histology of male Flashcards
Organs of the male repro system
Organs of the male reproductive system, a testis (male sex gland), a duct system, accessory glands, penis and scrotal sac
Functions- produce and store male gametes, produce the male sex hormones (androgens), deliver the male gametes to the female reproductive tract
coverings of testes
From out to in- tunica vaginalis (serous couvering), tunica albuginea (collagenous CT capsule), Tunica vasculosa (vascular capsule)
Testiculr structure
mediastinum testis (derived from tunica albuginea, subdivides each testis into 250 lobuli testis) Each lobule contains 1-4 blindly ending seminiferous tubules surrounded by a CT stroma
600-800 seminfeours tubules in a testes
Seminferous tubules
each seminferous tubule is surrounded by Leydeg cells in the interstitial area, they produce testosterone in response to LH (aka interstital stimulating hormone)
Theres a basement membrane with meyloid cells- smooth muscle cells that help move spermatazoa thru the duct
Sertoli cells make up the bulk of the seminferous tubule, theyre circular cells
Typa A and B spermatagonia, 1 the
seminiferous epithelium- spermatogenesis, sertoli cells
takes 64 days
initiated or turned on during puberty, continuously renewing process that can be subdivided into 3 phases, Spermatocytogenesis (spermatogonial phase, is the time that spermatogonia divide by mitosis and maintain a stem cell population), the process of meiosis occupies the second or spermatocyte phase. by 2 divisions primary spermatocytes become spermatids. the 3rd phase is speriogenesis/spermatid round spermatids become mature sperm
Spermatogenesis phases
Spermatogonia give rise to spermatozoa via 3 phases (name get shorter as you go down, Atocyto, atido, io)
1. Spermatocytogenesis (mitosis)- spermatogonia divide to maintain a stem cell population and to provide a pool of undifferentiated cells committed to meiosis
2. Spermatidogenesis (meiosis) - primary spermatocytes become spermatids
Spermiogenesis (differentiation)- spermatids become mature sperm
spermatocytogenesis
spermatogonia- small diploid germ cells located in the seminiferous tubules. Subsequent to puberty spermatogonia become influenced by testosterone to enter the cell cycle,
Types of spermatogonia- Dark type A spermatogonia (stem cells), Pale tyep A spermatogonia (progenitor cells), type B spermatogonia (progenitor cells)
Pale type a and type B spermatogonia are connected by intracellular bridges (cell junctions)
Spermatidogenesis
The 1st meiotic division of the primary spermatocyte is followed by the 2nd meiotic division of the secondary spermatocytes that reduces the chromosome number and DNA content to haploid (rarely seen)
Spermiogenesis
spermatids discard much of their cytoplasm, remodel organelles and form flagella to become transformed into spermatozoa
Acrosomal vescile derives from golgi apparatus (from trans golci- lysosomal fusion)
Acrosomal vesicle forms acrosomal head cap on one of the poles, centrioles from flagellum opposite head cap, coarse fibrils arrange around flagellum core, cutoplasm surrouds proximal portion of flagellum, excess cytoplasm phagocytized as residual bodies
Mature spermatozoa (sperm cellS)
Head- contains the nucleus and the acrosome, tail (connecting piece connects the head with the tail, middle piece contains mito sheat, principle piece, end piece)
the release of the mature spermatozoa from the sertoli cell into the seminferous tubule lumen is called spermiation
seminferous epithelium Sertoli cells
Somatic terminally differentiated cells, also called nurse cells, support protect and nourish germinal cells
Phagocytose cytoplasmic remnants of spermatids (residual bodies) express androgen binding proteins (ABPs), secrete hormones (inhibin and a nutritive medium
Form tight junctions (>50 sealing strands)–> B testes B, divides the germinal epithelium into the basal compartment (spermatogonia and adlumninal compartment (Spermatocytes, spermatids and spermatozoa)
Tunica propria
Each seminferous tubule is surrounded by a thin layer of contractile myoid (peritubular) cells (3-5 layers) which produces waves of contraction to move immature spermatozoa out of the testes
Basement membrane separates seminferous epithelium from myoid cells
Interstitial tissue aka Leydig cells
Comprises 25-30% of the testicular volume, leydig cells secrete testosterone (5-7 mls)
Crystals of reinke are also present although their function is unknown
hormonal control of the testis
