Histology of Male Reproductive System Flashcards

1
Q

What does the male reproductive system consist of?

A

Testes

System of genital ducts

Accessory genital glands

Peis

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2
Q

What do the seminiferous tubules of the testes produce and secrete?

A

Spermatozoa

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3
Q

What do the testes contain?

A

Contain endocrine cells, the interstitial cells (of Leydig) that secrete the male hormone, testosterone

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4
Q

What are the structures within the testes?

A

Tunica albuginea

Tunica vasculosa

Lobuli testis

Seminiferous tubules

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5
Q

What are the characteristics of the tunica albuginea?

A

CT capsule that encloses each testis

Composed of dense irregular collagenous CT

Mediastinum testis

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6
Q

What is the mediastinum testis?

A

Part of the tunica albuginea

Thickened portion of the tunica albuginea where the epididymis attaches

Site where blood vessels, lymphatics vessels, nerves and genital ducts come in or not

Gives rise to incomplete CT septa that radiate into testis - septa subdivide testis into about 250 lobuli testis (lobules)

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7
Q

What are the characteristics of the tunica vasculosa?

A

Layer of loose CT deep to the tunica albuginea

Has a rich vascular supply and is the vascular capsule around the testis

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8
Q

What are the characteristics of the Lobuli testis?

A

Each lobules contains:

1-4 coiled seminiferous tubules

Interstitial cells of Leydig

Loose CT stroma - highly vascularized, fills the spaces between seminiferous tissues in the lobuli testes and is also where interstitial cells of Leydig are located

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9
Q

What are the components of the Seminiferous Tubules?

A

Tunica (lamina) Propria

Basal Lamina

Seminiferous Epithelium (germinal epithelium)

Sertoli cells

Compartments of seminiferous epithelium

Spermatogenic cells

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10
Q

What are the characteristics of the tunica (lamina) propria of the seminiferous tubules?

A

Thin CT layer that contains collagen and 3-5 layers of myoid cells (contractile) that produce rhythmic contractions to move spermatozoa through the tubules

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11
Q

What are the characteristics of the seminiferous epithelium or germinal epithelium?

A

Stratified epithelium that lines interior of seminiferous tubules

Contains spermatogenic cells (gametes) and Sertoli cells (support)

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12
Q

How do the spermatogenic cells differentiate and then become sperm?

A

Undergo progressive differentiation as they move from periphery of the seminiferous tubules to the hollow lumen, where they are released

Spermatozoa pass through genital ducts to reach exterior

As sperm pass through the ducts, the accessory glands (seminal vesicles, prostate, and bulbourethral glands) release secretory products into genital duct lumen to form semen (fluid + sperm)

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13
Q

What are the Sertoli cells and their function?

A

Tall, columnar, non-replicating cells

Highly folded

Clear, ovoid or triangular nucleus and prominent nucleolus

Sertoli cell to Sertoli cell junctional complex binds the lateral cell membranes of adjacent Sertoli cells together to compartmentalize seminiferour epithelium into 2 compartments

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14
Q

What is the seminiferous epithelium compartments?

A

Luminal compartment - adluminal

Basal epithelial compartment

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15
Q

What do the occludens junctions of the Sertoli cells create?

A

Blood-testis barrier

Sertoli cells provide physical support and also physiological support for spermatogenic cells

BTB isolates the haploid secondary spermatocytes, spermatids, and spermatozoa from immune system in adult

BTB has gap junctions

Release androgen-binding protein (ABP), hormones, and nutrients

Testosterone binds to ABP in seminiferous tubules which promotes spermatogenesis

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16
Q

What is in the luminal compartment of the seminiferous epithelium?

A

Spermatozoa

Spermatids

Secondary spermatocytes

Primary spermatocytes

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17
Q

What is in the basal epithelial compartment of the seminiferous epithelium?

A

Basal to the zonulae occludentes (ZO) formed by Sertoli cells

ZO forms the BTB which segregates the luminal from the CT - it shields the forming gametes from the immune system

Contains spermatogonia and early primary spermatocytes

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18
Q

What are the spermatogenic cells?

A

Spermatids (most mature)

Secondary spermatocytes

Primary spermatocytes

Spermatogonia (least mature)

Umbilical vesicle (yolk sac) gives rise to primordial germ cells which in turn differentiate into spermatogonia

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19
Q

What is spermatogenesis?

A

Maturation process of spermatogenic cells

It begins in response to pituitary gonadotropin release shortly before puberty

Takes about 74 days for spermatogonium to transition through process of spermatogenesis

Takes approximately an additional 12 days for a sperm to pass through epididymis

3 phases - spermatogonial, meiosis, spermiogenesis

20
Q

What happens during the spermatogonial phase of spermatogenesis?

A

Occurs in basal compartment

Process by which spermatogonia differentiate into primary spermatocytes

Spermatogonia rest directly on basal lamina and have 46 single chromatid chromosomes (2n, 2d)

3 types of spermatogonia

21
Q

What are the 3 types of spermatogonia?

A

Type A dark spermatogonia

Type A pale spermatogonia

Type B spermatogonia - these undergo mitosis to form primary spermatocytes (2n, 2d)

22
Q

What occurs during the spermatocyte phase (Meiosis)?

A

Occurs in luminal compartment

Process by which primary spermatocytes differentiate into spermatids

Primary spermatocytes (2n, 4d) are largest cells of the seminiferous epithelium

Primary spermatocytes enter Meiosis I to form secondary spermatocytes that have 23 double chromatid chromosomes (1n, 2d)

Secondary spermatocytes are rarely observed because they enter Meiosis II immediately to form spermatids that have 23 single chromatid chromosomes (1n, 1d)

23
Q

What occurs during the spermatid phase (spermiogenesis)?

