Exam 4 - Reproductive Flashcards
How is the egg swept up at the end of the fallopian tube
by cilia
How does the egg move through the fallopian tube
muscular contractions and the cilia
How long does it take from when the sperm enter the uterus to get the the fallopian tubes? Why?
30 minutes because the uterine muscles propel them
What is capacitation
when chemicals in the woman’s body alter the sperm to make them able to fertilize the egg
How long can sperm stay in the oviduct before fertilization
several days (1-2 wk)
Where does fertilization occur
In the oviduct
T or F Protein’s from the sperm’s cap must hook up precisely with proteins on the surface of the zona pellucida
true
How do the sperm get through the zona pellucida
they shed their outer coating releasing enzymes that allow them to enter
how many fertilized eggs do not result in viable embryos
over 50%
What happens to the zona pellucida once one sperm enters
It locks out all other sperm
When does the egg complete meiosis
After fertilization
How long until the first mitosis (post fertilization)
24 hours
After the first mitosis, how often do the cells divide
every few hours
How do you get identical twins
if the tiny group of dividing cells splits into two groups
How many days after fertilization does the blastocyst leave the zona pellucida? How?
6 days after fertilization it releases enzymes to break out
How is the blastocyst not destroyed?
It releases chemicals to suppress the mothers immune system
Where does the blastocyst go?
It becomes embedded in the endometrium
Why does morning sickness occur? Does everyone get it?
the changing hormones associated with pregnancy can cause it in some women
What is gastulation
the development of three germ layers
What do the three layers of the developing embryo become
Lower - lungs, liver, lining digestive tract (endoderm)
Middle - bone, blood, heart, and skeletal muscles (mesoderm)
Outer - CNS, skin and hair (ecotoderm)
When is it considered a fetus?
2 months after fertilization when all the organ systems are in place
T or F Maternal and fetal blood mix
False
T or F The heart works early in development
True
What do bones begin as?
Cartilage (from mesoderm/middle layer)
When does myelination begin occuring
6th month of gestation
How much does the mother’s blood volume increase?
50%
How much does the cervix open at birth?
4 inches
Before modern medicine, what was the common outcome of birth?
Death for the mother and the infant
T or F The human brain is bigger than that of primates, and the human pelvis is smaller than primates
True
Name the gonads for each sex and what is produced by each
Female - Ovary - ovum; steroid hormones: estrogen and progesterone
Male - testis - sprem; steroid hormone: testosterone
State what SRY stands for, where it is found, when and where it is expressed and what it do
Sex Determining Region found on the Y chromosome and expressed in the gonad for a few weeks only to cause the cells of the gonads to differentiate into male parts