Y2S2 P1 Male Reproductive Anatomy

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Questions and Answers

Which structure primarily contributes to the formation of the glans penis?

Crura of penis

Bulb of penis

Corpus spongiosum (correct)

Corpora cavernosa

What are the two muscles located in the root of the penis?

Ischiocavernosus and bulbospongiosus (correct)

Bulbospongiosus and serratus anterior

Bulbospongiosus and levator ani

Ischiocavernosus and rectus abdominis

Which fascia covers the erectile tissue of the penis?

Buck's fascia (correct)

Superficial fascia

Scarpa's fascia

Endopelvic fascia

What is the primary function of the cavernous nerves in the penis?

Facilitate erection Signup and view all the answers

Which ligaments help support the penis to the pubic symphysis?

Suspensory ligament and fundiform ligament Signup and view all the answers

What is the function of the dorsal arteries of the penis?

Arterial supply to the penis Signup and view all the answers

Which structure separates the left and right corpora cavernosa?

Septum of the penis Signup and view all the answers

What covers the bulb of the penis in the root section?

Deep fascia Signup and view all the answers

In the context of penile anatomy, what role does the tunica albuginea serve?

It is a capsule that surrounds each cavernous body. Signup and view all the answers

During an erection, which structure primarily fills with blood to facilitate the rigidity of the penis?

Corpora cavernosa Signup and view all the answers

Which of the following correctly identifies the muscles associated with the root of the penis?

Ischiocavernosus and bulbospongiosus Signup and view all the answers

What is the primary venous pathway for blood drainage from the penis?

Deep dorsal vein of the penis Signup and view all the answers

Which of the following structures extends from the bulb of the penis?

Corpus spongiosum Signup and view all the answers

What connective tissue structure runs along the linea alba and supports the penis?

Fundiform ligament Signup and view all the answers

What is the optimal temperature for sperm production in the testes?

34°C Signup and view all the answers

Which structure initiates the formation of the vas deferens in the epididymis?

Tail of the epididymis Signup and view all the answers

Which of the following arteries primarily supplies blood to the testes?

Testicular arteries Signup and view all the answers

What role does the pampiniform plexus play in the testes?

Venous drainage Signup and view all the answers

Which cells are primarily responsible for testosterone production in the testes?

Leydig cells Signup and view all the answers

What is the primary hormone produced by Leydig cells in the interstitial space of the testis?

Testosterone Signup and view all the answers

Which of the following correctly describes Sertoli cells' role in male reproductive development?

They form the blood-testis barrier. Signup and view all the answers

What is the primary function of peritubular myoid cells?

Propulsion of spermatozoa Signup and view all the answers

Which component of the testis is responsible for the production of Anti-Mullerian Hormone (AMH)?

Sertoli cells Signup and view all the answers

What structure is the superficial layer surrounding the testis called?

Tunica vaginalis Signup and view all the answers

Which structure serves as the connecting point for the septa dividing the testis into lobules?

Mediastinum testis Signup and view all the answers

What is the role of GDNF released by Sertoli cells?

To ensure self-renewal of spermatogonial stem cells Signup and view all the answers

How are the testes drained lymphatically?

To para-aortic lymph nodes Signup and view all the answers

Which of the following structures is primarily involved in protecting immature sperm from the immune system?

Sertoli cells Signup and view all the answers

What is primarily found within the tunica vasculosa layer of the testis?

Rich vascular supply and connective tissue Signup and view all the answers

What is the primary function of the epididymis?

Storage of sperm Signup and view all the answers

Which structure is responsible for maintaining the optimal temperature of the testes?

Pampiniform plexus Signup and view all the answers

What is the mechanism that allows the testes to descend through the inguinal canal during development?

Embryological descent Signup and view all the answers

What is the source of arterial supply to the testes?

Testicular arteries Signup and view all the answers

Which lymphatic drainage region is associated with the testicles?

Lumbar and para-aortic lymph nodes Signup and view all the answers

What is the primary function of Leydig cells in the interstitial space of the testis?

Production of testosterone Signup and view all the answers

What is the consequence of increased fluid in the space between the layers of the tunica vaginalis?

