Episode 9: Major changes to the way Texas medical schools accept their students. You have to know this or you could be missed! Interview with Celeste Whisenant, a second year medical student who almost learned this lesson the hard way!
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Topics in this podcast:
Announcements
Introduction of Celeste Whisenant - covered in the audio only
The Dreaded Interviewer - [...]
a continuous process in the testis
in a normal male, there’s always mature sperm-in time.
in space, there are cells at different stages of maturation
continuous in time but discontinuous in different places along the seminiferous tubules
Looking at x.s.
the spermatogonia are closest to the basement membrane
the mature sperm-spermatozoa-are closest to the [...]
Questions
Which two substances inhibit GnRH secretion?
Dopamine and endorphins
What neurotransmitter stimulates GnRH secretion?
Norepinephrine
What is the rate limiting step in LH and FSH production?
GnRH dependent availability of the Beta subunit
What does GnRH require for its biological action on gonadotrophs?
Ca
Describe the GnRH to gonadotroph binding and activation process.
GnRH attaches to a plasma membrane glycoprotein receptor [...]
Gametogenesis- the process of meiosis and cytodifferentiation that converts germ cells into mature male and female gametes, spermatozoa and definitive oocytes respectively.
- timing between sexes differs
- diploid —– haploid
- 2n —– 1n
First meiotic division- involves DNA replication and recombination and yields two haploid 2n daughter cells.
- Primary oocyte or spermatocyte - the 4n cell [...]
At fertilization, the sperm nucleus enters the oocyte, the oocyte completes meiosis, and the pronuclei of the two mature gamates fuse. Fertilization is a complex interaction between sperm and oocyte. If viable sperm encounter an oocyte in the ampulla of the oviduct, they surround it and force their way through the cumulus mass.
When the [...]
1) Engagement - Bi-parietal diameter (BPD) descends through the plane of the pelvic inlet.
2) Descent
3) Flexion - chin tuck to decrease the diameter passing through the pelvis
4) Internal Rotation - rotates past the spines
5) Extension - keep occiput in contact with the pubic arch
6) External Rotation - will turn same way as internal [...]
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