15.1- fertilization and embryonic development Flashcards
developmental changes are divided into what 2 stages
embryonic and fetal
embryonic period consists of ___
rapid cell division, organs form, supporting structures form
fetal period consists of
rapid growth, organs function, systems form
fertilization is AKA
conception
fertilization=
fusion of sperm and egg to form a single cell with 46 chromosomes (23 pairs)
how many chromosomes does a human have
46`
how many pairs of chromosomes does a human have
23
how does the egg travel down the oviduct (2)
peristalsis and cillia
after the egg is released during ovulation, how many days does it take to reach the uterus
4 days
how many hours does the egg have to get fertilized and where does it take place
24 hours
oviduct
what kills and/or loses many sperm (2)
the females acidic and some sperm travel into the wrong oviduct
what allows the sperm to enter the egg
enzymes located in the acrosome (head)
the egg is surrounded by which 2 layers
1- zona pellucida
2- corona radiata
what is the zona pellucida
clear layer of protein and carbs surrounding egg plasma membrane
what is the corona radiata
follicle cells surrounding the zona pellucida that nourish the egg in the ovary
sperm must break through which 2 layers to enter the egg
- zona pellucida
- corona radiata
what happens when one sperm enters the egg
one sperm enters- plasma membrane depolarizes- no more sperm can enter
what is a zygote
first diploid 2n pair
hows a zygote created
23 chromosomes from each gamete combine to form 23 chromosomes pairs
what happens during cleavage
the single celled zygote begins to divide but stays the same size (1 cell-2cells-4cells…)
what’s a structure composed of 16 undifferentiated cells called
morula
morula reaches the uterus ___ days after fertilization
4