Hydrocele Signup and view all the answers

Which function is NOT associated with Sertoli cells?

Production of testosterone Signup and view all the answers

How do peritubular myoid cells contribute to the function of the testis?

Propelling spermatozoa towards the vas deferens Signup and view all the answers

What structure serves as the primary barrier protecting immature sperm from the immune system?

Sertoli cells Signup and view all the answers

Which hormone initiates the expression of the SRY gene for male sex determination during embryonic development?

Testosterone Signup and view all the answers

What is the function of the tight junctions formed by Sertoli cells?

Creating the blood-testis barrier Signup and view all the answers

Which layer of the testis connects with the fibrous layer of the surrounding epididymis?

Tunica albuginea Signup and view all the answers

The primary source of testosterone is found in which testicular structure?

Leydig cells Signup and view all the answers

Which layer is not part of the scrotum's structural composition?

Urogenital diaphragm Signup and view all the answers

What is the primary arterial source for the blood supply to the scrotum?

Anterior scrotal artery Signup and view all the answers

Which structure is located within the spermatic cord?

Pampiniform plexus Signup and view all the answers

Which type of epithelium is found in the body and tail of the epididymis?

Cuboidal epithelium Signup and view all the answers

Which nerve is NOT involved in the innervation of the scrotum?

Vagus nerve Signup and view all the answers

What primarily facilitates the reabsorption of fluids in the epididymis?

Epididymal ducts Signup and view all the answers

Which layer of the testis is formed from the transversalis fascia?

Internal spermatic fascia Signup and view all the answers

Which of the following functions is NOT associated with the epididymis?

Production of testosterone Signup and view all the answers

Which layer of the scrotum is primarily responsible for the contraction and relaxation that regulates temperature?

Dartos fascia and muscle Signup and view all the answers

What is the primary role of the pampiniform plexus in the spermatic cord?

Regulating testicular temperature Signup and view all the answers

Which nerve specifically contributes to the sensory innervation of the scrotum?

Perineal branch of pudendal nerve Signup and view all the answers

Which structure directly receives sperm from the rete testis?

Epididymal ducts Signup and view all the answers

Which fascia of the spermatic cord is derived from the transversalis fascia?

Internal spermatic fascia Signup and view all the answers

What type of epithelium is primarily found in the efferent ductules leading to the epididymis?

Ciliated pseudostratified columnar epithelium Signup and view all the answers

What primary structure serves as a protective barrier for immature sperm from the immune system?

Tight junctions of Sertoli cells Signup and view all the answers

What is the primary route for venous drainage from the scrotum?

External pudendal vein Signup and view all the answers

What substance is primarily secreted by the seminal vesicles that aids in nutrition for sperm?

Fructose Signup and view all the answers

What type of epithelium primarily lines the lumen of the vas deferens?

Pseudostratified columnar epithelium Signup and view all the answers

During ejaculation, which structure contracts to aid in moving sperm into the prostatic urethra?

Seminal vesicle Signup and view all the answers

Which arteries are primarily responsible for providing blood supply to the seminal vesicles?

Inferior vesical and internal pudendal arteries Signup and view all the answers

What is the main role of seminal plasmin secreted by the prostate gland?

Acts as an antibiotic to prevent urinary tract infections Signup and view all the answers

Which zone of the prostate gland is most commonly affected by benign prostatic hyperplasia (BPH)?

Transitional zone Signup and view all the answers

What key function does prostate-specific antigen (PSA) perform after ejaculation?

Liqueifies semen Signup and view all the answers

Which structure is primarily responsible for the production of lubricating mucus in the male reproductive system?

Bulbourethral glands Signup and view all the answers

What type of epithelium is predominantly found in the tubuloalveolar glands of the prostate gland?

Cuboidal and columnar epithelium Signup and view all the answers

Which zone of the prostate gland is known to comprise the largest portion by volume?

Peripheral zone Signup and view all the answers

Where does the prostatic part of the urethra primarily travel through?

Through the prostate gland Signup and view all the answers

Which of the following structures is primarily involved in the arterial supply to the prostate gland?

