AHE II 4.1 - REPRODUCTIVE SYSTEM (PART 1: INTRODUCTION; MALES)

• Course objective is to identify the gross anatomical structures of the male and female reproductive system
• Goal is to contextualize anatomical structures role in the body

Lecture Learning Objectives

• Define the pelvis regions using defining structures
• Describe the role of the pelvic floor, its parts, and functions of the pelvic diaphragm
• Explain the anatomical relationship between the perineal membrane plus the deep and superficial perineal pouches
• Describe the functions, contents, and visually identify the parts of the:
  • Perineal membrane
  • Deep perineal pouch
  • Superficial perineal pouch
  • Perineal body
• Compare the differences between the male and female perineum
• Describe the importance of the ischio-anal fossae and Colles’ fascia
• Indicate their relationship to other structures and their role in the spread of infection
• List the layers and attachments of the pelvic fascia
• Recognize the structures they do and do not cover
• Visually identify each major component of the male reproductive system
• Describe its primary function and additional components if present
• List the tissue layers covering the testes and penis
• Recall the pathway of spermatozoa, from the seminiferous tubules to outside the body
• Visually identify and recall the structures supplied by the pelvic vasculature

Pelvis Terminology

• The pelvic cavity is a bowl-shaped space defined by the pelvic girdle bones of the os coxa, sacrum, and coccyx
• Defined by the pelvic inlet, pelvic outlet, and pelvic floor
• Pelvic cavity contains the internal reproductive organs
• Pelvic girdle is a bony ring created by three bones
• Pelvic girdle forms the pelvic inlet and pelvic outlet
• True pelvis is the inferior part of the os coxa, sacrum, and coccyx
• True pelvis is bounded by the pelvic inlet and outlet
• Perineum is inferior to the floor of the pelvic cavity
• It is a shallow compartment bound by the pelvic outlet
• Contains/Supports external genitalia, openings of the genitourinary and GI tract

Pelvic Floor

• A series of structures that separates the pelvic cavity from the perineum
• Formed by the pelvic diaphragm, which is the muscular portion
• Perineal membrane is a thick, rectangular CT structure attached to the arch formed by the pubis
• Deep perineal pouch is formed by the perineal membrane
• Deep perineal ouch contains a layer of skeletal muscles, nerves, and vessels

Pelvic Diaphragm

• The muscular part of pelvic floor
• Attached to the walls of the pelvic girdle
• Shaped like a bowl or funnel
• Urogenital hiatus provides an opening for vessels, nerves, and urogenital and GI tracts
• The pelvic diaphragm is comprised of the urogenital hiatus, the levator ani muscles, the coccygeus muscle and the anococcygeal ligament.
• The levator ani muscles are attached to the anococcygeal ligament and pelvic girdle
  • Includes puborectalis, pubococcygeus, and iliococcygeus
• Functions
  • Supports pelvic viscera
  • Functions as the vaginal sphincter in females
  • Maintains the angle between the rectum and anal canal
  • Reinforces the external anal sphincter
• Coccygeus muscles:
  • Supports pelvic viscera
  • Pulls coccyx forward after defecation

Pelvic Diaphragm - Passages

• Two openings are created by pelvic girdle, sacrotuberous and sacrospinous ligaments, and piriformis muscle
• These generate passages for neurovascular structures in the pelvis that go to gluteal and perineal regions
• The greater sciatic foramen is an opening between the pelvic cavity and the gluteal region of the lower limb
• Greater sciatic foramen is divided by the piriformis muscle
  • The Sciatic nerve runs through it
  • The inferior and superior gluteal vessels and nerves travel above and below the piriformis muscle
  • Includes the Pudendal nerve and Internal pudendal artery and vein
• The lesser sciatic foramen is an opening from the gluteal region to perineum in pelvic cavity
  • Contains the pudendal canal
  • Contains the pudendal nerve and internal pudendal artery and vein

