg from moving from ovaries to uterus = no fertilization
Vasectomy
Vas deferens cut
cleavage
division without cell increasing
3 division stages
zygote - morula - blastocyst
morula
when zygote reaches 16 cells ( day3)
bastocyst
morula reaches uterus ( day 5)
trophoblast
extraembryonic structure
embryoblast
develops into embryo
order of being pregnant
F.I.P
implantation
5-7 days after fertilization
-blastocyst attaches to endometrium and secretes enzyme
- implantation completed by day 10-14
Trophoblast secretes
HcG
HGC
same affects as LH
-maintains corpus luteum
- so E & P stay high
what does HCG prevent
menstruation
how long is HGC secreted for
3 months, then placenta secretes E & P
when does trophoblast become embryonic structure
2nd week
amnion
insulates, hydrates, protects
yolk sac
early red blood & digestive tract formation
chorion
secretes HCG
- controls passage of nutrients, gases & waste
allantois
forms foundation of umbilical cord
placenta
metabolic exchange between baby and mothers blood
what does placenta produce
E & P by the third month
hormone levels in pregnancy
1.high, norm, norm
2. low, norm norm
3.low, high high
morphogenesis
embryo development
differentiation
cells begin to take shape and grow
gastrulation
inner mass of cells forming layers
what is embryo called in 2nd week
gastrula
endoderm
lining of digestive system, organs, resp and endo glands
mesoderm
muscles, skeleton, reproductive
ectoderm
nervous system, epidermis (skin)
what is developed during first trimester
heart,brain, limbs, SC, handds and feet, (not functional yet)
what is developed during second trimester
NS connections, more development and growth of everything
what is developed during third trimester
rapids growth, organ maturation, immune system
relaxin
causes ligaments to loosen cervix
oxytocin
from PP, contractions and pos feedback
what is released during labour
prostaglandings and low progesterone
lactation
breast milk, high E & P prepares for lactation
prolactin
ANt pit, stimulates mammary glands to produce
stops FSH & Lh
colostrum
after birth lots of benefits