Internal iliac arteries Signup and view all the answers

Which layer of smooth muscle is arranged longitudinally in the vas deferens?

Outer layer Signup and view all the answers

What is the primary secretion of the seminal vesicles during ejaculation?

Thick viscous fluid Signup and view all the answers

What type of epithelium lines the lumen of the vas deferens?

Pseudostratified columnar epithelium with stereocilia Signup and view all the answers

Which arteries primarily supply blood to the seminal vesicles?

Inferior vesical and internal pudendal arteries Signup and view all the answers

During the ejaculation process, what role do the smooth muscles of the seminal vesicles play?

Contract to flush sperm into the ejaculatory duct Signup and view all the answers

What is the primary function of prostate-specific antigen (PSA)?

Liquefying semen after ejaculation Signup and view all the answers

Which zone of the prostate commonly undergoes benign prostatic hyperplasia (BPH)?

Transitional zone Signup and view all the answers

What is the arterial supply to the prostate gland primarily derived from?

Prostatic arteries from internal iliac arteries Signup and view all the answers

Which component of prostatic secretions provides nourishment?

Citric acid Signup and view all the answers

What is the primary function of the bulbourethral glands (Cowper's glands)?

Lubrication of the urethra Signup and view all the answers

Which of the following correctly describes the epithelium composition within the prostate gland?

Pseudostratified, cuboidal, and columnar epithelium Signup and view all the answers

What is the function of seminal plasmin produced by the prostate?

Providing protection against infections Signup and view all the answers

Which part of the prostate gland has the highest volume contribution?

Peripheral zone Signup and view all the answers

Study Notes

Penis Structure

The penis is the external male reproductive organ divided into three parts: root, body, and glans.
The root is the fixed portion located in the perineal pouch, containing three erectile tissues (two crura and a bulb) and two muscles (ischiocavernosus and bulbospongiosus).
The body is the free portion suspended from the pubic symphysis, composed of three erectile tissue cylinders (two corpora cavernosa and corpus spongiosum).
The glans is the most distal part formed from the distal expansion of the corpus spongiosum, containing the external urethral orifice.

Erectile Tissue

Erectile tissue engorges with blood during sexual arousal, leading to an erection.
The root consists of left and right crura (covered by ischiocavernosus muscles) and the bulb of the penis (midline).
The body comprises left and right corpora cavernosa (formed from the left and right crura) separated by the septum of the penis and the corpus spongiosum (formed from the bulb of the penis, located ventrally).
The glans is formed by the distal expansion of the corpus spongiosum.

Fascia and Ligaments

The penis is covered by several layers of fascia.
Superficial fascia, also known as Colles' fascia, is continuous with Scarpa's fascia.
Deep fascia, known as Buck's fascia, is continuous with the deep perineal fascia.
Tunica albuginea is a capsule surrounding each cavernous body and fused midline at the septum.
The suspensory ligament is a condensation of deep fascia connective erectile bodies to the pubic symphysis.
The fundiform ligament is a condensation of abdominal subcutaneous tissue running down the linea alba, surrounding the penis like a sling and attaching it to the pubic symphysis.

Neurovasculature

The penis receives arterial supply from the dorsal arteries of the penis, deep arteries of the penis, and the bulbourethral artery, which are branches of the internal pudendal artery.
Venous drainage occurs through the deep dorsal vein of the penis, which connects to the prostatic venous plexus (cavernous spaces) and superficial dorsal veins (skin and subcutaneous tissue).
Innervation is provided by the dorsal nerve of the penis (pudendal nerve), which carries sensory and sympathetic nerve fibers, and the cavernous nerves (from the periprostatic plexus), responsible for erection.

Penis Anatomy

The penis is the external organ of the male reproductive system.
It is divided into three parts: the root, the body, and the glans.

Root

Located within the superficial perineal pouch.
Consists of three erectile tissues: two crura and the bulb.
Also contains two muscles: ischiocavernosus and bulbospongiosus.

Body

The free portion of the penis, suspended from the pubic symphysis.
Composed of three cylinders of erectile tissue: two corpora cavernosa and the corpus spongiosum.

