Lecture 2 - Prenatal Development Flashcards
Time period between conception and birth
Gestation
How is gestational age calculated?
First day of mothers last menstrual cycle to current date
* NOTE: You’re not actually pregnant at the start of this (you get a couple extra weeks until ovulation where you get pregnant)
How is pregnancy calculated?
From when the egg and sperm meet
Which week of gestation is the egg released from the ovary?
Week 2 (only thing listed for week 2)
This is ovulation
Which week of gestation do sperm and egg meet in fallopian tube?
What is made when the egg and sperm meet
Week 3
NOTE: This is where the zygoat make
A Zygote has how many chromosomes?
46 (23 from mom, 23 from dad)
What is a blastocyst?
* What do the inner cells turn into
* What do the outer cells turn into?
Inner group of cells with an outer shell
Inner cells (embryoblasts) = embryo
Outer cells (trophoblasts) = placenta
* T for top
Is Mendelian genetics in the human body?
Somewhat common, but lots of things arent mendelian that we thought were
* things like eyes and hair are not on one gene
* This just means its on 1 gene
Dominant/Recessive genes are mendelian or polygenetic?
Mendelian
What are polygenic traits?
Controlled by two or more genes at different locations on different chromosomes
What are epigenetic expressions
External modifications to DNA that turn genes on/off
*However, it does not change the DNA sequence
Monozygotic twins are
identical
Dizygotic twins are
faternal
Blastocyte reaches uterus (embryoblasts) and implants on the uterine wall at which week?
Week 4
What is human chorionic gonadotropin production started and what is it used for?
Starts at week 4
Used to test for pregnany (what pregnancy tests pick up)
Remember, this is around the time that the woman is getting her period. If the woman wants to test 5 or 6 days before the start of the period its still going to be a negative test because the production of this hormone has not begun yet
* this hormone only starts after the blastocyte implants on the uterine wall (which is also week 4)
At which week do the ovaries stop releasing eggs and produce more estrogen and progresterone?
Week 5 (think after the period should’ve came)
* The body doesnt want to have multiple pregnancys at once
Is a negative pregnancy test 2 days before the period worth anything?
No, production of human chorionic gonadotropin has not begun, meaning the preganncy test won’t pick it up until production strats (week 4)
At which week do cells start dividing and taking on specific functions?
Week 5
At which week does the brain, spinal cord, and heart begin to develop? (along w/ GI tract)
week 5 (makese sense, cells start to take on functions here)
Which layer is the ectoderm and what 4 things does it have
Top layer
1) NS
2) Epidermis of skin
3) Epithelial lining of rectum
4) Oral cavity
Which layer is the mesoderm and what are the 6 things that it encompases
Middle layer
1) Musculoskeletal system
2) Dermis of skin
3) Cardiovascular system
4) Urinary system
5) Reproductive system
6) Outer layers of respiratory and digestive system
Which layer is the endoderm and what are its 2 things
Inner layer
1) Epithelial lining of digestive and respiratory tract and associated glands
2) Epithelial lining of urnary bladder
TEST which week does the neural tube close?
Week 6
What does the neural tube turn into?
Brain and spinal cord
What happens if the neural tube doesnt close?
Spinabifida / anacephalies