Male Repro Histo Flashcards
What is the role of the male reproductive system?
- production, nourishment, and temporary storage of sperm
- synthesis and secretion of male sex hormones, androgens
What part of the male reproductive system produces sperm and androgens?
testes
What part of the male reproductive system transports sperm?
epididymis, ductus deferens, ejaculatory duct, urethra
What part of the male reproductive system produces semen and a sperm nutrient source?
seminal vesicle, prostate gland, bulbourethral gland
What part of the male reproductive system is a compulatory organ with erectile tissue?
penis
Testes
- location
- suspended by
- surrounded by
- thickens
- paired organs located in the scrotum
- posteriorly associated with the epididymis
- suspended by spermatic cord
- surrounded by dense CT capsule: tunica albuginea
- thickens posteriorly forming mediastinum testes
What is tunica albuginea?
-thick dense CT capsule surrounding the testes
Do the testes have lobules?
yes, 250-300 created by septa
What is the tunica vaginalis?
- outer parietal layer lining the scrotum
2. inner visceral layer, covering the tunica albuginea
What is the tunica vaginalis derived from?
peritoneum
How many seminiferous tubules are contained in each testicular lobule?
1-4
What do seminiferous tubules contain?
seminiferous epithelium
- somatic sertoli cells
- spermatogenic cells
What are seminiferous tubules surrounded by?
CT and 3-5 layers of peritubular myloid cells
Where are interstitial cells of Leydig cells found?
in between seminiferous tubules
What cells make up seminiferous epithelium?
stratified epithelium with sertoli cells and spermatogenic cells
What are sertoli cells?
- structure
- hallmark
LO2
columnar cells with extensive processes that surround spermatogenic cells and occupy spaces between them
- organize tubules and extend full thickness of epithelium
- Hallmark: cyclops nucleus
What are spermatogenic cells?
- replicate and differentiate into mature sperm
- spermatogonia (most immature) rest on basal lamina
- spermatids (most mature) are attached to apical portion of Sertoli cell, near tubule lumen
What is the Sertoli-Sertoli complex?
LO2
Sertoli cells bound to one another to create tight junctions (zonula occludens) that include more than 50 parallel fusion lines in the adjacent membranes
-divides teh seminferous epithelium into basal and luminal compartments
What is the blood-testis barrier?
- Sertoli to Sertoli junctional complex
- isolates haploid germ cells (secondary spermatocytes, spermatids, and sperm) from systemic circulation and immunue system
What is restricted to the basal compartment of the testes?
spermatogonia and early primary spermatocytes
What is restricted to the luminal side of testes?
mature spermatocytes and spermatids
Where do meiosis and spermiogenesis occur?
luminal compartment
What are “nurse” cells?
LO2
Sertoli cells
- function in exchange of substrates/wastes
- phagocytose residual bodies (spermiogenesis) and spermatic cells that fail to differentiate
Interstital cells of Leydig
- location
- close to
- produce
LO2
- in the intertubular space
- close to blood vessels and lymph channels
- steroid-producing cells: contain lipid droplets, mito wtih tubular cristae, and well-developed sER
- produce 95% testosterone
Type A spermatogonia
clonally divide (mitosis) -generates copies of itself and/or differentiates to Type B spermatogonia
Type B spermatogonia
- divide (mitosis) and cells immediately enter meiotic prophase as primary spermatocytes
- ensures 2x DNA when starting meiotic prophase I
Spermatocytes
- what they undergo
- where
2 meiotic divisions inside blood-testes barrier
- primary spermatocytes –> secondary spermatocytes (2)
- secondary spermatocytes –> spermatids (2)
round early spermatids
housed in niches in cytoplasm of sertoli cells
elongated late spermatids
housed in crypts, deep invaginations in sertoli apical cytoplasm
What is spermiogenesis?
last step of spermatogenesis
-develop acrosome and tail and shape of nucleus
What is spermiation?
release of mature spermatids
-intracellular bridges –> residual bodies –> lost and mature spermatids are separated
golgi phase
- hydrolytic enzymes are sorted from golgi to acrosomal vesicle
- axoneme begins to assemble
cap phase
- acrosomal sac forms cap, attached to nuclear envelope
- spermatid rotates and axoneme orients toward basal lamina
acrosomal phase
- manchette involved in protein trafficking, develops from microtubules
- axoneme extends and flagellum grows
maturation phase
- unneeded cytoplasm is shed as residual body and intercellular bridges are lost
- mature but not yet functional sperm released
sperm structure
-head and tail surrounded by plasma membrane
describe sperm head
- flattened condensed and elongated nucleus
- partially capped by acrosome covering anterior 1/2 of nucleus
- contains hydrolytic enzymes
What are parts of spermatic tail?