A

Occurs in luminal compartment

Process by which spermatids are transformed into spermatozoa (sperm)

Spermatids are very small cells with round, dense nuclei, and occurs in groups next to lumen

Spermatids are non-motile and transform into motile spermatozoa (1n, 1d)

24
Q

What are the interstitial cells of Leydig?

A

Located in the lobuli testis, in the loose CT stroma that fills the spaces between adjacent seminiferous tubules

Endocrine cells - stimulated by gonadotropins (FSH, LH) to synthesize and secrete testosterone

25
What are the genital ducts?
These are the pathway of sperm (and semen) through the genital system Spermatozoa are formed in the seminiferous epithelium lining the seminiferous tubules and then pass through genital ducts
26
What are the genital ducts in order?
Tubuli recti Rete testis Efferent ductules Duct of the epididymis Ductus deferens Ejaculatory duct Urethra
27
What are the intratesticular genital ducts?
Tubuli recti - lined by Sertoli cells and lined by simple cuboidal epithelium in the distal end Rete testes - Labrinthine spaces, lined by simple cuboidal epithelium or low columnar epithelium
28
What are the extratesticular genital ducts?
Epididymis Ductus deferens (vas deferens) Ejaculatory duct
29
What is the epididymis?
This is where sperm acquire their motility Motility likely due to changes in intracellular levels of cAMP, Ca 2+, and pH Has efferent ductules Duct of epididymis
30
What are the histological characteristics of the efferent ductules of the epididymis?
Pseudostratified columnar epithelium with cilia Basal lamina Thin loose CT Smooth muscle cells - circularly arranged Apical cell membrane invaginations resorb fluid (released by Sertoli cells) from lumen by endocytosis Cilia sweep the sperm towards the ducts of epididymis
31
What are the characteristics of the duct of epididymus?
Regions - head, body, tail Pseudostratified columnar epithelium with stereocilia Basal lamina Loose connective tissue Smooth muscle layer - peristaltic contractions
32
What are the characteristics of the ductus deferens?
Pseudostratified columnar epithelium with sterocilia Basal lamina Loose fibroelastic CT - folded Smooth muscle coat: inner layer = longitudinal, middle layer = circular, outer layer = longitudinal Ampulla - dilated end of the ductus deferens, joins the seminal vesicles to form the ejaculatory duct
33
What are the characteristics of the ejaculatory duct?
Simple columnar epithelium Basal lamina Subepithelial CT No smooth muscle
34
What are the accessory genital glands?
Seminal vesicles Prostate gland Bulbourethral glands
35
What are the characteristics of the seminal vesicles?
Epithelium is pseudostratified columnar epithelium with short round basal cells and tall non-ciliated columnar cells Subepithelial CT is fibroelastic Smooth muscle coat Thin fibrous coat covers smooth muscle coat Controlled by testosterone Function is secretion of viscous, yellow, fructose-rich seminal fluid with amino acids, ascorbic acid, prostaglandins, and proteins
36
What are the characteristics of the prostate gland?
Largest accessory gland, chestnut-shaped Capsule is dense irregular collagenous CT (highly vascular) and smooth muscle cells CT stroma arises from the capsule and is the same as the capsule Tubuloalveolar glands
37
What are the layers of the tubuloalveolar glands?
Mucosal layer - inner layer, has small glands Submucosal layer - intermediate layer, has larger glands Peripheral layer - has the main prostatic glands, the largest glands Simple to pseudostratified columnar epithelium - synthesizes proteins Prostatic concretions - corpora amylacea, calcified glycoproteins
38
What is benign prostatic hyperplasia?
Non-harmful enlargement of the prostate becomes more common with age
39
What is adenocarcinoma of the prostate?
Prostate cancer
40
What are the characteristics of the bulbourethral glands (Cowper's glands)?
Located at proximal end of the membranous urethra Capsule is fibroelastic CT, which gives rise to septa which divides the gland into lobules Compound tubuloalveolar glands are simple cuboidal to simple columnar epithelium Secretes thick, slippery fluid to lubricate lumen of urethra
41
What are the characteristics of the erectile tissue?
3 columns, each covered by a dense, fibrous, CT capsule - the tunica albuginea 2 corpora cavernosa - dorsally 1 corpus spongiosum - ventrally
42
What are the layers of the urethra?
Transitional epithelium Lamina propria - loose fibroelastic tissue, very vascular, contains glands of Littre Muscularis - layer of smooth muscle outside the mucosa. upper 2/3rds of the urethra has two layers of smooth muscle (inner longitudinal and outer circular). Lower third has three layers of smooth muscle: inner longitudinal, middle circular, outer longitudinal Adventitia
43
What are the characteristics of the prostatic urethra?
3-4 cm long, lies in the prostate gland Lined by transitional epithelium
44
What are the characteristics of the membranous urethra?
1-2 cm long Passes through the perineal membrane Lined by stratified columnar epithelium Interspersed with patches of pseudostratified columnar epithelium
45
What are the characteristics of the spongy urethra?
Passes through the length of the penis and corpus spongiosum Stratified columnar epithelium Interspersed with patches of pseudostratified columnar and stratified squamous, nonkeratinized epithelium Glans is stratified squamous epithelium
46
What are the two mucus glands of urethra?
Glands of Littre - urethral glands Bulbourethral Glands (of Cowper) Lubricate the urethral lumen Glands are located along the length of the penile urethra