The Male Reproductive System Histology Flashcards
During migration what does the testis carry with it?
Each testis carries with it a serous sac (tunica vaginalis)
From where the tunica vaginalis is developed?
The tunica vaginalis is developed from the peritoneum
What does tunica consists of?
- Outer patietal layer linning the scrotum
2. Inner visceral layer, covering tunica albuginea on anterior and lateral sides of testis
Each testis is surrounded by what?
Each testis is surrounded by dense CT capsule (tunica albuginea)
What do we call the tunica albuginea thickens on posterior side
mediastinum testis
What divides the testis into pyramidal compartments or testicular lobules?
Septa from tunica albuginea
Septa from the tunica albuginea penetrate testes and divide it into ??
250 pyramidal compartments or testicular lobules
What does each lobule contain?
Each lobule contains sparse CT with endocrine :
intersitial cells and
1-4 highly convulates seminiferous tubules in which sperm production occurs
How each lobule is connected to rete testis?
Short striaght tubules
Maze of channels embedded in mediastinum testis
Rete testis
How the sperm moves into the eididymis from the testis
Rete testis
What do u see in the histology of testes?
- Mediastinum
- Septa
- Seminiferous tubules
What does each lobule in the testis consists of?
- Interstitial cells —> interstitial cells of leydig
2. 1-4 highly convulted seminiferous tubules in which sperm production occurs
What does the interstitial tissue consists of?
It consists of sparse CT containing
Fibroblasts
Lymphatics
Blood vessels including fenestrated capillaries
What type of cappilary we have in the interstitial tissue? And why this not another type of cappilary?
Fenestrated capillaries
To facilitate testosterone release
They are cells located in the interstitium which posses?
Large round or polygonal cells with central nuclei
Eosinophilia cytoplasm rich in small lipid droplets
Interstitial cells of leydig
What does interstitial cells of leydig produce?
They produce steroid hormone testosterone
What is the function of testosterone?
Promotes the development of the male secondary male sex characteristics
What triggers testosterone secretion?
Pituitary gonadotropin (LH) —> interstitial cell-stimulating hormone at puberty, when hypothalamus begins producing gonadotropin releasing hormone
As u mentioned previously if gonadotropin-releasing hormone is produced during puberty then in embryonic life what stimulates testosterone release?
In the late embryonic testes gonadotropin from placenta stimulates interstitial cells to synthesize testosterone needed for development of ducts and glands of male reproductive system
When the fetal interstitial cells are active?
They are very active during 3rd and 4th months of pregnancy —> then regresses and becomes quiescent cells resembling fibroblasts until puberty when they resume testosterone synthesis in response to pituitary gonadotropin
Where are sperms produced ?
In seminiferous tubules
What connected each lobule to the epididymis?
Each lobule is actually a loop linked by a very short, narrower epithelium- lined channels embedded in mediastinum testis
What is the function of rete testis?
Connect head of epididymis to about 10-20 efferent ductules
What lines the seminiferous tubules?
Seminiferous tubule is lined
Specialized stratified epithelium called germinal or spermatogenic epithelium
What is found in the basement membrane of seminiferous tubules?
Basement membrane of this epithelium is covered by fibrous CT, with an innermost layer containing flattened, smooth muscle-like my PID cells
What is the function of myoid cells?
Allow weak contractions of tubules
What does germinal epithelium consists of ?
- Sertoli cell
2. Dividing cells of spermatogenic lineage
Is a large non dividing cell, which physically and metabolically support developing sperm cell precursors
Sertoli cell
Talk about dividing cells of spermatogenic lineage?
Cells of spermatogenic lineage, comprising four or more concentric layers of cells in germinal epithelium
Develop from progenitor cells to fully formed sperm cells over a period of 10 weeks
Define spermatogenesis?
It is the first part of sperm production —> involves mainly mitosis and meiosis and is followed by spermiogensis
What is spermiogenesis?
Final differentiation process occurring in haploid male germ cells
Small cells that divide mitotically but give rise to a population that enters meiosis and are located near the basement membrane?
Prominent spermatogonia
Remains for 3 weeks in prophase of the first meitotic division during which recombination occurs?
Primary spermatocytic
Are the largest spermatogenic cells and are usually located at all levels between basement membrane and lumen?
Primary spermatocytes
Primary spermatocytes which are rare divides to form ——- which are rare because they undergo the secondary meitoticdivision almost immediately to form two haploid spermatids
Secondary spermatids
What does the final stage of sperm the process by which spermatids differentiate into spermatozoa production depends on?
Is temperature sensitive
Is there any cell division that occur in the spermiogenesis process?
