Kuehn - Gamete Development/Fertilization Flashcards
3. explain the origin and structure of both the embryonic disc and the yolk sac.
<p>How is an oocyte transported to the ampulla?</p>
<p>after rupturing the outer epithelium of the ovary, enters peritoneal cavity, cumulus oophorus is hooked by cilia and pulled into infundibulum, via peristalsis is then pulled into ampulla</p>
<p>How long can an oocyte remain in the ampulla?</p>
<p>12-24hrs</p>
<p>How do sperm enter the ampulla after being deposited in birth canal?</p>
<p>combination of uterine peristaltic movements and sperms own chemotaxis(motility) towards oocyte</p>
<p>What part of the oocyte degrades in the ampulla? </p>
<p>the cumulus oophorus degrades into corona radiata</p>
<p>When does fertilization begin?</p>
<p>sperm reaches corona radiata of oocyte, passes through and attaches to Zona Pellucida</p>
<p>What glycoproteins help the sperm to bind to Zona Pellucida?</p>
<p>ZP3</p>
<p>What does the sperm release from its acrosome?</p>
<p>enzymes that digest Zona Pellucida</p>
<p>What happens once the sperm has penetrated Zona Pellucida?</p>
<p>fusion of sperm and oocyte membranes occurs</p>
<p>What makes Zona penetration by a second sperm unlikely?</p>
<p>when zona is penetrated there is a release of cortical granules from oocyte preventing a second intruder (Ca++ mediated)</p>
<p>What occurs in order for pronuclei to fuse into a single nucleus?</p>
<p>oocyte completes second meiotic division = female pronucleus
sperm nucleus becomes male pronucleus</p>
<p>The fused pronuclei are now technically what?</p>
<p>a zygote</p>
<p>What is the acrosome of a sperm?</p>
<p>the head which contains digestive enzymes that aide in oocyte fertilization</p>
<p>What contains the sperms haploid DNA (N) in condensed form?</p>
<p>the nucleus within the head</p>
<p>What contains the mitochondria of the sperm?</p>
<p>the Mid-piece</p>
<p>What does the mitochondria do for the sperm?</p>
<p>powers the flagellum for motility</p>
<p>What part of the sperm contains microtubules for motility? </p>
<p>the tail</p>
<p>What cell does spermatogenesis begin with and they only divide by which method?</p>
<p>begins with stem cell - Type Ad spermatogonium
| ALL spermatogonia divide by mitosis</p>
<p>What is the product of Type Ad spermatogonium division?</p>
<p>1 - Type Ad spermatogonium
| 1 - Type Ap spermatogonium</p>
<p> Type Ap spermatogonium further divide by mitosis and differentiate into what?</p>
<p>Type B spermatogonia (terminal differentiation) which divide by mitosis into primary spermatocytes</p>
<p>How do the primary spermatocytes form into secondary spermatocytes?</p>
<p>they divide by meiosis in Division I (reduction division)</p>
<p>What is formed when the secondary spermatocytes undergo Division II of meiosis?</p>
<p>Spermatids (round cells) are formed! (genetically mature gametes - not physically mature)</p>
<p>What occurs after morphological differentiation of spermatids (spermiogenesis)?</p>
<p>nucleus condenses and Normal sperm forms = mature Spermatozoan</p>
<p>What triggers the spermatids to mature?</p>
<p>a response to Bcl2-family gene products</p>
<p>What are follicles?</p>
<p>they contain oocytes, throughout their development, and follicular cells</p>
When do oogonia complete differentiation into primary oocytes?
oogonia is only found in fetus and completes differentiation by birth
When does the primary oocyte begin to form a secondary oocyte?
it remains in Prophase of Division I until a signal initiates further development
Where are the secondary oocytes found?
only in final stage of Graffian follicle, just before ovulation (1 day or so)
What is a primordial follicle?
only one thin layer of follicular cells
What is a primary follicle?
cuboidal layer of follicular cells
What is a secondary follicle?
a growing follicle with primary oocyte
What is a mature/antral/graffian follicle?
it contains antrum and primary/secondary oocyte
After fertilization what occurs in the zygote?
cells rapidly manufacture new proteins(microtubules, histones, and enzymes) and the DNA replicates
When does the zygote move into the uterine tube?
after about 30 hours and undergoes first cleavage into two blastomeres
