Histology Flashcards
What tissue is responsible for sperm & androgen production?
Testes
What tissue is responsible for sperm transport (4)?
- epididymis
- ductus (vas) deferens
- ejaculatory duct
- urethra
What tissue is responsible for semen production and sperm nutrient source (3)?
- seminal vesicle
- prostate gland
- bulbourethral glands
Name the 2 layers of CT surrounding the testes. What is the outermost layer derived from?
- inner dense capsule = tunica albuginea
- outermost layer = tunica vagnalis (derived from peritoneum)
Through which part of the testes do sperm leave the seminiferous tubules?
through the rate testis -> enter epididymis
What are the 2 general populations of cells found within the seminiferous tubules?
- somatic sertoli cells
- spermatogenic cells
What special layer is found in seminiferous epithelium?
peritubular myoid cells -> contract to project sperm out of seminiferous tubules
What is found in between seminiferous tubules?
interstitial cells of Leydig
Describe sertoli cells histologically
columnar cells w/ extensive processes that surround spermatogenic cells
- Hallmark: cyclops nucleus (center of cells w/ dark staining nucleolus)
What are Sertoli-Sertoli complexes? What is present here and how do you see it?
- tight junctions between sertoli cells that divides the seminiferous epithelium into basal and luminal compartments
- site of the blood-testis barrier (found by drawing a line between sertoli cell nuclei
Where are spermatogonia located and where do they undergo meiosis and spermiogenesis?
- located in the basal lamina of seminiferous tubules
- cross the Sertoli-Sertoli complex to enter luminal compartment to undergo meiosis and spermiogenesis
Why are sertoli cells called “nurse” cells?
- function in exchange of substrates/waste
- phagocytose residual bodies and spermatogenic cells that fail to differentiate
What cells produce 95% of testosterone in the male reproductive system? How do they stain?
interstitial cells of Leydig - stain with many white dots due to the androgens not staining well
Type A vs Type B spermatogonia
- Type A (true stem cells): remain in the basal lamina and undergo mitosis to create copies of itself and type B
- Type B: cells that enter the meiotic stages as primary spermatocytes after crossing into the luminal compartment
Explain the development of spermatocytes in the luminal compartment
primary spermatocyte -> secondary spermatocyte -> spermatids -> late spermatids -> spermatozoa (lose residual bodies)
What changes are involved in spermiogenesis?
- loss of residual body
- develop acrosome and tail
- nucleus reshapes from round to elongated
Describe the general structure of sperm
- head partially capped w/ acrosome
- tail subdivided into middle piece (mitochondria), principal piece, and end piece
What is the axoneme and where is it located?
where mitochondria and microtubules work together to produce motility in the tail of sperm
Describe the sperm transport pathway
straight tubules -> rete testis -> efferent ductules -> epididymal duct -> ductus (vas) deferens -> ejaculatory duct
SEVEn-UP
- seminiferous tubules
- epididymis
- vas deferens
- ejaculatory ducts
- nothing
- urethra
- penis
What type of epithelium is found in the epididymis?
pseudostratified columnar w/ long branched stereocilia
What are the 2 types of cells found in the epididymis?
- principal cells: columnar w/ stereocilia
- basal cells: undifferentiated precursors to principal cells
What occurs to sperm in the epididymis?
- mature and gain forward motility
- mature sperm stored i the terminal portion
What type of epithelium lines the vas deferens?
pseudo stratified columnar epithelia
What makes the vas deferens unique to identify histologically?
single lumen with a large muscular layer (inner and outer longitudinal; middle circular layer)
What do seminal vesicles secrete?
alkaline viscous fluid rich in fructose and prostaglandins; contributes to 75% of semen
Describe seminal vesicles histologically
highly folded pseudostratified columnar epithelium with walls of smooth muscle and an external CT capsule
What are the 3 zones of the prostate gland?
- central zone: closest to prostatic urethra
- transitional zone
- peripheral zone: where majority of glandular tissue is located
Describe some pathology of the zones of the prostate?
