11. Male Histology Flashcards
What connective tissue surrounds the testis?
There is a tough connective tissue called Tunica Albuginea (the same one that surrounds the ovary) the thick connective tissue has internal accenting that run into the testes that divide it into 250 compartments. Within each of the spaces are semiferous tubules. (makes spermatozoa). Connected to a system of smaller duct which ultimately connects to the epididymis
What connects the seminiferous tubules within the testis to epididymis?
rete testis
Describe the structure of the seminiferous tubule
- Each lobule contains 1-4 highly convoluted seminiferous tubules (~50cm)
- Stratified epithelium
- Tunica (lamina) propria lacks fibroblasts but contain myoid cells
- Tunica propria also contains leydig cells (large steroid secreting cells)
Microscopic image of testes
The white lines across the testes are extensions of tunia albugenia.
The purple masses are made up of coiled seminiferous tubules.
Thin rim of myoid cells around semineferous tubule
What is the function of the sminiferous tubules?
- Stratified epithelium is site of spermatogenesis
- Spermatogonia are stem cells that divide to produce spermatocytes that undergo meiosis and mature as sperm
-
Sertoli cells are support cells for this process
- Anchor developing spermatids to the myoid cells has little arms that extend to the sperm to hold them
What is the function of the tunica propria in the seminiferous tubule?
Tunica propria, using myoid cells contract to move sperm into the epidedymis.
Epithelium from sertoli cells produce fluid to push the sperm.
What is the funtion of the leydig cells?
- Produce testosterone
- Active for the first 5 months of fetal life and then inactive until puberty
What is the tubuli recti?
It is the final and straight part of the seminiferous tubule and lines with Sertoli cells only and finally simple cuboidal epithelium.
Tubuli recti connect to the rete testis an interconnected set of channels lined with ciliated cuboidal cells
What is the epidedymis and ductus defferens derived from?
The mesonephric (Wolffian duct)
Around 20 surviving mesonephric tubules (efferent ductules) connect rete testis to single coiled ductus epididymis
What is the structure of the epididymis/efferent ductules?
- Lined with ciliated pseudostratified columnar epitheium
- Epithelium surrounded by smooth muscle
- 4-6m long and highly coiled
- Consists of head body tail
What happens in the epididymis?
- Sperm matures
- Decapitation –> inhibition of sperm to fertilise an egg
- Inhibitory factors secreted by epididymis
- Epididymis also absorbs most testicular fluid around sperm and clean up debris
- inhibition won’t be reversed until sperm reaches the vagina
Describe the structure of the Ductus deferens
- Also called vas deferens
- Runs into abdomen via inguinal canal
- Over lip of pelvis and descends to prostate at the base of bladder
- Through prostate as ejaculatory duct
- Lined with ciliated pseudostratified columnar epihtlium (same as epididymis)
- Thick smooth muscle coat (except in ejaculatory duct)
What is the function of the seminal vesicles?
- Secrete fructose, PG, and alkaline fluid to suport sperm
- PG is an active signaling moleule to modify the behvior of spermatozoa and on the smooth muslce of the vagina.
50% of volume of semen
* Has thin smooth muscle
How is the structure of the prostate arranged?
Internally divided into lobules by connective tissue
U is not a smooth tube, has a lot of sinuses opening up to it. Extends away into the surrounding tissue.
Prostatic secretion join into the urethra via this route
2 Ejaculatory ducts (extension of Vas Deferens once it enters the Prostate) beneath the urethra.
The massive tissue is prostate gland, and can be divided into
- Main prostatic glands= Glands on the outside of the prostate drains secretion into urethra that runs down and posteriorly before they converge in the midline to join the urethra.
(Submucosal glands)= Glands that have direct access to urethra
Structure of male reproductive organ
What are the zones of the prostate?
- Central zone = Surrounds ejaculatory duct
- Peripheral zone = Surrounds central zone
- Transitional zone == Surrounds prostatic urethra
- Periurethral zone = Immidiately adjacent to urethra
Prostatic histology
What are prostatic concretions?
Accumulations of protein, calcium phospahte, cholesterol and cellular debris more common with age
What is the function of the prostate?
- Produce a complex secretion
- Contain acid phosphatase, fibrolysin and coagulating factors
- Initially causes the ejaculate to clot (immobilising it) but then fibrolysin dissolves clot and frees sperm to move
- pH is close to neutrality and does not contribute significantly to alkalising vagina (role of seminal vesicles)
Penile anatomy
Three masses of cavernous tissue
- Corpora cavernosa x2
- Corpus spongiosum x1
surrounded by tunica albuginea
Penile histology
Describe the physiology of erection
- Parasympathetic stimulation relaxes cavernosal smooth muscle and dilated arteries supplying blood (Ach and NO)
- Swelling of the cavernous bodies compresses veins in superficial penis, restricting outflow
- Detumescence by sympathetic stimulation restricting inflow and contracting cavernosal smooth muscle
clitoris anatomy
Body splits, branches go back on inferior pubis bone.
Erectile tissue is unique. Because there are huge masses of erectile tissue deep to labia minor called the bulbs of the clitoris.
Clitoral histology
Clitoral erection assumed to be same basis as penile erection
should be affected by same drugs
role of the bulbs of the clitoris uncertain no male homologus