Perineum

• The perineum is a diamond-shaped region between the thighs
• The borders are the superior pelvic diaphragm, and the pelvic outlet at four corners:
  • The pubic symphysis, two ischial tuberosities, and the coccyx
• The perineum is divided into two triangles:
  • The urogenital triangle contains openings for the urinary and reproductive systems and is an anchor for external genitalia
    • Contains perineal pouches and membranes
  • The anal triangle contains the anus and external anal sphincter

Perineal Membrane

• The perineal membrane is a thick, horizontal, and rectangular shaped fascia that is inferior to the pelvic diaphragm
• It has lateral attachment to the ischiopubic rami and is free anteriorly and posteriorly
• Defines the deep and superficial perineal pouches and ischioanal fossae
• Provides attachment site for the roots of the external genitalia and associated muscles

Deep Perineal Pouch

• A thin space between the pelvic diaphragm muscles and the perineal membrane
• Continuous with the pelvic cavity via the urogenital hiatus
• Contains skeletal muscle sphincters, stabilizers, and neurovascular elements
• Allows passage for the urethra and vagina.
• Includes the external urethral sphincter and deep transverse perineal muscle
• Also includes the Sphincter urethrovaginalis, in females
• And Compressor urethrae, in females too
• The internal pudendal artery and vein run through the pudendal canal to this space
• The pudendal nerve becomes the dorsal nerve of the penis/clitoris in this pouch

Superficial Perineal Pouch

• Found in the urogenital triangle, between integument and perineal membrane
• Contains erectile tissue of the reproductive system, namely penis and clitoris
• Contains skeletal muscle that is associated with erectile structures, namely :
  • Ischiocavernosus muscle
  • Bulbospongiosus muscle
  • Superficial transverse perineal muscle

Perineal Body

• Connective tissue structure is located and attached, to posterior perineal membrane at midline
• Attachment for numerous urogenital structures, including superficial and deep transverse perineal muscles
• The perineal body is an attachment for the Sphincter urethrovaginalis, External anal sphincter, and Bulbospongiosus muscle
• Serves as the posterior border of urogenital hiatus

Ischio-anal Fossae

• Created by the levator ani muscles and pelvic walls; divided by anal aperture
• Allows movement of the pelvic diaphragm and expansion of the anal canal during defecation
• Creates gutters on the sides of the perineum, deep to the deep perineal pouch
• Common location for infection if anal mucosa is injured/torn

Superficial Pelvic Fascia

• Camper's fascia - superficial fatty fascia
• Scarpa's fascia- deep membranous fascia
  • Posterior border - attached to the perineal membrane
  • Lateral border - Ischiopubic rami at lateral border of urogenital triangle
• Contains the Superficial fascia of the penis (Colles')
• Also contains the Dartos fascia in the scrotum and the superficial perineal fascia
• Buck’s Fascia encompasses erectile tissue

Male Reproductive System

• Major Components are located in the abdomen, pelvis, and perineum
• Consists of ducts and tubules allowing for the passage of gametes from gonads to the external body
• Includes the:
  • Testes
  • Epididymis
  • Ductus deferens
  • Ejaculatory duct
  • Urethra
  • Penis
  • Prostate
  • Seminal vesicles
  • Bulbourethral glands

Context for Testes

• Testes develop high on the posterior abdominal wall
• Descend around the time of birth
• Travel through the inguinal canal in the anterior abdominal wall into the scrotum of the perineum
• Carry vessels, lymphatics, nerves, and the ductus deferens

Vascular Supply to Testes

• Testicular arteries and veins supply blood

Testes

• The main function is as the location of sperm production and maturation
• Has several layers of tissue to include from external to internal:
  • Scrotum
  • Musculofacial pouch (Dartos fascia)
  • External spermatic fascia
  • Cremaster muscle
  • Internal spermatic fascia
  • Tunica vaginalis- (parietal and visceral layers)
  • Tunica albuginea
• Spermatic cord is a tube-like connection between the pouch in the scrotum and the abdominal wall
  • Contains the vas deferens, the testicular artery, testicular veins, and the cremaster muscle
• Composed of seminiferous tubules and interstitial tissue
• Tunica albuginea is their connective tissue capsule
• Pathway
  • Seminiferous tubules are the location where spermatozoa are produced
  • Rete testis is the collecting chamber for spermatozoa after leaving the seminiferous tubules, and is within the thick CT of the mediastinum testes
  • Efferent ductules are the tubes that run from the rete testis into the epididymis

