Anatomy and histology of the male pelvis Flashcards
What are the borders of the male pelvis?
Roof is the peritoneum
What is the precursor to the bladder?
The allantosis
What is the urogenital sinus?
Located in the base of the cloaca and consists of the primitive urinary and lower reproductive systems prior to separation. Upper reproductive systems form from the Wollffian or Mullerian duct.
What is the male urogenital sinus?
Prostatic gland, prostatic urethra and Cowper’s gland.
What is the female urogenital sinus?
Lower vagina, Bartholin’s gland and urethral and paraurethral gland
What is the cloaca?
Component of the hindgut which consists of the urogenitals and the rectum.
What happens to the cloaca during development?
It becomes seprated by anorectal septation to maintain a separate urinary and rectal passage.
What is the mesonephros?
Temporary kidney during development. It has Wollffian duct directly leading from it to the bladder allantosis. Laterally surrounded by the Mullerian duct.
What is the Cowper’s glands?
Produces pre-ejaculatory fluid to cleanse and purify the urethra.
What is the metanephros?
Embryological precursor to the kidneys.
What is the role of the Wollffian duct?
Carries contents from the mesonephros and metanephros to the bladder. Becomes the male internal genitalia.
What is the role of the Mullerian duct?
Carries contents directly to the bladder and becomes the female internal genitalia which is the upper vagina, uterus.
What is the paramesophric duct?
Mullerian duct.
What is the mesonephric duct?
Wollffian duct.
What is the epidydymis?
On top of the testes which contain and store mature sperm.
What is the seminal vesicle?
Produces seminal fluid to nourish and give sperm nutrients.
What is the vas deferens?
Tract which carries mature sperm from the epidymis to empty into the ejaculatory duct so sperm will be in the urethra. It is part of the spermatic cord.
What is the spermatic cord?
Passes through the inguinal canal and suspends the testes. Contains the testicular artery and the vas deferens.
Which ducts and glands are present on the posterior surface of the male bladder?
Ductus deferens and seminal vesicle
What are the histological zones of the urethra?
Pseudostratified columnar epithelia, stratified squamous epithelia and transitional epithelia.
Which region of the prostate is responsible for benign prostatic enlargement?
Central zone surrounds the ejaculatory ducts and contains the transitional zone and paraurethral zone surrounding the bladder and peripheral zone
Which region of the prostate is responsible for carcinoma?
The peripheral zone.
What is the function of the prostate gland?
Produces fluid that makes up the non-sperm part of semen.
What are the components of the male urethra?
Prostatic zone, membranous zone and spongy/penile zone
What is the prostatic zone?
Contains transitional epithelia. It is the widest part of the urethra which transmit urine or semen into the urogenitary tract. Urinary incontinence is affected here.
What is the membranous zone?
Contains psuedostratified columnar epithelia. It consists of perineal muscle and carries urine and semen out of the ody. It is where you hold urine and surrounded by the external anal sphincter
What is the spongy/penile zone?
Contains stratified squamous non keratinising. It transmit urine or semen out of the body.
What is the perineum?
Skin between the genitals and the anus. It has a superior and deep perineal pouch
What are the borders of the perineum?
Roof is the pelvic diaphragm formed of the coccygeus and levator ani muscles. It has 2 hiatus; urogenital hiatus and anal hiatus.
What is the pelvic diaphragm?
Muscles which consist of the coccygeus and levator ani and form the roof of the perineum
What is the perineal membrane?
Membrane overlying the perineum and is separated into a superior and inferior perineal pouch.
What covers most of the pelvic outlet?
Pelvic diaphragm
What is the levator ani?
Striated smooth muscle; Iliococcygeus, pubococcygeus and muscles and puborectalis
What is the space between the perineal membrane and pelvic diaphragm?
Ilio-ischioanal fossae
What is the deep perineal pouch?
Space between the perineal membrane and the deeper muscles such as the pevlic diaphragm and levator ani.
What are the divisions of the urogenital triangle?
Anterior border is pelvic diaphragm, Posterior border is the transverse perineal muscle. Roof is peritoenal cavity and floor is the perineum
How does the penis develop from the indifferent stage?
Genital tubercle enlarges and becomes the glans penis, the tubercle swellings becomes the scrotum where the testes are contained and the urogenital fold zips to become the urethra and the urogenital groove enlarges to become the shaft of the penis.
What is the function of the corpus cavernosus?
Forms most of the penis and contains blood vessels that fill to cause erection
What is the function of the corpus spongiosum?
Surrounds urethra and vascularised to cause erection.
What surrounds the corpus cavernosus?
Ischiocavernosus muscle
What surrounds the corpus spongiosum?
Bulbospongiosus muscle
What provides most of the innervation to the perineum?
Pudendal nerve provides sensory and motor innervatin.
How can cycling for long periods of time affect the perineum?
Can lead to impotence due to compression of the pudendal nerve
What is the parasympathetic innervation to the perineum?
The parasypathetic fibres from S2-S4 via vagus which cause vasodilation, erection and urination via relaxation of the internal urethral sphincter
What is the sympathetic innervation to the perineum?
Sympathetic fibres from T10-L2 and it causes vasoconstriction, smooth muscle contraction of the internal anal sphincter to prevent urination and cause ejaculation
What is the blood supply to the perineum and penis excluding the testes?
Internal pudendal artery which is a branch of the internal iliac
What is the venous drainage of the perineum?
Internal pudendal vein into the internal iliac vein. The deep dorsal vein drains the glans penis and the corpus cavernosus into the prostate plexus.
Bony landmarks of perineum?
Pubic symphysis, ischial tuberosities and coccyx
Which muscle supports the anus?
Levator ani
Which muscle must be relaxed for defecation?
Puborectal muscle
Anterior ischioanal fossa
Where blood supply and fat is found. Located between perineal membrane and levator ani
Space between perineal membrane and fascia?
Superior perineal pouch
Where are male erectile tissues found?
Superior perineal pouch- this will have the corpus cavernosus and corpus spongiosum
Surrounds the male urethra and fills with blood for erection?
Corpus spongiosum
Raffe
Scar at end of penis after zipping of urethral fold
Perineal body?
Fibromuscular tissue between urogenital and anal triangle
Blood supply to male gonad
Testicular artery
Vein on surface of penis
Deep dorsal vein draining the shaft into the internal pudendal vein
Hormone for sexual dimorphism
Y
Progenitor of tubercle swellings
Testes
Progenitor of Genital tubercle enlarges
Glans penis
Urogenital fold becomes…
Urethra
Urogenital groove
Shaft of penis