No cell division occurs in spermiogenesis
Are small cells near the lumen of the seminiferous tubules?
Haploid spermatids
What does the process spermiogensis include?
- Formation of acrosome
- Condensation and elongation of the nucleus
- Development of the flagellum
- Loss of much of cytoplasm
What does spermiogenesis result in?
It result in mature spermatozoon, which is released from Sertoli cell surface into the tubules lumen
What are the stages of the spermiogenesis?
- Golgi phase
- Cap phase
- Acrosome phase
- Maturation phase
Are tall “columnar” epithelial cells that nourish spermatogenic cells and divide seminiferous tubules into two basal and albuminal compartments
Sertoli cells
With what are all spermatogenic lineage are closely associated with?
They are associated with extended surfaces of Sertoli cells and depend on them for metabolic and physical support
To what the Sertoli cells adhere?
The Sertoli cell adhere to basal lamina and their apical ends extend to the lumen
What does Sertoli cell contain?
Sertoli cell contain abundant SER
Some RER
Well developed golgi complexes
Numerous mitochondria and lysosomes
What is the shape of Sertoli cell nuclei?
It is typically ovoid or triangular
Euchromatic and have prominent nucleolus
Features that allow Sertoli cells to be distinguished from neuroepithelium cells
What is the function of Sertoli cells?
- Phagocytosis —> during spermiogensis, excess cytoplasm sheds as residual bodies is phagocytosed and digested by Sertoli cell lysosmes
No protein from sperm normally pass back across the blood-testis barrier
- Support, protection. And nutrition of the developing spermatogenic cells:
Because spermatocytes, spermatids, and developing sperm are isolated from plasma proteins and nutrients by blood- testis barrier —> they depend on Sertoli cells for production or transport into lumen of metabolites and nutritive factors such as the iron-transport protein transferrin
Protect spermatogenic cells from circulating immune components
Supply many plasma factors needed for cell growth and differentiation
- Exocrine and endocrine secretion —>
Continues release Into seminiferous tubules water that carries new sperm out of testis
Production of nutrients and androgen-binding protein (ABP)
Which concentrates testosterone to a level required for spermatogenesis —> is promoted by FSH
Secrete glycoproteins inhibin —> which feeds Bach on anterior pituitary gland to suppress FSH synthesis and release
In fetus Sertoli cells also secrete 140 KDa glycoproteins (MUllerian inhibiting substance ) that causes regression of embryonic MUllerian paramesonephric ducts; in the absence of MIS these ducts persists and become parts of female Reproductive tract
What are the intra testicular ducts?
- Straight tubules
2. Rete testis
Connect loops of seminiferous tubules to rete testis
Straight tubules
With what the striaght tubules are lined initially?
They are lined initially by by Sertoli cells
An interconnected network of channels lined with cuboidal epithelium and supported by CT of mediastinum
Rete testis
What epithelium lines the rete testis?
Lined by cuboidal epithelium and supported by CT of mediastinum
To what rete testis drains?
Rete testis drains into about 20 efferent ductules
What lines the efferent ductules that the rete testis drain to?
Unusual epithelium in which groups of non-cilliated cuboidal cells and give tissue a characteristically scalloped appearance
What is the function of the non cilliated cells that line the efferent ductules?
Non-cilliated cells absorb some fluid secreted by Sertoli cells —> this absorption and cillary activity create fluid flow that carries sperms passively out of testis toward epididymis
Does the wall of the efferent arterioles have any muscles?
Thin layered of circularly oriented smooth muscle cells in the walls of efferent ductules aids the movement of sperm into the duct of epididymis
Is the site where the spermatozoa undergoes maturation and acquire ability to fertilize
Epididymis
What are the important changes that occur in the sperm while passing in the epididymis?
- Development of competence for independent forward mortality
- Maturation of acrosome
- Biochemical and organizational changes within cell membrane
What does fluid within the epididymis contains?
glycoproteins “decapacitation factors” that bind plasma membranes of sperm and block acrosomal reactions and fertilization have ability until these factors are removed as part of capacitation process in female reproductive tract
What lines the epididymis?
Psuedostratified columnar epithelium
Consisting of columnar principal cells
With characteristic long sterocillia
And small round stem cells
Secrete glycoproteins and glycolipids but also absorb most of the remaining water and remove residual bodies or other debris not removed earlier by Sertoli cells
Principle cells
Duct epithelium is surrounded by what?
It is surrounded by few layers of smooth muscle cells arranged as inner and outer longitudinal layers
And circular layer in the tail of epididymis
