Cell reproduction and the Continuity of Life: Fertilization and development processes Flashcards
Test review
What happens during ovulation?
Cilia in the fallopian tube create a current to draw the egg towards the oviduct.
When and where does fertilization occur?
Occurs within 24 hours of ovulation in the upper fallopian tube.
What are some details about sperm in fertilization?
Millions enter the female reproductive tract. Only one fertilizes egg. They survive 48-72 hours in the female body. The egg completes meiosis immediately after the sperm penetrates, forming a haploid nucleus. The haploid sperm deposits genetic material to the egg and forms a diploid zygote.
What happens after the sperm enters the egg?
Electric and chemical properties of the egg membrane change preventing further entrance of sperm.
What happens post fertilization?
The zygote continues toward the uterus, dividing all the while but not increasing in size. (cleavage) This continues until a rounded hallow ball of cells (blastocyst) is formed.
What does the zygote become during cleavage?
An embryo.
What is the solid mass of identical cells formed during cleavage?
A morula.
What is the difference between a blastula and a blastocyst?
Blastula is the general term, blastocysts are for mammals.
What are the cell groups formed during division?
Inner cell mass - Group of cells in a part of the blastocyst which form the baby and the amnion (blastocoel)
Trophoblast - The layer of cells surrounding the blastocoel, whose cells form the chorion which become the placenta. Also secretes hCG
When does the blastocyst embed into the endometrium?
At the end of the first week, where it begins to form the into the fetus.
How long does the corpus luteum secrete progesterone after fertilization?
3 weeks, to maintain the endometrium.
What happens during the second week of fertilization?
Embryo cells undergo gastrulation (form 3 layers) and becomes a gastrula.
What are the 3 gastrula layers and what do they form?
Ectoderm - Forms skin, nervous tissues, and sense organs
Mesoderm - Forms kidneys, skeleton, muscles, blood vessels and gonads
Endoderm - Forms the lungs and the lining of the digestive tract
What do the mesoderm and ectoderm develop in neurulation?
The mesoderm forms a rod called the notochord. Ectoderm forms nervous system on top of them.
What do cells above the notochord do?
Fold in two regions until the fuse and form a hollow nerve chord.
