WEEK 9 MALE PERINEUM AND PELVIC ORGANS FINISHED Flashcards
What does the male perineum include?
The anal canal, the intermediate and spongy parts of the urethra, and the root of the penis and the scrotum.
What are the 4 parts of the male urethra?
Preprostatic urethra (urethra in the bladder neck) