Histology of the Male reproductive system

Question 1

what does sperm and androgen production in the male repro tract?

Answer 1

Testes

Question 2

what does sperm transport in the male repro tract?

Answer 2

Epididymis
Ductus deferens
Ejaculatory duct
Urethra

Question 3

What does semen production and sperm nutrient source in the male repro tract?

Answer 3

Seminal vesicle
Prostate gland
Bulbourethral glands

Question 4

what does copulatory organ with erectile tract in the male repro tract?

Answer 4

Penis

Question 5

Characteristics and components of the testes?

Answer 5

Paired organs located in the scrotum, posteriorly associated with the epididymis

Dense CT capsule, the tunica albuginea that thickens posteriorly to form the mediastinum testis

also contains the tunica vaginalis which is derived from the peritoneum

• outer parietal layer lining the scrotum
• inner visceral layer covering the tunica albuginea

Question 6

Characteristics and cell types of the seminiferous tubules

Answer 6

Septa creae 250-300 lobules containing 1-4 convoluted seminiferous tubules lined with seminiferous epithelium

• Sertoli cells
• Spermatogenic cells

Tubules surrounded by CT and 3-5 layers of peritubular myoid cells (help with contraction)

Interstitial cells of leydig found in between seminiferous tubules

Question 7

Characteristics of Intersitial cells of Leydig

Answer 7

Present in between tubules close to blood vessels and lymphatic channels

Steroid producing cells containing lipid droplets, mitochondria, and a well developed sER
-Testosterone

Accompanied by myoid cells and fibroblasts

Question 8

what two cells make up the Seminiferous epithelium and what are their characteristics

Answer 8

Sertoli cells:

• columnar cells with extensive processes that surround spermatogenic cells and occupy the spaces between them
• organize tubules and extend full thickness of epithelium
• cyclops nucleus

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

Question 9

What is the function of the sertoli cells and how do they communicate?

Answer 9

Nurse cells with crypts supporting 30-50 germ cells

Function in:

• exchange/transport of metabolites and nutritive factors into lumen
• exocrine and endocrine secretion
• phagocytose residual bodies and effete spermatogenic cells

Bound by tight junctions to form the sertoli cell to sertoli cell junctional complex and establishes the blood-testis-barrier

Question 10

two types of spermatogonia?

Answer 10

Spermatogonia: clonally divide (mitosis) located near the base ment membrane

Type A spermatogonia: generate copies of itsself and or differentiates into type B spermatogonia

Type B spermatogonia enter the meiotic prophase as primary spermatocytes

Question 11

What are spermatocytes

Answer 11

Two meiotic divisions and inside blood testes barrier

primary spermatocytes go to secondary spermatocytes and then finally to spermatids as they move towards the lumen of the seminiferous tubule

Question 12

what are the seminiferous compartments ad how do the sepermatocytes move throughout?

Answer 12

Sertoli-sertoli junctional complex divides epithelium into the basal and ad(luminal) compartments

• basal is below the blood testes barrier
• adluminal is above the blood testes barrer

Spermatogonia and early primary spermatocytes are restricted to basal compartmetn

Mature spermatocytes and spermatids are restricted to the adluminal side

Early spermatocytes must pass through junctional complex and move from basal to the adluminal compartment

complexes establish the blood testes barrier to help isolate the haploid cells from systematic circulation

• secondary spermatocytes
• spermatids
• sperm

Question 13

process of spermatogenesis in the seminiferous tubules and when is the spermatid released from the seminiferous tubules?

Answer 13

Spermatids undergo spermatogenesis

• Round spermatids (early) are housed in niches of sertoli cells
• elongated (late) spermatids: housed in apical crypts of sertoli cells

Mature spermatids are released via spermiation:

• intercellular bridges leave residual bodies and lost and mature spermatids are lost
• spermatozoa are fully formed but not yet functional
• sperm are released into lumen and propelled to the epididymal duct

Question 14

Structure of the sperm

Answer 14

Mature sperm are comprised of a head, neck, and tail

Head contains a flattened and elongated nucleus
-partially capped by the acrosome which contains hydrolytic enzymes

Tail is subdivided into 3 pieces:

• Middle piece, containing mitochondria
• principle piece: longest segment
• end piece

Question 15

What is the sperm transport pathway?

Answer 15

Straight tubules
Rete testis
Efferent ductules
Epididymis
ductus deferens
Ejaculatory duct

Question 16

Location, epithelium, support tissues and function: Seminiferous vesicle

Answer 16

Location: Testicular lobules

Epithelium: Spermatogenic, with setoli cells and germ cells

Support tissues: myoid cells and loose CT

Function: Produce sperm

Question 17

Location, epithelium, support tissues and function: Straight tubules

Answer 17

LOcation:
-Periphery of the mediastinum testis

Epithelium:

• proximal= sertoli cells only
• distal = simple cuboidal

Support tissues:
-Connective tissue

Function:
-Convey sperm into rete testis

Question 18

Location, epithelium, support tissues and function: Rete testis

Answer 18

Location:
-In mediastinum testis

Epithelium: Simple cuboidal with microvilla and single cilla

Support tissues:
-Dense irregular CT, highly vascular

Functions:
-Collects sperm from seminiferous tubules

Question 19

Location, epithelium, support tissues and function: Efferent ductules

Answer 19

Location: From rete testis to the head of the epididymis

Epithelium: Alternating patches of simple, cuboidal nonciliated and simple columnar ciliated

support tissues:
-thin circular layer of smooth muscle and vascular loose CT tissue

