hormone
Does the male endocrine system have a surge center?
No!
Mitosis vs meiosis
one cell makes two vs one cell makes four
What is Spermatogonia
most primitive and present during proliferative phase, diploid, located at the basement compartment, have three types (A,I,B)
What phases are included in the differentiation phase?
Golgi, Cap, Acrosomal, maturation, condensing, acrosome formed, capability of motility
What does the proximal centriole do
gives rise to implantation apparatus, allowing for flagellum to be anchored to the nucleus
What requirements are needed for the male endocrine system
- adequate GnRH
- FSH and LH form the anterior pituitary
- Steroid hormones from the testes
Goals of spermatogenesis
continual supply of gametes, genetic diversity, maximize repro efficiency, provide immunologically protect site for process
What happens during the proliferation phase
mitotic division (diploid), creates large number of B spermatogonia
What happens during the golgi phase?
intracellular packaging occurs in al secretory cells, first development of proacrosomic vesicles form and fuse developing the acrosomic vesciel containing granules that continue to increase in size, Proximal centriole and distal centriole
What does the distal centriole do
gives rise to developing axoneme, continues phases of flagellum
When does the constant tonic/pulse secretion of LH occur in males?
can happen 4 to 8 times per 24 hours, lasting about 10 minutes
Where does spermatogenesis occur?
seminiferous epithelium or tubules
What happens during the Meiotic phase
creation of primary and secondary spermatocytes from DNA replication and crossing over ending with haploid spermatid, longest stage
What happens during the Cap phase?
acrosome forms a distinct cap over the anterior portion of the nucleus, golgi now packages the acrosomal contents and membranes causing it to move away from the nucleus eventually disappears, primitive flagellum formed and begins to project toward lumen
What is the manchette
unique system of microtubules, sometimes forming the postnuclear cap
What does constant tonic secretion of LH do in males?
constant inhibin production helps with longer half life of FSH, having a maintain level
Why is a immunological protective site needed?
sperm is a half set of DNA, the bodies immune system reacts against them
What happens during the Differentiation phase
commonly named spermiogenesis, transformation from spherical undifferentiated spermatid to highly specialized spermatozoon, same number just formation change
What happens during the acrosomal phase?
acrosome continues to spread covering about 2/3 of anterior nucleus, nucleus starts to elongate, manchette begins to develop, the spermatid become deeply embedded in sertoli cells
What does crossing over ensure
genetic diversity at the prophase 2 stage of meiosis
when is production of spermatozoa not continuous and uniform?
seasonal breeders, melatonins effect on LH and testosterone
What do sertoli cells do?
Bonus: what negative feedback occurs
convert testosterone to estrogens
Bonus: they produce inhibin which feedback to the hypothalamus and controls FSH secretion
What happens during the The very beginning of spermatozoa production
most immature germ cells located at the periphery of the seminiferous tubules move towards the lumen, developing germ cells are connected by intercellular bridges, entire cohorts are connected through the spermatid stage
What happens during the maturation phase?
portion of the manchette migrates towards tail, mitochondria migrate and cluster around the flagellum, fibrous sheath produced, dense outer fibers of the flagellum form, and final assembly is complete
How long is the prophase in bulls
19 days of the 61 day process