Glans

The most distal part of the penis, formed from the distal expansion of the corpus spongiosum.
Contains the external urethral orifice.

Erectile Tissue

Engorges with blood during sexual arousal to produce an erection.
The root contains the left and right crura (covered by paired ischiocavernosus muscles) and the bulb of the penis (midline).
The body is made up of the left and right corpora cavernosa (formed from the left and right crura), separated by the septum of the penis, and the corpus spongiosum (formed from the bulb of the penis, which lies ventrally).
The glans is formed from the distal expansion of the corpus spongiosum.

Fascia

Covers the erectile tissue of the penis.
Superficial fascia: Colles' fascia (continuous with Scarpa's fascia).
Deep fascia: Buck's fascia (continuous with deep perineal fascia).
Tunica albuginea: capsule around each cavernous body, fused midline at the septum.

Ligaments

Suspensory ligament: condensation of deep fascia connecting erectile bodies to the pubic symphysis.
Fundiform ligament: condensation of abdominal subcutaneous tissue running down the linea alba and surrounding the penis like a sling.
The fundiform ligament attaches the penis to the pubic symphysis.

Neurovasculature

Arterial supply: dorsal arteries of the penis, deep arteries of the penis, and the bulbourethral artery (branches of the internal pudendal artery).
Venous drainage: deep dorsal vein of the penis, which drains into the prostatic venous plexus (cavernous spaces); superficial dorsal veins (skin and subcutaneous tissue).
Innervation: sensory and sympathetic innervation via the dorsal nerve of the penis (pudendal nerve); parasympathetic innervation via cavernous nerves (periprostatic plexus, responsible for erection).

Testes and Epididymis

Paired structures located within the scrotum
Testes are responsible for sperm production and hormone (testosterone) synthesis
Epididymis stores sperm
Suspended from the abdomen by the spermatic cord
Spermatic cord is a structure formed during development, as the testes descend from the abdomen through the inguinal canal

Epididymis

Head: Formed from efferent tubules of the testes
Body: Heavily coiled duct of the epididymis
Tail: Origin of the vas deferens

Testes Neurovasculature

Arterial supply: Testicular arteries (arise from the abdominal aorta)
- Anastomose with the cremasteric artery (branch of the inferior epigastric artery) and the artery of the vas deferens (branch of the inferior vesical artery)
Venous drainage: Pampiniform plexus → testicular veins
- Left testicular vein → left renal vein
- Right testicular vein → inferior vena cava (IVC)
Lymphatic drainage: Lumbar and para-aortic lymph nodes
Innervation: Testicular plexus (autonomic nervous system - ANS and sensory) - derived from renal and aortic plexus

Testis Histology

Each testis consists of highly-coiled seminiferous tubules and interstitium
Optimal temperature for testes: 34°C
- Maintained by:
  - Embryological descent of the testes via the inguinal canal before birth from the abdomen
  - Cremaster muscle (skeletal muscle) which raises the testes in response to cold, sex, or fear
  - Dartos muscle (smooth muscle) which changes the surface area of the scrotum to regulate temperature → wrinkling of the testicles
  - Pampiniform plexus of testicular veins
Functions:
- Spermatogenesis
- Androgen (testosterone) production

Seminiferous Tubules

Complex stratified epithelium (cuboidal cells)
- Germ cells: Migrate from germ line stem cells to become spermatids (via spermatogenesis) and spermatozoa (via spermiogenesis)
  - Spermatozoa are released into the fluid-filled lumen
  - Maturation process is supported by Sertoli cells
Peritubular myoid cells: Thin, contractile cells that line the external tubule
- Functions:
  - Propel spermatozoa towards the vas deferens
  - Structural support