- 70-80% of prostate cancer occurs in the peripheral zone
- hypertrophy of prostate usually occurs in transitional/central zone
What type of epithelium lines the prostate gland?
simple columnar or pseudostratified epithelium
What is a hallmark of the prostate gland?
corpora amylacea - Ca deposits in the gland
What does the prostate produce?
zinc-rich alkaline fluid that neutralizes acidic vagina; also provides nutrients and liquefies semen
What type of epithelium lines the bulbourethral glands?
simple columnar epithelium
What is the function of the bulbourethral glands?
secrete clear, mucus-like fluid that contains sugars -> major component of preseminal fluid that lubricates the urethra and neutralizes traces of acidic urine
What is the names of the erectile tissue found in the penis?
- corpora cavernosa (x2) - enlarge and main cause of erection
- corpus spongiosum (contains urethra)
What surrounds each of the penile erectile tissues?
dense CT capsule - tunica albuginea
What are helicine arteries?
branches of the deep artery of the penis that dilate and fill with blood during an erection
What allows a male to maintain an erection?
compression and restriction of venous outflow while dilating the helicine arteries w/ blood
What type of epithelium lines the ovaries?
ovarian surface epithelium (OSE) -> simple squamous to low cuboidal
What 2 regions is the ovary divided into
- cortex: follicles w/ primary oocytes
- medulla: interstitial cells, neurovasculature and lymphatics
What are the 3 general phases of folliculogenesis?
- follicular phase: changes size of follicle
- ovulatory phase
- luteal phase
What makes up a follicle?
single oocyte contained within a layer of follicle cells
Define granulosa cells
follicular cells that proliferate and become stratified during folliculogenesis
What surrounds primordial follicles?
simple squamous layer of granulosa cells
What histological change is noted between primordial follicles and primary follicles?
- single layer of squamous granulosa cells becomes simple cuboidal
- zona pellucida begins to develop (separates oocyte from granulosa cells)
What is the zone pellucida?
coat of glycoproteins that encases primary oocyte
How do stromal change histologically in secondary follicles?
become stratified cuboidal epithelium and theca begins to organize
Specify between theca interna and theca externa
- theca interna: vascularized next to basal lamina; steroid producing (estradiol)
- theca externa: fibroblasts and smooth muscle continuous w/ ovarian stroma
What is the hallmark for a true secondary follicle?
- Call-exner bodies: small intercellular spaces between granulosa cells
- develop into an antrum: true cavity within the cell that contains follicular fluid (stains white)
Where does follicular fluid come from?
derived from blood vessels of theca interna
What is the hallmark of a mature follicle?
- antrum takes up majority of follicular space
- development of cumulus oophorous, mural granulosa cell and corona radiata
Define each of the following: cumulus oophorous, mural granulosa cell and corona radiata
- cumulus oophorus: keep oocyte attached to the follicle
- mura granulosa cells: line the wall of the follicle (secrete estrogen)
- corona radiata: sit directly on top of the oocyte (like a crown)
Describe histologically how the oocyte leaves the ovary during the ovulatory phase
bulge on surface of ovary forms and proteolytic activity of theca externa and tunica albuginea (create opening)
What happens to the oocyte during the ovulatory phase and what causes it?
completes meiosis I and enters meiosis II due to LH surge
How is the stigma repaired after ovulation?
mural granulosa cells and theca interna repair OSE damage
Describe the changes that occur during the luteinization part of the luteal phase
- breakdown follicle basal lamina
- blood vessels invade antrum and blood coagulates (corpus hemorrhagicum)
- mural granulosa cells - granulosa lutein cells
- theca interna -> theca lutein cells
What differentiates to produce the corpus luteum? What is the purpose of the corpus luteum?
- mural granulosa cells
- promotes endometrial changes to support implantation (through large amounts of progesterone)
What do granulosa lutein cells secrete?
progesterone and estrogen (stimulated by FSH/LH)
What do theca lutein cells secrete?
produce androstenedione and progesterone (stimulated by LH)
What 2 possilbity are there for the corpus luteum?
