Flashcards in Histology: Male Reproductive System Deck (45):
What are the reproductive ducts of the male reproductive system?
Epididymis, vas deferens, ejaculatory duct and urethra
What are the accessory glands of the male reproductive system?
Seminal vesicles, prostate gland and bulbourethral glands
What are the supporting structures of the male reproductive system?
Scrotum, penis and spermatic cords
What are the testes surrounded by?
Part of the peritoneal serosa which allows testis to move freely in the scrotum
What is the tunica vaginalis?
Visceral aspect of the peritoneal serosa
What is the tunica albuginea?
A fibrocollagenous capsule which protects the testes and divides the body of the testes into lobules via septa
What are the rete testis?
Channels of ducts within the testes
Where are spermatozoa produced?
In germinal epithelia of seminiferous tubules
Outline spermatozoa transport in the testis
seminiferous tubule --> rete testis --> efferent ductules --> epidydimis --> vas deferens
Outline the order of the testes layers from outermost to innermost
tunica vaginalis (parietal layer) --> serous potential space --> tunica vaginalis (visceral layer) --> tunica albuginea --> testicular lobules
What is the function of the testis?
Spermatogenesis (and spermiogenesis) and secretion of male sex hormones (mainly testosterone)
What is present at the germinal epithelium of the testes before puberty?
Spermatogonia and Sertoli cells
What happens to the germinal epithelium at puberty?
increased testosterone production --> growth of testes --> maturation of seminiferous tubules, gamete production and development of secondary sex traits
Where are Sertoli cells located?
Cells rest on the basement membrane of the seminiferous tubule and completely enclose and support the spermatogenic cells
What is the role of Sertoli cells?
Secrete regulatory factors for: spermatogenesis & spermiogenesis, Leydig cell function, secretion of tubular fluid and phagocytosis of discarded spermatid cytoplasm
Outline the mechanism of action of Sertoli cells
Stimulated by FSH --> secrete ABP --> transports testosterone to lumen of seminiferous tubule --> spermatogenesis
ALSO: secrete inhibin --> regulates pituitary hormone production (LH and FSH)
What forms the blood-testis barrier?
Tight junction complexes between Sertoli cells; isolating the antigenically distinct gametes from the immune system
Describe the histological structure of Sertoli cells
Oval or triangular nuclei, dispersed chromatin and obvious nucleoli
Outline the process of spermatogenesis
Spermatogonia type A --> mitosis --> spermatogonia type B --> mitosis --> primary spermatocytes --> migrate to adluminal compartment --> 1st meiotic division --> secondary spermatocytes --> 2nd meiotic division --> spermatids --> spermiogenesis --> spermatozoa
Golgi app. makes large vesicle (hydrolytic enzymes) --> attaches to one pole of elongating nucleus --> forms acrosomal head cap (to digest ovum) --> centrioles migrate to opposite end and elongates to form axoneme in centre of flagellum --> 9 fibrils surround elongating flagellum --> cytoplasm migrates around around first part of flagellum (mitochondria concentrate here) in the midpiece --> excess cytoplasm is phagocytosed by Sertoli cells before spermatozoa released into lumen --> sperm won't develop motility until maturation in the epididymis
What is spermiogenesis
Conversion of spermatid to spermatozoa
When will a spermatozoa gain motility?
After maturation in the epididymis
Name the different parts of the spermatozoa
Acrosome, sperm head, cell membrane, nucleus, mitochondria, centriole, axoneme, midpiece, tail and end-piece
What is the function of the epididymis?
Accumulation, storage and maturation of spermatozoa
Describe the gross anatomy of the epididymis
Has a head, body and tail region. The head and body have smooth muscle surrounding the tube to produce slow, rhythmic motion to move spermatozoa to vas deferens
Describe the histological structure of the epididymis
A muscular tube lined by pseudostratified columnar epithelia with long microvilli (stereocilia)
What is the role of stereocilia in the epididymis?
Absorb excess fluid that accompanies the spermatozoa from the testes
How is the tail portion of the epididymis affected by the sympathetic nervous system?
Sympathetic nervous system produces strong contractions during ejaculation in the tail region of the epididymis
What is the function of the vas deferens?
Transport of spermatozoa from the epididymis to the urethra
What is the histological structure of the vas deferens?
Folded mucosa with pseudostratified epithelia, lamina propria, thick muscular wall and surrounded by adventitia (relatively loose fibrocollagenous CT)
What type of epithelia is present in the epididymis and vas deferens?
Pseudostratified columnar epithelia
Why does the vas deferens have a folded mucosa?
Allows expansion in ejaculation when sympathetic NS causes strong peristaltic contractions
What is the function of the accessory reproductive gland?
Secretions make up seminal fluid
What is the role of the seminal vesicles in the function of the accessory reproductive gland?
Produces secretion rich in fructose, vitamin C and prostaglandins
What is the role of the prostate gland in the function of the accessory reproductive gland?
Produces thin, milky secretion that is rich in citric acid and hydrolytic enzymes such as fibrinolysin which work to liquefy coagulated semen after deposition in female reproductive tract to aid fertilisation
Describe the histological structure of the seminal vesicle
Has muscular wall, highly irregular folded lining epithelia
How do the seminal vesicles react to sympathetic innervation?
Causes the contraction of the gland, propelling the secretions into the ejaculatory duct soon after the vas deferens has emptied the spermatozoa there
Describe the histological structure of the prostate gland
Fibromuscular structure that cosist of tubuloalveolar gland that surround the bladder neck and first part of the urethra, surrounded by thin fibrocollagenous capsule
Name the different zones of the prostate gland
Central zone, transitional zone and peripheral zone
Describe the central zone of the prostate gland
The part of the prostate around the ejaculatory ducts
Describe the transitional zone of the prostate gland
The part of the prostate that surrounds the first part of the urethra (prostatic urethra)
Describe the peripheral zone of the prostate gland
Where the prostate lies with the majority of glands
What is the function of the male bulbourethral glands?
Make mucous-like product which lubricates penile urethra in arousal (pre-cum)
What type of epithelia lines most of the urinary tract?
Urothelium (transitional cell epithelium), which can distend if required