Uanatomy of M + F Repro : Bendiak Flashcards Preview

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Where does meiosis take place during the development of spermatozoa from spermatogonia?

Seminiferous tubules


Fxn of rete testes

region of anastomosing channels where the nonmotile spermatozoa enter and be moved to efferent ductules --> epididymus

- makes sense that it contains connective tissue with myoid cells: can contract and move sperm


How do the efferent ductules move the still immotile sperm?

They are lined by a mixture of columnar ciliated cells
(and cuboidal absorptive cells)

Each ductulus also has a band of circularly arranged SM around it to facilitate spermatozoa propulsion into the epididymus


Why are the ductuli (efferent ductules) and epididymus so structurally different?

Ductuli arise embryonically from primitive tubules that comprise the mesonephros

Epididymus arise from mesonephric (Wolffian) duct itself.


When does the vas deferens become the ejaculatory duct?

when the vas deferens meets the seminal vesicle


How do the seminiferous tubules help to propel the developing spermatozoa?

They have an outer basal lamina surrounded by myofibroblasts
- contract + propel spermatozoa


Spermatogenesis initially occurs with _____.
- What is it?
- What does it become once committed?
- Where is it found?

mitotic division of type A spermatogonia (2N)
- true stem cells that divide to totipotent progenitors
- once committed to meiosis, become type B spermatogonia

*found in outer region of tubules


How many chromosomes do primary spermatocytes have? (they form from type B spermatogonia)

4 C (chromosomes)
during cross over events during meiosis
- develop as primary spermatocyte at 3 weeks, then undergo meiosis II as secondary spermatocytes


How long do primary, secondary spermatocytes develop for?

Primary: 3 weeks

Secondary: 2 hours
(hardly ever observed)
- quickly progress to spermatids


What is special about the entire process of meiosis (in sperm development)?

during the entire process of meiosis, the cells derived from a given spermatogonium remain linked as a syncytium with a connected cytoplasmic bridge.
- Important for RNA exchange between developing haploid spermatids
(many recessive genes being exchanged)


During spermatogenesis, the interconnected cells (during meiosis) that are underdeveloped are surrounded by ____.

sertoli cells


blood testes barrier

Comprise of Sertoli cells via tight jxns.
- seal off spermatocytes

*spermatogonia at the base of the seminiferous epithelium are not contained in the barrier


What secretes androgen binding protein? What is its fxn?

Sertoli cells
- ABP binds T and sequesters high levels of testosterone (200x as [ ] as the blood)

*sertoli cells also produce inhibin that feeds back to the hypothalamus to inhibit FSH


When do spermatozoa gain motility?

En route along the epididymus
(they are not motile when leaving the testes)


OOcytes are derived from a population of ____.

primordial follicles
(primordial germ cells divide mitotically up to 5 months gestation --> stop in meiosis I)


What is the ovarian surface covered by?

Single layer of epithelial cells: germinal epithelium


What surrounds oocytes in the ovary during development?

Primordial follicle

--> become cuboidal = primary follicles

--> acquire more than 1 layer = granulosa cells

*multiple layers of granulosa cells surround large primary/secondary follicle
- theca cells surround granulosa cells


When are primary/secondary follicles stimulated to develop into large Graafian follicles (antral follicles) having fluid filled antrum?

After menarche
- granulosa cells proliferate and thecal cells enlarge --> graafian follicle

*remember the oocytes remain in prophase I around 6 mo after birth.

*also remember, the atretic follicles that form form primary follicles when Graafian (antral) follicles do not form


Atretic follicles

the left over primary follicles that do not develop to antral (Graafian) follicles


Thecal cells produce ____, which is converted to _____ by granulosa cells.




Corpus luteum

large endocrine group of cells that were remodeled from remaining granulosa and thecal cells after an OVULATORY FOLLICLE successfully releases an OOCYTE

*this occurs monthly and is driven by LH production


What controls the release of the corpus luteum?

LH production around 12 days into the cycle and is referred to as luteinization


Corpus albicans

corpus luteum degenerates into corpus albicans

- a residual body if implantation does not occur


2 fates of the corpus luteum

1. No fertilization
--> degenerates into corpus albicans

2. Fertilization/implantation --> Corpus luteum enlarges under the influence of chorionic gonadotropin --> responsible for maintenance of pregnancy

*placenta and CL are responsible for maintenance of pregnancy


What 2 structures are responsible for maintenance of pregnancy?

1. COrpus luteum
2. Placenta


Muscular make up of fallopian tube

inner circular
outer longitudinal

(IC, OL)

Inner has lots of folded mucosal surfaces that are secretory and ciliated with basal stem cells.
- estrogen stem cells


Two zones of the endometrium?
Which one is hormonally responsive and cycles monthly?