Ch 33 Flashcards
(41 cards)
What structure begins the production of sperm?
Testis, testes plural
Where is sperm matured
Epididymis
What hormones stimulate sperm production
FSH and testosterone
What is the result of gastrulation
3 cell layers
Which smooth muscle helps remove endometrium
Uterus
How long does a menstrual cycle last
28 days
What is a human zygote
one celled human, only for about 24 hours
What is a human embryo
multiple celled; till 9 weeks
What is a human fetus
After 9 weeks
What surrounds an egg while in ovary
follicle
What is the function of the scrotum
It helps the protein in the sperm from becoming denatured by holding the testes outside the body so they don’t get too hot
What are the steps in the process of fertilization
When the nuclei of a sperm and egg fused, is considered fertilized, happens in ovaries.
c. Sperm swim up uterus to oviducts
d. Acrosome of one sperm fuses with plasma membrane of secondary oocyte (egg)
e. Oocyte completes Meiosis II
i. Producing a mature ovum
1. Haploid
f. Ovum and sperm nuclei fuse
i. Forming diploid zygote
Then turns into zygote, one celled human. First cleavage turn it into two celled human, embryo. Then turns into hollow ball, blastocyst. Egg travels through oviducts with rhythmic cilia movements. Egg (ovum) is implanted in uterus
Describe fraternal and identical twins
a. Fraternal 2 eggs / 2 sperm with different genetic make-up
b. Identical twins are from 1 egg and 1 sperm where in the early stage of development the cells split
Know the structure of the sperm
a. Head
i. Acrosome at tip
1. Has enzymes to fuse with plasma membrane of ovum
ii. Nucleus with genetic material
b. Midpiece
i. Lots of mitochondria to supply ATP to the Tail
ii. Breaks off, so no paternal mitochondrial DNA contributed to the new H. sapiens
c. Tail
i. Flagellum that propels the sperm
What is the function of the placenta?
Acts as a barrier between mother and child. Allows nutrients in, no waste, child’s waste is put through into bloodstream. Barrier to waste but not drugs
Describe the menstrual and ovarian cycles, including hormonal changes (be able to read and interpret the graph)
yee
What is testosterone needed for?
a. Make sperm
b. Creates secondary sex characteristics
i. Deep voice
ii. Stronger muscles
What conditions are needed for fertilization to occur?
a. Egg needs to be viable (~24 hour time period)
b. Sperm need to be viable (~10 hours)
Where does fertilization usually occur?
In the oviduct
What is the purpose of mitochondria for sperm cells, and do they enter the ovum?
They don’t enter the ovum and they power the flagellum of a sperm cell.
What happens to the cilia of a smoking woman
They slow down and can get implanted into oviducts
What are cilia
Small hair like flagella on side of egg that rhythmically push egg through oviduct and into uterus
What are potential consequences of damaged cilia?
Ciliary activity is reduced so
i. Oocyte might not make it into oviduct
ii. Ectopic pregnancy risk is greater because embryo may implant in oviduct
What induces the shedding of the endometrium?
Decreasing progesterone and estrogen levels