- fertilization: continues to enlarge and produce hormones
- no fertilization: involution stage about 14 days after ovulation (luteolysis) - does not involve atresia
What is the corpus albicans?
remnant scar tissue of corpus luteum
What is follicular atresia?
failure of follicle to ovulate (can occur at any stage of development) - follicles degenerate (apoptosis) and form atretic follicles
Describe atretic follicles histologically
glassy looking appearance that looks folded on itself with some space around follicular boundary
Which part of the oviduct has the greatest number of mucosal folds?
greatest in the ampulla
Name the 4 regions of the oviduct
- proximal infundibulum w/fimbriae
- ampulla
- isthmus
- intramural portion that opens into uterus
Describe the mucosal wall of the oviduct histologically
- simple columnar epithelium
- lamina propria
- ciliated cells
- noncilliacted secretory cells (peg cells)
Describe the development of the ciliated cells of oviduct
- enlarge and grow with increased estrogen (follicular genesis)
- lose cilia and decrease in height with increased progesterone (luteolysis)
What is the function of the noncilliated secretory (peg) cells of oviduct?
secrete nutrients for egg during migration (increased secretion w/ high amounts of estrogen)
What are the 2 layers of the endometrium?
- functional layer: lost during mensuration
- basal layer: retained during menstruation
What is the function of the muscular wall and cilia of the oviduct together?
peristaltic contraction propels the oocyte/zygote towards the uterus
What vessels supply the endometrium?
- arcuate As. - divided into 2:
- straight segment: supplies basal layer (never lost)
- coiled segment: supplies functional layer (stretches w/ endometrial growth)
What occurs to coiled segments of arcuate As. before menstration?
contraction of A. at junction between coiled-straight segments -> reduced blood flow -> destruction of functional layer
What occurs during the proliferative phase of the menstrual cycle histologically?
- uterine glands proliferating
- spiral As. elongate
The proliferative phase of the menstrual cycle is dependent on what?
estrogen
What occurs during the ischemic phase of the menstrual cycle histologically?
- regression of corpus luteum
- reduction of blood supply (ischemia)
- necrosis of functional layer
What occurs during the menstrual phase of the menstrual cycle histologically?
- functional layer sloughed away
- numerous RBCs and leukocytes
- basal layer remains
Describe the days of each of the following menstrual cycle phases: proliferative, secretory, ischemic, menstrual
- proliferative: days 5-14
- secretory: days 15-28
- ischemic: about day 1
- menstrual: days 1-4
Describe the days of each of the following menstrual cycle phases: proliferative, secretory, ischemic, menstrual
- proliferative: days 5-14
- secretory: days 15-28
- ischemic: about day 1
- menstrual: days 1-4
The secretory phase of the menstrual cycle is dependent on what?
estrogen and progesterone
How do you determine the basal layer of the endometrium historically?
right next to the myometrium
During which phase is implantation most likely to occur?
secretory phase (day 15-28) - endometrium at max thickness
Describe a decidual reaction and what is in response to?
- in response to increased progesterone (after fertilization)
- cells in lamina propria become decidual cells
What is the function of the decidual cells?
- store lipids and glycoproteins
- provides immune-protective environment
- moderates invasion of embryo from going to far
What are the 2 zones of the cervix and describe them histologically? What is in between them?
- endocervix: folded mucosa w/ deep crypts (mucus secreting); simple columnar
- ectocervix: stratified squamous epithelium (stratified prevents invasion of outside pathogens)
- transition zone: abrupt change between endocervix and ectocervix
What is a hallmark of the endocervix?
nabothian cysts
What are the 3 layers of the vagina?
- mucosal layer: nonkeritinized stratified squamous
- muscularis layer
- adventitial layer
Hallmark of the vaginal epithelium?
no glands
Describe the cyclical changes that occur in the vagina histologically
- ovulation (estrogen): stratified epithelium fully differentiated (acidophils seen)
- after ovulation (progesterone): squamous cells decrease (basophils increase)
What occurs during the secretory phase of the menstrual cycle histologically?
- glands are convoluted
- endometrium reaches max thickness
- spiral As. continue to grow
What can likely occur in the transition zone of the cervix due to disorganized epithelial cells sloughing off before reaching maturity?
dysplasia and carcinoma
Which HPV strains are high risk for cervical cancer?
HPV-16 and HPV-18
What is the standard procedure for detecting cervical pathology?
pap smear
What 3 stains are used in a pap smear?
- eosin: superficial squamous cells stain pink/orange
- light green: stains cytoplasm of less differentiated cells close to basal lamina
- hematoxylin: stains nuclei dark blue/purple
What is seen histologically in the labia majora?
pigmented skin w/ hair follicles and glands (apocrine and sebaceous)