The hypothalamus releases gonadotropin releasing hormone which controls the release of Anterior pituitary hormones FSH and LH,
FSH indirectly stimulates spermatogenesis, and LH stimulates the interstial cells to produce testosterone
Testosterone triggers spermatogenesis
Testosterone inhibits hypothalamic release of GnRH and acts directly on the anterior pituitary gland and acts directy on the anterior pituitary gland to inhibit gonadotropin release
Inhibin is produced by sertoli cell released when sperm count is high
intratesticular ducts
tubuli recti- the distal end of seminferous tubules that contain only sertoli cells, they empty into the rete testis
Rete testis- lined with cuboidal epithelium that is ciliated
Extra testicular ducts
ductus efferentes, it is lined with cuboidal and columnar epithelial cells, non ciliated cells reabsorb testicular fluid whereas ciliated cells propel the immobile sperm to the ductus epididymis
a layer of smooth muscle surrouds the walls
Ductus epididymis- can be divided into head (caput), body (corpus), and tail (cauda)
It is lined with pseudostratified columnar epithelium that have sterocilia to facilitate the motility of the sperm by absorbing the fluid
Basal cells are believed to be undifferentiated precursors of the principal cells
Spermatozoa enter the caput epididymis, travel to the corpus epididymis and are stored in the cauda of the epidiymis
ductus (vas) deferens
contains pseudostratified columnar epithelium, a prominent muscular layer surrounds the epithelium, the musclular layer contains inner and outer longitudinal muscle and middle circular muscle
A layer of connective tissue surrounds the muscular layer, during ejaculation the muscle propels the sperm forward
accessory organs
ductus deeferens extends into the ampula which is lined with columnar epithelium that contains secretory granules and there is less smooth muscle within the wall, after recieving the duct of the seminal vesicle it is within the protstate gland and referred to as the ejaculatory duct which is lined with simple columnar epithelium and a thin smooth muscle coat
Urethra
it contains a mucosa lined with epithelium, the prostatic urethra is lined with transitional epithelium, membranous urthra is lined with pseudostratified epithelium, penile urethra is lined with stratified/pseudostrafied epithelium
Accessory glands
seminal vesicle, prostate and bulbourethral glands, produce seminal and lubricating fluids, all are exocrine glands, all empty into the male duct system, secretions enhance sperm transport and viability
Seminal vesicle
Mucosa is highly folded lined with pseudostratified//simple epithelium surrounded by fibroelastic tissue and smooth muscle cells
Produces seminal fluid (70% of ejaculate)- fructose, semenogelin, prostaglandins, ascorbic acid
Prostate
30-50 tubuloalveolar glands, double layer of cells: secretory and basal, subdivider into an anterior fibromuscular stroma, the transitional zone (surrounds the urethra, BPH due to hypertrophy of stroma and glands in this zone), the central zone (surrounds the ejaculatory duct) and the peripheral zone (main glands)
Produces- proteolytic enzymes, prostatic acid phosphatase, B-microseminoprotein, prostate specific antigen
Prostatic concentrations- precipitates of prostatic secretions abundant in ederly men
prostate cancer
the most common cancer in men of all races and hispanic origin populations, Accounts for more than .5 mill cancer diagnoses in men,Af am men are at a highest risk for this tyme of cancer
Most prostate cancer arises from peripheral zne, second leading causes of cancer death among white black native, and hispanic men and fourth among asiaans
Bulbourethral glands (cowpers glands)
simple columnar epithelium- capsule fibrous Ct, produces mucus containing sugar and glycosamino glycans to lube urethra
Penis
3 cylindrical cavernous bodies corpora, a pair of corpora cavernosa, and the corpus spongiosum that surrounds the urethra, ending in the glans penis
Penile skin move freely over the underlying tissues due to the loose hypodermis
Tunica albuginea surrouds each of the corpora, the corpora contain irregular vascular spaces line by endothelium
Erection
Erection of the penis follows parasympathetic stimulation, smooth muscle in the thick wall relaxes and the vascular spaces fill with blood
As the corpora distend they press against the inextensible tunica albuginea, compressing the veins so blood is less able to drain away
The corpus spongiosum has a more extensible tunica albuginea, and so becomes less distended avoiding compression of the penile urethra
