L33. Male Reproductive 1 Flashcards
What are the 4 components in a male reproductive organ?
- testes
- genital ducts
- accessory genital glands
- penis
Name the endocine and exocrine functions of the testes
exocrine: spermatozoa in seminiferous tubules
endocrine: testosterone (Leydig cells)
Are the accessory genital glands endocrine or exocrine
exocrine
What is the dual function of the penis
- urinary conduct
2. semen release
Describe the histology of the testis
- dense connective tissues of the capsule and septa
a. capsule is thick/white/collaganous
b. septae divides testicular tissues into lobules - lobules contains loose connective tissue and semniferous tubules
a. loose connective tissue: contains Leydig cells (secrete testosterone)
b. semniferous tubules - lined by supportive simple columnar Sertoli cells AND germ cells embedded in epithelium
Draw the structure of the testes. Include
Vas deferens,epididymis, Rete Testis, Tunica albuginea, seminiferous tubules, testicular lobules and septum
pg 3a. L 33.
What is the tunica albuginea
It is the dense connective tissue that forms the capsule in the testes
What is a Leydig cell island
consists of a cluster of steriodogenic cells and embedded in highly VASCULARIZED loose CT
What stimulates Leydig cells to produce testosterone
Leutinizing hormones
Draw how testosterone is eventually secreted by Leydig cells due to LH.
pg 4a L 33
How do LH stimulate Leydig cells
- LH binds to the receptors on the LEydig cells
- stimulates a G-protein coupled cAMP cascade
- cAMP (messanger) activates protein kinase which activates cholesterol esterases which cleaves free cholesterol
- free cholesterol enters the mitochondria where there is a lipid transfer protein ( binds to pregnenolone) that carries the lipid to the SER
- SER makes the steroid which leaves the cell to the loose CT
- testosterone gets picked up by fenestrated capillaries and nearby Sertoli cells
What does steriodogenesis require
cholesterol/lipid based transport between the mitochondria and SER
What are the 3 developing germ cells ( name locations)
- spermatogonia (basal)
- spermatocyte (ad luminal)
- spermatotid (luminal)
Where does male germ cell development occur
basal to luminal across seminiferous epithelium
What cells are the developing germ cells in contact with?
Sertoli cells via cell-cell junctions
What is spermatogonia?
- basal stem cells ( diploid)
2. testosterone responsible for proliferation and differentiation
What are spermatocytes
- undergo meiosis to become haploid
- migrate across tight junctions of the seminiferous epithelium to the adluminal compartment ( protected from the immune system)
What are spermatids?
- they are luminel (haploid)
2. undergo morphological differentiation (spermiogenesis) to become spermatozoa
What are spermatozoa?
- haploid
- not yet motile
- released into the seminiferous tubule lumen which is filled with nutritive Sertoli cell secretions/fluids
Draw the tissue structure of the developing germ cell layers defining clearly the basal and adluminal compartment
pg 6a L 33
How do developing germ cells contact each other
cytoplasmic bridges
How do developing germ cells contact Sertoli cells
adhesive junctions
how long is the wave for germ cell development
64 days
How are the spermatogonia and spermatocytes separated
separated by an adluminal immunoprotected junction filled with tight junctions
Is the basal compartment of the lobules of the testes immunocompetent or immunrotected
immunocompetent
Describe the components to the spermatozoa
- head- contains nucleus (condensed chromatin) and acrosome ( modified lysosome)
- neck - contains centrioles (root of axoneme)
- midpiece- rich in mitochondria for ATP production
- annulus-9 outer pairs 2 central pairs:axoneme(drives flagellar motility)
- tail - flagellar for motility -axoneme and densa fibers (intermediate filaments)
Draw the spermatozoa label all compnents
pg 6b. L 33
What is the axoneme
component of the spermatozao that contains 9 outer pairs and 2 central pairs needed for flagellar motion
What are the 2 primary purposes of genital ducts
- collect/transport spermatozoa
2. collect and modify tubular/ductular fluid
What are the 2 branches of genital ducts
intratesticular ducts
extratesticular ducts
What are the 2 intratesticular ducts
- rete testis
2. ductuli efferntes
Describe the function of rete testis
- passive transport of spermatozoa(non-motile) by bulk flow of Sertoli cell secretions and myoid cell contractions
- net-like network of tubes that collect spermatozoa and move them through the tunica albuginea
- lined by simple cubodial epithelium
Describe the function of the ductuli efferentes
- weak active transport of non-motile spermatozoa
- thin layer of smooth muscle in wall (peristaltic; facilitates flow out of the seminiferous tubules/rete testis)
- simple ‘scalloped’ epithelium
a. cubodial cells: resorptive (initiate flow out of the S. tubule)- move fluid
b. columnar cells are ciliated (beat and facilitate flow out of the seminiferous tubule) - move spermatozoa
What are the 3 extratesticular ducts?
- epidiymis
- vas deferens
- ejaculatory ducts
What is the function of the epidymis
- stores the spermatozoa
- prominent circularly arranged smooth muscles in walls : initiates active ejaculatory transport of spermatozoa towards the vas deferens
- has a pseudostraified epithelium
Describe the pseudostratified epithelium layer of the epididymis
- basal stem cells
- principal cells with stereocilia (non-motile microvili to increase surface area)
- resorb excess luminal fluid
- phagocytose excess spermatozoan cytoplasm
Describe the vas deferens
- epithelium similar to epididymis
- 3 thick layers of smooth muscle
- powerful rhythmic contractions for active ejaculation of spermatozoa
- initiated by sympathetic nervous system (short lived response)
Describe the ejaculatory ducts
- similar epithelium to the epididymis
- no smooth muscle in the wall; passive flow from the vas deferens
- passes through prostate : deleivers spermatozoa and seminal fluid to the urethra below the bladder
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