Epididymis

• Location where spermatozoa become mobile and gain the ability to fertilize eggs
• Location where spermatozoa are stored before ejaculation
• Single, long, coiled duct on the posterolateral side of the testis
• Efferent ductules- coiled mass that forms the head of the epididymis
• True epididymis –single duct that forms the body and tail of the epididymis
• continuous with the ductus deferens

Ductus Deferens

• A long muscular duct that transports spermatozoa from the epididymis to the ejaculatory duct in pelvic cavity
• Ascends through spermatic cord, entering abdominal cavity through inguinal canal
• Enters pelvic cavity deep to peritoneum then descends on lateral side of bladder
• Joins with the seminal vesicle duct to form the ejaculatory duct within the prostate gland
• Joins the urethra

Inguinal Canal

• A canal created by the fascia of the abdominal muscles
• Passageway from the deep inguinal ring/ligament, ending at the superficial inguinal ring
• Bound inferiorly by the inguinal ligament
• Contains inguinal nerve and spermatic cord
  • The spermatic cord has cremasteric muscle and the genital branch of the genitofemoral nerve
  • It also contains the testicular artery and vein and the ductus deferens
• Crosses over/superficial to the external iliac artery and vein

Seminal Vesicles

• Accessory glands in males, that produce secretions that contribute to semen/ejaculate
• The seminal vesicles are encapsulated with CT forming coiled tubes with numerous pocket-like outgrowths
• Sits between the bladder and the rectum, lateral to ductus deferens at bladder base
• Joins with the ductus deferens to form the ejaculatory duct
• Ejaculatory duct is the shared connection to the urethra

Prostate

• Functions to form secretions that contribute to the formation of semen
• The prostate is an unpaired accessory organ that has about 30-40 individual glands
• Located inferior to the bladder, and anterior to the rectum
• Continuous superiorly with the neck of the bladder
• Contains the urethra and ejaculatory duct
• Inferior surface is cradled by levator ani muscles of the pelvic diaphragm

Bulbourethral Gland

• Produces sections that contribute to lubrication of the urethra
• Also helps with pre-ejaculatory emission from the penis
• These are paired, pea-shaped mucous glands and are held within the deep perineal pouch
• Lateral to the urethra after it exits the prostate
• Bulb of the spongy urethra at root of the penis

Penis

• Function is the transportation of urine and semen
• The root of the penis consists of the proximal parts of corpora cavernosa (cura) and the spongiosum (bulb of penis)
• The body is layered superficial to deep from the skin, superficial/Dartos fascia, areolar CT, deep/Buck's fascia, tunica albudenia and finally erectile tissue
• Supported by the suspensory ligament, attached to the pubic symphysis and the fundiform ligament
• The glans are composed of corpus spongiosum
• Erectile tissue is covered in Buck's fascia
• The corpora cavernosa is paired and erecticle; attached to each side of the urogenital triangle, anchored to pubic arch (crura- attached parts)
• The corpus spongiosum is the single mass of erectile tissue that directly surrounds urethra and extends from it into the glans
• Attached to the perineal membrane (bulb of the penis)

Urethra

• Prostatic urethra
• Membranous urethra
• Spongy urethra

Vascular Supply

• Includes the Umbilical artery, Obturator artery, and inferior vesical artery
• Internal iliac artery allows for the anterior trunk
• Internal pudendal artery supplies the dorsal artery and vein of the penis
• Also the perineal artery and posterior scrotal artery, as well as the testicular arteries and veins
• The deep artery of penis, the dorsal arteries of the penis as well as the urethral arteries run through the erectile tissue
• Perineal artery, vein, and nerve feed the area
• A Of the bulb of the penis, and internal pudendal are the main suppliers