Lecture 2: Introduction and Gametogenesis Flashcards
What are the 4 phases of spermiogenesis?
- Golgi phase
- Cap phase
- Acrosomal phase
- Maturation phase
In which phase of spermiogenesis does the sperm rotate so that the acrosomal pole faces the wall of the semineferous tubule?
Acrosomal
What are the important acrosomal enzymes that are involved in spermiogenesis?
Hyaluronidase
Zona lysin
What are the functions of sertoli cells?
- physical support and maintenance
- maintain and coordinate spermatogenesis
- secrete estrogen, inhibit, and antimullerian factor
- maintain the blood testis barrier
- secrete tubular fluid
- phagocytize residual bodies of sperm cells
Describe the blood testis barrier
protects the maturing form from the rest of the blood in the body
sperm are protected by the sertoli cells, eventually it has to be broken down so that the sperm are set free
stimulated by testosterone
Describe the various hormonal interactions that lead to sperm cell production (LH)
GnRH is secreted from the hypothalamus which allows secretion of LH from the anterior pituitary which binds to receptors on the interstitial cells of Leydig who synthesized testosterone who travels through the blood to other tissues to create an effect
Describe the various hormonal interactions that lead to sperm cell production (FSH)
GnRH is released from the hypothalamus which allows the anterior pituitary to release FSH which then goes and binds to the receptors on Sertoli cells. These cells convert testosterone to estrogen and produce androgen binding proteins and inhibin
Describe the sperm transport AFTER spermiogenesis
passive transport in the testicular fluid, muscle contractions, and cilia in the tubules
Where do the sperm mature and how long does it take?
Head of the epididymis; sperm are capable of fertilization by the time they reach the tail of the epididymis
Describe the ejaculation path
ductus deferens
fluid is added from the seminal vesicles and the prostate
Describe the sperm transport in the female including the pH along the way
- upper vagina (4.3-7.2)
- cervix (6.0-6.5; optimal for motility)
- cervical canal (mucous block; changes from thick to thin in the middle of the menstrual cycle (ovulation)
- Isthmus: capacitation occurs; sperm move up the oviduct
FERTILIZATION occurs in the ampulla
Describe the egg transport in the uterine tube
- fijmbraie of the uterine tube moves closer to the ovary and sweeps the surface (increase ciliation and activity of tube epithelial and muscle cells)
- capture of the egg and surrounding follicles
- transport of egg via contraction of smooth muscle
takes about 3 days (req progesterone)
What are the 2 types of spermatogonia?
Type A- sperm cells
Type B- leave mitotic cycle and enter meiotic