Functions:
-Convey sperm into the epididymis

Question 20

Location, epithelium, support tissues and function: Epididymal duct

Answer 20

LOcation: Head, body, and tail of epididymis

epithelium:
-Pseudostratified columnar with fewer stereocilla

Support tissues:
-Cicular smooth muscle initially with inner and outer longitudinal layers in the tail

functions:

• sperm maturation and short term storage
• expels sperm at ejaculation

Question 21

Location, epithelium, support tissues and function: Ductus deferens

Answer 21

Location: Extends from epididymis to ejaculatory ducts in prostate gland

epithelium: pseudostratified and simple colimnar

Support tissues:

• Fibroelastic lamina propria
• inner longitudinal, middle circular, outer longitudinal layers of smooth muscle

Function: Carries sperm from the epididymis to the ejaculatory ducts

Question 22

Location, epithelium, support tissues and function: Ejaculatory ducts

Answer 22

Location: Ductus deferens, ducts of the seminal vesicles that come together located in the prostate

epithelium: Pseudostratified and simple columnar

support tissues:

• Fibroelastic tissue
• smooth muscle

function:

• mix sperm and seminal fluid
• deliver semen to urethra
• prostatic secretion is added here

Question 23

Characteristics of the epididymis

Answer 23

Highly elongated and coiled duct where sperm mature in the head, body and tail

Pseudostratified columnar with long stereocilla

• principle cells: columnar cells extending from lumen to basal lamina with stereocilla
• stems cells of principle cells

THin circular layer of smooth muscle cells
in tail region have additional inner and outer longitudinal smooth muscle layers

Sperm maturation consists in acquiring forward motility
mature sperm are stored in tail

Question 24

Characteristics of the Ductus Deferens

Answer 24

A 45 cm long muscular tube lined with pseudostratified columnar epithelia with sparse seterocilla
-supported by CT lamina propria and elastic fibers

Muscular wall:

• inner and outer longitudinal layers
• middle circular layer
• external layer consists of loose CT and adipocytes

Ampulla: dilated portion that leads directly into prostate gland
-distal ends receive the ducts of the seminal vesicle forming the ejaculatory duct

Question 25

What are the 4 male accessory glands?

Answer 25

seminal vesicles (2x)
Prostate gland
Bulbourethral glands (2x)
Urethral glands

Question 26

Characteristics of the seminal vesicles

Answer 26

Alkaline secretion rich in fructose and prostaglandins

• contribute to semen (70%)
• excretory duct penetrates the prostate after joining the ductus deferens where they form the ejaculatory duct

Histology:

• External CT capsule
• Highly folded mucosa lined by pseudostratified colimnar epithelium
• inner circular and outer longitudinal smooth muscle

Question 27

Characteristics of the prostate gland and its various zones

Answer 27

collection of 30-50 tubuloacinar glands that are embedded in a dense fibromuscular stroma, CT capsile

Zones around the urethra:
-Transitional zone (5%): surrounds the superior urethra, contains periurethral mucosal glands

• Central zone (25%): posterior to transition zone, encircles ejaculatory ducts and contains periurethral submucosal glands with longer ducts
• Peripheral (70%) makes up bulk of gland, contains main glands with still longer ducts

individual glads converge but all empty into the prostatic urethra which is the end site of prostatic ducts (prostate secretions) and ejaculatory ducts (semen and secretions from seminal vesicles

Question 28

histology of prostate gland and function

Answer 28

Glands lined by simple columnar or pseudostratified epithelium
-lumen contains corpora amylacea which contains concretions rich in glycoproteins and Ca deposits

Prostate produces a ZN-rich alakline fluid that neutralizes acidic environment of the vagina

provides nutrients and transports sperm and liquefies the semen

Question 29

Characteristics of Bulbourethral glands

Answer 29

Clear mucus like secretion that is a makor component to the preseminal fluid
-lubricates the penile urethra and neutralizes traces of acidic urine

Compound tubuloalveolar glands under the control of testosterone
-lined with simple columnar epithelium

Question 30

Characteristics of the Penis

Answer 30

Consists of cylindrical, columnar masses of erectile tissue

• R/L corpora cavernosa
• ventral corpus spongiosum contains penile urethra

All three erectile tissues comprised of irregular, interconnected vascular sinuses with fibrocollagenous stroma

GLans penis is the distal tip of the corpus spongiosum

Corpora cavernosa are each surrounded by a dense fibroelastic layer, the tunica albuginea

Question 31

How does the erectile tissue work?

Answer 31

Erection involves blood filling the cavernous spaces of erectile tissues, controlled by ANS in the vascular walls

Parasympathetics relax trabecular smooth muscle and diate the helicane arteries that increases blood flow filling of the cavernous spaces

Enlargement compresses dorsal veins against tunica albuginea and blocks the venous outflow and produces rigidity in erectile tissues

At ejaculation the sympathetics constrict the helicane arteries and trabecular muscle which causes the decrease of blood flow into spaces allowing the veins to drain most of the blood