Reproductive System
Male
Testes
The testes is the site of spermato- and spermiogenesis. The testes is surrounded by the tunica albuginea (TA) capsule, with lobules of coiled seminiferous tubules that will meet up at the rete testes.
TA
Blood vessel
seminiferous Tubules
L
SC
The testes has a few things to note
The Intersititial / Leydig (L) cells are found in the interstitial space between seminiferous tubules. These cells produce testosterone in response to Luteinizing hormone.
The Seminiferous tubules consist of Sertoli cels (SC) and developing sperm cells. The Sertoli cells are non dividing supporting cells, that are columnar or pyramidal in shape. The developing spermatids are in contact with the Sertoli cells, relying on them for nourishment and to coordinate maturation of the sperm cells. Once reaching the final stage of maturation the Sertoli cell will phagocytize the excess cytoplasm and cellular elements and recycle them. The Sertoli cells also secrete androgen binding protein.
The blood testes barrier (BTB) is an important element of the seminiferous tubules. It protects the developing sperm from toxins and drugs that are inside the body. It is composed of the basement membrane of the seminiferous tubule, the Sertoli cells tight junctions, and the endothelium of the blood vessel.
Spermatocyte layer, can see the condensed chromatin
Spermatids
3 year old testes
35 year old testes
15 year old testes
70 year old testes
Thesperm from every seminiferous tubule in the testes join together at the rete testes. This is lined with simple cuboidal epithelium, some having microvilli
Rete Testis
CT
Lumen
Cuboidal cells
Epididymus
The epididymus has a pseudostratified epithelia with stereo cilia. This is a site of sperm storage and maturation in the testes.
Stereolia
Vas Deferens
Nuclei of tall cells
This tube is lined with Pseudostratified columnar epithelia with stereo cilia. This tube brings sperm from the epididymus through the other glands to the urethra.
Thick muscular layer
LP
Sperm
Supporting cells
Taller columnar cells
Stereocilia
Lumen
CT capsule
Accessory Glands
The first gland that the vas deferent passes through is the Seminal Vesicle. It is highly folded and branched, with a thin lamina propria and smooth muscle layer. It is lined generally with pseudo stratified epithelia. This gland produces a yellowish, viscous component of semen rich in fructose.
Pseudostratified
LP
The Prostate is a compound tubuloalveloar or tubulosaccular gland that surrounds the urethra. The epithelia ranges from low cuboidal to squamous to simple pseudo stratified columnar. This gland secretes a slightly acidic portion of semen rich in carbohydrate, lipid and citric acid.
Comparing young and old prostate you can see the accumulation of Corpora Amylacea (CA) (calcified glycoproteins) in older prostate.
Young prostate, note no accumulations and the lumens are not expanded.
CA
Connective Tissue
The older prostate, note the expanded lumens and the accumulations.
Epithelia of gland
Penis and Urethra
The penis is made of erectile tissue called the corpora cavernosa (2 major sections in the penis) and corpus spongiosum (surrounds the urethra). These corpora are made of non fenestrated blood vessels, and is surrounded by a thick CT sheath. During an erection the blood will collect in the corpora.
The urethra lining is transitional epithelia that changes to stratified squamous at the tip.
The integument of the penis is highly innervated and can see Pacinian and Meissners corpuscles.
Lumen of urethra
Transitional Epithelia
Corpus Spongiosum
Female Reproductive System
Ovary
Germ cells
Tunica Albuginea
The entire ovary is covered by a sheet of squamous or cuboidal epithelium (germinal epithelium) which rests on a layer of dense irregular CT (tunica albuginea)
Medulla
Cortex (stroma)
The ovary is composed of a cortex and medulla region. The Cortex is composed of the germ cells in various stages of maturation. The medullar region is composed of loose CT and rich vascular supply.
GV
GC
Oocyte
TI
Many layers
Ovarian follicles have several stages of growth
Primordial follicles - An oocyte surrounded by a single layer of granulose cells (GC) that are squamous in shape. The oocyte has a prominent germinal vesicle (GV) (nuclei)
Primary Unilaminar - The granulose cells have a cuboidal shape now and are still in a single layer. The Theca Interna (TI) and the theca externa (TE) cells.
Primary Multilaminar - The granulose cells have multiplied and now create many layers of cuboidal cells surrounding the oocyte.