- middle piece
- principal piece
- end piece
Describe the middle piece of the spermatic tail
- helical mitochondrial sheath
- axoneme
- outer dense fibers surrounding the axoneme and projecting down the tail
Describe the principal piece of the spermatic tail
- longest
- central axoneme surrounded by fibrous sheath
- fibrous sheath provides scaffold during sliding/bending of tail during forward motility
Describe the end piece of the spermatic tail
very short segment of the tail that only contains the axoneme
sperm transport pathway
seminiferous tubules straight tubules rete testis efferent ductules epididymal duct ductus (vas) deferens ejaculatory duct
seminiferous tubules
- location
- epithelium
- support tissues
- function(s)
- location - testicular lobules
- epithelium - spermatogenic with sertoli cells and germ cells
- support tissues - myoid cells and loose CT
- function(s) - produce sperm
straight tubules
- location
- epithelium
- support tissues
- function(s)
- location - periphery of the mediastinum testes
- epithelium - proximal: sertoli cells only; distal: simple cuboidal
- support tissues - CT of mediastinum
- function(s) - convey sperm to rete testis
rete testis
- location
- epithelium
- support tissues
- function(s)
- location - in mediastinum of testis
- epithelium - simple cuboidal or low columnar
- support tissues - dense irregular CT, highly vascular
- function(s) - collects sperm from seminiferous tubules
efferent ductules
- location
- epithelium
- support tissues
- function(s)
- location - from rete testis to head of epididymis
- epithelium - pseudostratified columnar, some have microvili
- support tissues - fibromuscular with elastic fibers
- function(s) - convey sperm to epididymis
epididymal duct
- location
- epithelium
- support tissues
- function(s)
- location - head, body, and tail of epididymis
- epithelium - pseudostratified columnar with sterecilia
- support tissues - head, body: circular smooth m; tail: outer circular layer and inner and outer longitudinal layer of smooth m
- function(s) - sperm maturation and short term sperm storage; expels sperm at ejaculation
vas deferens
- location
- epithelium
- support tissues
- function(s)
- location - extends from epididymis to ejaculatory ducts in prostate gland
- epithelium - pseudostratified columnar with stereocilia
- support tissues - fibroelastic lamina propria, inner + middle circular + outer longitudinal layers of smooth m
- function(s) - carries sperm from epididymis to ejaculatory ducts
ejaculatory ducts
- location
- epithelium
- support tissues
- function(s)
- location - ductus deferens and ducts of the seminal vesicles; located in prostate
- epithelium - pseudostratified and simple columnar
- support tissues - fibroelastic tissue and smooth muscle
- function(s) - mix sperm and seminal fluid, deliver semen to urethra, prostatic secretion is added here
epididymis
- what is it
- lining
- cells
- added function of sperm
- storage
- highly elongated and coiled duct (6 m in adult males) where sperm mature
- lined with pseudostratified columnar with long and branched stereocilia
- principal cells - columnar cells extending from lumen to basal lamina with sterocilia/stereovili
- basal cells - associated with basal lamina, undifferentiated precursors of principal cells
- sperm maturation acquiring forward motility
- stored in terminal portion
ductus deferens
- length
- lined
- wall
- support
- 45 cm muscular tube
- pseudostratified columnar epithelia
- CT lamina propria with elastic fibers
- muscular wall with inner and outer longitudinal layers + middle circular layer
- external layer of loose CT and adipocytes
What is the ampula of ductus deferens?
dilated portion that leads directly into prostate gland
-distal end receives the ducts of the seminal vesicle forming ejaculatory ducts
What are accessory glands fo the male reproductive system?
- seminal vesicles
- prostate gland
- bulbourethral glands
- urethral glands