Sertoli Cells

Tree-shaped columnar cells with tall cytoplasm that extends from the basal lamina to the lumen
Respond to follicle stimulating hormone (FSH) to execute functions
Functions:
- Sex determination: Expression of the SRY gene (sex-determining factor on the Y chromosome) during embryonic development to initiate male sex determination
- Developmental: Production of Anti-Müllerian Hormone (AMH) during early fetal life, which causes regression of female internal organs
- Hormonal regulation: Release of inhibins and activins to regulate FSH secretion
- Stem cell regulation: Release of GDNF to ensure self-renewal of spermatogonial stem cells
- Spermatogenesis: Support spermatogenesis by responding to FSH and testosterone
- Forms the blood-testis barrier: Tight junctions, desmosomes, and gap junctions protect immature sperm from the immune system

Interstitial Space

Primary component: Leydig cells
- Primary source of testosterone
- Produce testosterone in response to luteinizing hormone (LH) from the pituitary gland
- Testosterone produced either:
  - Diffuses into the seminiferous tubules
  - Enters the peripheral circulation to drive male reproductive development
- Contain Crystals of Reinke - rod-shaped structures
- Abundant smooth endoplasmic reticulum (SER) for testosterone production

Layers of the Testis

Tunica vaginalis (most superficial)
- Two layers:
  - Parietal layer lines the scrotal cavity
  - Visceral layer overlays the tunica albuginea
- Separated by a thin layer of fluid to reduce friction
  - Increased fluid in this space → hydrocele
Tunica albuginea
- Connects with the fibrous layer surrounding the epididymis
- Divides the testes into lobules – forms septa between each lobule
  - Meeting point of septa = mediastinum
Tunica vasculosa
- Innermost layer
- Consists of a rich vascular supply and connective tissue

Descent of the Testes

Testes originate and descend from the abdomen during gestation
This is why they drain to para-aortic lymph nodes as opposed to the scrotum, which drains to superficial inguinal lymph nodes
An evagination of the peritoneum (processus vaginalis) descends with the transversalis and internal oblique muscles

Testes and Epididymis

Paired structures located within the scrotum
Responsible for sperm production and hormone synthesis

Position

Suspended from the abdomen by the spermatic cord
Descend through the inguinal canal during development

Epididymis

Head: Formed from efferent tubules of the testes
Body: Heavily coiled duct of the epididymis
Tail: Origin of vas deferens

Testis Neurovasculature

Arterial supply: Testicular arteries (arise from abdominal aorta)
- Anastomoses with cremasteric artery and artery of the vas deferens
Venous drainage: Pampiniform plexus → testicular veins
- Left testicular vein → left renal vein
- Right testicular vein → IVC
Lymphatic drainage: Lumbar and para-aortic lymph nodes
Innervation: Testicular plexus (ANS and sensory) - derived from renal and aortic plexus

Testis Composition

Highly-coiled seminiferous tubules and interstitium
Optimal temperature of 34°C maintained by:
- Embryological descent via the inguinal canal before birth
- Cremaster muscle
- Dartos muscle
- Pampiniform plexus of testicular veins

Testis Functions

Spermatogenesis
Androgen (testosterone) production

Histology of the Testis: Seminiferous Tubules

Complex stratified epithelium
Contains migrating germ line stem cells which become spermatids (via spermatogenesis) and spermatozoa (via spermiogenesis)
Spermatozoa are released into the fluid-filled lumen
Maturation process supported by Sertoli cells

Histology of the Testis: Peritubular Myoid Cells

Thin, contractile cells lining the external tubule
Functions:
- Propel spermatozoa towards the vas deferens
- Structural support

Histology of the Testis: Sertoli Cells

Tree-shaped columnar cells extending from the basal lamina to the lumen
Respond to FSH to execute functions
Functions:
- Sex determination (expression of SRY gene)
- Developmental (production of AMH)
- Hormonal regulation (release of inhibins and activins)
- Stem cell regulation (release of GDNF)
- Spermatogenesis (supported by FSH and testosterone)
- Form the blood-testis barrier (protection of immature sperm)

Histology of the Testis: Interstitial Space

Primary component: Leydig cells
- Primary source of testosterone
- Produce testosterone in response to LH
- Testosterone either diffuses into seminiferous tubules or enters the peripheral circulation
- Contain Crystals of Reinke
- Abundant SER (for testosterone production)

