Reproductive Physiology of the Male & Fertilization Flashcards
Testosterone is made in the ______
LH cell
The formation of spermatozoa in the seminiferous epithelium starts near the _____
basement membrane
The spermatogonium divide to form other spermatogonia and ultimately _______
primary spermatocytes
The primary spermatocytes are moved from the basal compartment through the tight junctions from adjacent Sertoli cells into the adluminal compartment where they eventually divide to form ________ and _________.
spermatocytes
spherical spermatids
Where is testosterone converted to estradiol?
sertoli cells
Define spermatogenesis
process of producing spermatozoa in the seminiferous tubules
List the benefits of spermatogenesis
provides a continual supply of male gametes
provides genetic diversity
provides billions of sperm each day
provides an immunologically privileged site (Blood Testes Barrier)
T/F: Developing germ cells are not destroyed by the male’s immune system
TRUE
What are the three phases to spermatogenesis?
proliferation
meiotic phase
differentiation phase = spermiogenesis
Define profliferation
mitotic divisions
Define meiotic phase
involves primary and secondary spermatocytes
phase in which genetic diversity is guaranteed by DNA replication and crossing over
Define differentiation phase
no further cell divisions
marked by transformation from spermatid to spermatozoa
- from spherical shaped to having head, midpiece, and flagellum
Meiosis and differentiation take place in the ________ compartment.
adluminal
1 spermatogonia divide into ______ spermatids
256 (some degenerate during the process)
Each generation of cells is attached by ________. Thus, each generation divides synchronously in cohorts.
intracellular cytoplasmic bridges
List the 4 phases in the differentiation phase
Golgi phase
cap phase
acrosomal phase
maturation phase
Define Golgi phase
acrosomic vesicle formation
a newly formed, spherical spermatid has a well developed golgi apparatus.
the Golgi vesicles fuse creating pro-acrosomic granules.
the vesicle fusion continues until a large acrosomic vesicle is formed.
- 1st part differentiation phase
Define cap phase
acrosomic vesicle spreading over the nucleus
the Golgi is migrating and the acrosome is forming a distinct cap
- 2nd part of differentiation phase
Define acrosomal phase
nuclear and cytoplasmic elongation
the nucleus is beginning to elongate and the neck between the head and tail is forming
- 3rd part of differentiation phase
Define maturation phase
final assembly that forms a spermatozoon
mitochondria form a spiral assembly around the flagellum that defines the midpiece
- 4th part of differentiation phase
Define parts of the sperm
Capitulum – fits into a depression in the posterior nucleus
Middle piece – gives the tail the flexibility when it becomes motile
Principal piece – makes up a majority of the tail
Terminal piece – end piece – where only the microtubules end
Sperm posses a _______, which beats in a snake-like fashion to propel the sperm forward
flagella
NOT cilia
What is spermiation?
release of spermatozoa into seminiferous tubules
Spermatozoa are [continually released / released in spurts] into the lumen of the seminiferous tubule
continuously released
T/F: If you travel down the seminiferous tubule, you would see spermatozoa in different stages of development
TRUE
What is the cycle of seminiferous epithelium?
the time it takes for progression through all stages * the time frame differs between species
Spermatogenic waves move in ________, like a corkscrew, towards the inner part of the _______. They are able to do this because they have ________ which allow communication between the developing cells.
spirals
lumen
gap junctions
For fertilization to occur, sperm and oocyte must meet up at a time when both are _______.
viable
What are factors in determining when the right time is for fertilization?
behavior (estrus)
sperm factors (viability)
oocyte factors (viability)
For the bull, buck, ram, dog, and cat, the sperm is deposited into the ______, which means it has to go through the ______ to the cervix
vagina
cervix
Define immediate transport in the fertilization process
retrograde loss
phagocytosis
entrance into cervix/uterus
- 1st part
Trace the pathway of fertilization
immediate transport (entrance into cervix/uterus)
cervix
uterus
oviduct
fertilization
Where are the “privileged pathways”?
cervix
During estrus, secretion of sulfomucins from the apical portion of the cervical mucosa produces ______
sheets of viscous mucus
What are the phases of sperm transport in the female tract
rapid phase
sustained phase
Define rapid phase
oviduct in minutes
await arrival of oocytes
+/- viable
result of muscle contraction
Define sustained phase
sperm delivered to oviducts “continually” from reservoirs
* Cervix
* Uterotubal Junction (UTJ)
extends time over which fertilization can occur
selected so that they are viable and morphologically normal
Stored sperm have [increased/decreased] binding ability
decreased
T/F: All subfertile spermatozoa attach well
FALSE - only some
Where is the spermatozoal reservoir?
oviductal isthmus
T/F: The estrus cycle probably regulates the number and motility of spermatozoa attached
TRUE
What are the barriers to fertilization?
