Reproductive Part 2 Flashcards
(43 cards)
What are the 3 fertilization steps called
#1: Capactitating #2: Acrosmal Reaction #3: Fertilization
What is Capactitating and what happens here
First step of fertilization.
- acidic vagina causes acrosomal pores to open
- sperm membrane receptors detect chemicals released by the egg
What is acrosomal reaction and what happens
Second step of fertilization.
- enzymes realeased by acrosome digest the outer membrane of egg
What is fertilization and what happens
Final step of fertilization
- sperm fuses with plasma membrane of the ovum
- sperm goes into cytoplasm causing electrochemical reactions in egg
- membrane of egg becomes impermeable
How does pregnancy happen
Zygote undergoes mitosis while moving down the oviduct. 8 cells make a morula which is undifferentiated. By the time it goes to uterus it’s differentiated.
Zygote is now called a blastocyst with embryo in the middle
What is a morula
8 undifferentiated cells which differentiate upon reaching uterus
What is blastocyst, where does it embed
Zygote becomes blastocyst, and it has embryo in the middle. It embeds in endometrium
What happens during implantation
During implantation, blastocyst embeds in endometrium and the outer layer releases hCG
hCG function
- stops corpus luteum from degenerating for 3 months.
- makes progrestrone/estrogen despite the lack of FSH and LH
- prevents contractions of uterus, endometrium maintained
Define chorion
- Outermost membrane secreting hCG
- Part intermingling with endometrium forms placenta
define placenta
Specialized part of chorion
- contains meternal & feternal vessels
- allows diffusion of gasses, nutrients, and water
- continues production of hCG, progesterone, and estrogen
- maintains endometrium
define amnion
Innermost membrane next to baby
- has amniotic fluid to cushion baby
- protects embryo from trauma & temp fluctuations
- allows baby freedom to move so limbs don’t stick to body
define allantois
Helps embryo exchange gasses & handles wastes
- sends umbilical blood vessels to placenta
define umbilical cordà
Connects mother to baby
Connects from belly button to placenta
- carry blood to and from placenta
define umbilical cord
Site of early blood cell formation, contributes to permative digestive tract
Embryonic development (gastrulation)
Happens when embryonic cells start producing 3 layers
What do layers produced by embryonic cells do
Ectoderm - outer layer: skin cells & nervous systems
Mectoderm - middle layer: keleton, muscles, and reproductive structures
Ectoderm - inner layer: digestive, respitory, and endocrine systems
define human gestation
Human gestation are pregnancy months divided into 3 trimesters
What happens during 1st trimester of human gestation and how long is it
It’s from fertilization to week 12
- zygote become blastocyst
- organs are developed
- heart starts beating by week 4
- testosterone is produced by week 7 if Y chromosome
- all basic adult structures developed by week 8
- embryo becomes fetus, about 9cm long
- really sensitive
What happens during 2nd trimester of human gestation and how long is it
From week 13 to week 24
- rapid growth
- fetus really active
- hair growth
- skeleton carriage replaced by bones
- 30cm at the end
What happens in 3rd trimester of human gestation how long is it
From week 25 to week 38
- rapid growth
- fetus activity decreases due to lack of room
- mature and ready to come out
- 50cm at the end, 3kg
Steps of pasturation
#1: labour #2: delivery #3: childbirth
What happens during labour
- involuntary rythmic contractions of uterus
- cervix opens up and diallates
What happens during delivery
- involuntary uterine contractions
- voluntary abdominal contractions
- mother forces baby out of cervix and vagina