Layers of the Testis

Tunica vaginalis (most superficial)
- 2 layers: parietal and visceral
- Separated by a thin layer of fluid to reduce friction
Tunica albuginea
- Connects with the fibrous layer of the epididymis
- Divides the testes into lobules
Tunica vasculosa
- Innermost layer
- Consists of rich vascular supply and connective tissue

Descent of the Testes

Originates and descend from the abdomen during gestation
Drains to para-aortic lymph nodes (due to abdominal origin)
An evagination of the peritoneum (processus vaginalis) descending with transversalis and internal oblique muscles

Scrotum

The scrotum is a sac of skin that contains the testes.
The scrotum is composed of several layers, including skin, dartos fascia and muscle, external spermatic fascia, cremasteric fascia, internal spermatic fascia, tunica vaginalis, and tunica albuginea.
The scrotum is supplied by the anterior and posterior scrotal arteries, drained by the scrotal veins, and innervated by the anterior and posterior scrotal nerves.

Spermatic Cord

The spermatic cord is a structure that connects the testes to the abdomen.
The spermatic cord is formed at the opening of the inguinal canal and continues into the scrotum.
The spermatic cord contains various structures including vessels (testicular artery, pampiniform plexus of testicular veins, cremasteric artery and veins, artery to vas deferens), nerves (genital branch of genitofemoral nerve, ANS), vas deferens, processus vaginalis, and lymphatic vessels.
The spermatic cord is surrounded by fascial coverings derived from the external oblique, internal oblique, and transversalis fascia.

Histology of Ejaculatory Ducts + Accessory Glands

The rete testis are a network of passages that allow sperm to exit the testis into the epididymis via efferent ductules.
The epididymis stores sperm and allows them to mature.
The epididymis contains:
- Ciliated pseudostratified columnar epithelium: becomes cuboidal epithelium in the body and tail, allowing for a larger lumen in these areas
- Apical stereocilia (non-motile): propel sperm
- Epididymal ducts: fluid reabsorption
- Peritubular smooth muscle: becomes thicker as the epididymis approaches the vas deferens.

Scrotum

The scrotum is a sac of skin that encloses the testicles and is composed of several layers:
- Skin: The outermost layer.
- Dartos fascia and muscle: A layer of smooth muscle that contracts to wrinkle the skin of the scrotum, helping to regulate temperature.
- External spermatic fascia: Derived from the external oblique muscle.
- Cremasteric fascia: Derived from the internal oblique muscle.
- Internal spermatic fascia: Derived from the transversalis fascia.
- Tunica vaginalis: A serous membrane that lines the scrotum and partially covers the testicle.
- Tunica albuginea: A dense fibrous capsule that surrounds the testicle.
Blood supply comes from the anterior scrotal artery (branch of the external pudendal artery) and the posterior scrotal artery (branch of the internal pudendal artery).
Venous drainage occurs through the scrotal veins, which join the external pudendal vein.
Lymphatic drainage occurs through the superficial inguinal nodes.
Innervation comes from the anterior scrotal nerves (from the genital branch of the genitofemoral nerve and the ilioinguinal nerve) and posterior scrotal nerves (from the perineal branch of the pudendal nerve and the posterior femoral cutaneous nerve).

Spermatic Cord

The spermatic cord is formed at the opening of the inguinal canal called the deep inguinal ring.
The spermatic cord travels through the inguinal canal, exits through the superficial inguinal ring, and continues into the scrotum.
Structures within the spermatic cord are covered by multiple layers of fascia:
- External spermatic fascia: Derived from the external oblique muscle.
- Cremasteric muscle and fascia: Derived from the internal oblique muscle.
- Internal spermatic fascia: Derived from the transversalis fascia.
The spermatic cord contains:
- Vessels: Testicular artery, pampiniform plexus of testicular veins, cremasteric artery and veins, artery to vas deferens
- Nerves: Genital branch of genitofemoral nerve, autonomic nervous system (ANS)
- Vas deferens: A muscular tube that carries sperm from the epididymis.
- Processus vaginalis: An outpouching of the peritoneum that descends into the scrotum during development.
- Lymphatic vessels