Secondary (Antral) - the Antrum begins to form which fills with antral fluid (liquor folliculi). Small pockets of fluid form with granulose cells that will stay in contact with the oocyte.
Graafian follicle - Has a large Antrum (A) filled with antral fluid, the corona radiata (C) is the granulose cells that surround the oocyte and separate it from the Antrum. The cells that connect the oocyte to the follicle granulose cells is called the cumulus oorphus (CO). The Graafian follicle pictured here is small compared to the size that these follicles grow to up to ovulation, with a much larger antral space.
The granulose cells form the follicle for the oocyte, these cells will secrete estradiol. These cells have abundant RER until ovulation when they turn into luteal cells with abundant SER for progesterone secretion.
The Theca Interna cells will signal to granulose cells with Androstenedione.
A
C
CO
The Graafian follicle will expel its oocyte during ovulation. The leftover follicle will develop into the corpus luteum These cells serve a temporary endocrine function to produce high levels of progesterone and estradiol, this will be maintained in pregnancy by hCG produced by developing embryo (preventing further ovulation). The granulose cells that occupied the follicle turn into luteal cells which will secrete progesterone.
If there is no fertilization and no hCG produced the corpus lute will degrade into a scar called a corpus albicans. This contains type I collagen laid down by fibroblasts.
Oviduct
The oviduct opens to the ovary and receives the oocyte after ovulation occurs. There are three sections to the oviduct; the Infundibulum, the Ampulla, and the isthmus.
The oviduct has 3 major tissue layers;
1) Mucosa
- simple columnar epithelia (tallest in ampulla), two cell types here: Ciliated (Frimbria and ampulla), Non Ciliated (peg cells, secretory in function).
-Lamina Propria
2) Muscularis
- Inner circular and outer longitudinal smooth muscle layers
3) Serosa
Peg cells
Ciliated Cells
Lamina Propria
Serosa
Mucosa
Muscularis
The Infundibulum is open to the abdominal cavity immediately beside the ovary, where the outer margins of the funnel shaped infundibulum taper to form finger like fimbria
The Ampulla is expanded region with numerous elaborate folds of mucosa (iglia)
The Isthmus is not as branched with shorter folia
Uterus
major regions of the uterus include the funds, corpus, isthmus, and cervix.
There are different layers to the uterus; Endometrium : mucosa (simple columnar epithelium with short microvilli and secretory cells) and the stromal submucosa (well vascularized CT)
there are two portions to the endometrium,
Pars Basalis - has the basal arteries and is not slugged off during menstruation
Pars Functionalis - is sloughed off, has spiral arteries. This area will vary with the menstruation cycle.
Myometrium : several layers of smooth muscle, oxytocin increases contractility.
Serosa : also called Perimetrium, loose connective tissue lined by simple squamous epithelia.
Proliferative Phase
Lumen
Epithelia
Tubular glands
The functional stages of the Uterus include
1) Proliferative (day 5-14)
at the end of menstrual flow, we see a 2-3x increase in thickness with an increase in number and length of tubular glands, coiled arteries elongate with an increase in estrogen levels.
2) Secretory / Luteal phase (day 15-18)
Further elongation of arteries, Intrauterine glands increase in activity (lumens enlarge), thickening of the endometrium due to edema and an increase in progesterone levels.
3) Menstrual phase (day 1-4)
Coiled arteries constrict, glands stop secreting, stratum functionalism sloughed off as it becomes ischemic.
Secretory Phase
Enlarged lumen
Menstrual Phase
Tissue becomes ischemic
Glands stop secreting therefore lumens collapse
Vagina
Mucosa
Adentitia
Artery
Muscularis
The vagina has 3 main layers,
1)Mucosa - Stratified squamous epithelia (superficial cells contain keratohylin granules, but undergo little keratinization). There are tight junctions between the cells.
** Epithelia is affected by ovarian hormones. Estrogen increases epithelial glycogen content, causing bacterial fauna to secrete lactic acid which lowers pH.
Lamina propria is rich in elastic fibres, lymphocytes, neutrophils. It has no glands and almost no nerve endings.
2) Muscularis - Circular and longitudinal muscle, it has striated fibres around the ostium
3) Adventitia - Dense irregular connective tissue with numerous venous plexus nerve bundles.