Histology of Ejaculatory Ducts + Accessory Glands

Rete testis: A network of tubules in the testis that connect the seminiferous tubules to the efferent ductules.
Epididymis: A coiled tube on the posterior surface of the testis where sperm mature and are stored before ejaculation.
- The epididymis is composed of:
  - Ciliated pseudostratified columnar epithelium: In the head of the epididymis. Becomes cuboidal epithelium in the body and tail (allowing for a larger lumen).
  - Apical stereocilia: In the epididymis, they are non-motile and function to propel sperm.
  - Epididymal ducts: Function in fluid reabsorption.
  - Peritubular smooth muscle: Gets thicker as the epididymis approaches the vas deferens.

Vas Deferens

A tube that carries sperm from the epididymis to the ejaculatory duct
Has a similar epithelial lining to the epididymis, but with a thicker muscular wall
Courses through the inguinal canal as part of the spermatic cord
Joins with the duct from the seminal vesicle to form the ejaculatory duct, which opens into the prostatic urethra
Lined with a mucosa consisting of a lamina propria and secretory pseudostratiﬁed columnar epithelium with apical stereocilia
Composed of three layers of smooth muscle: inner longitudinal, middle circular, and outer longitudinal
Functions in sperm transport and absorption

Seminal Vesicles

Paired glands located between the fundus of the bladder and rectum
Contribute the majority of seminal fluid volume
Their ducts merge with the vas deferens to form the ejaculatory duct
Inervated sympathetically and supplied by the inferior vesical, internal pudendal, and middle rectal arteries
Lined with pseudostratiﬁed columnar epithelium
Contract during ejaculation to flush sperm into the prostatic urethra
Secrete a viscous fluid containing fructose, sugars, and ascorbic acid, which combines with prostatic secretions to form ejaculate

Prostate Gland

A walnut-shaped gland located inferior to the bladder and superior to the external urethral sphincter
Can be divided into lobes and zones: median, transitional, peripheral, and fibromuscular stroma
Secretes citric acid, seminal plasmin, and prostate-specific antigen (PSA)
Common site for benign prostatic hyperplasia (BPH) and cancer
Supplied by prostatic arteries and drained by prostatic venous plexus which connects to Batson venous plexus
Innervated by the inferior hypogastric plexus

Bulbourethral Glands

Also known as Cowper's glands
Located posterolateral to the membranous urethra
Produce lubricating mucus that contributes to semen volume
Lined with columnar epithelium and open into the proximal portion of the spongy urethra

Vas Deferens

A tube that carries sperm from the epididymis to the ejaculatory duct.
Has a thicker muscular wall than the epididymal tubules.
Passes through the inguinal canal as part of the spermatic cord.
Joins with the duct from the seminal vesicle to form the ejaculatory duct, which opens into the prostatic urethra.
Lined with a pseudostratified columnar epithelium with apical stereocilia.
Has three layers of smooth muscle: inner longitudinal, middle circular, and outer longitudinal.
Functions in the contraction and movement of sperm, as well as the absorption of sperm.

Seminal Vesicles

Paired glands located between the bladder and rectum.
Secrete the majority of the constituents of semen.
Produce a viscous fluid containing fructose, sugars, and ascorbic acid (seminal fluid).
Join with the vas deferens to form the ejaculatory duct.
Contraction during ejaculation flushes sperm from the vas deferens into the prostatic urethra.
Are androgen-dependent, meaning they are influenced by testosterone.

Prostate Gland

A walnut-shaped gland located inferior to the bladder and superior to the external urethral sphincter.
Divided into zones, including the central zone, transitional zone, peripheral zone, and fibromuscular stroma.
Secretes citric acid, seminal plasmin, PSA, and proteolytic enzymes.
Enlarges with age.
The prostatic urethra passes through the prostate.

Bulbourethral Glands

Also known as Cowper's glands, these are located posterolateral to the membranous urethra.
Secrete a lubricating mucus that contributes to the final volume of semen.
Have tubuloalveolar glands lined by columnar epithelium.
Open into the proximal portion of the spongy urethra.

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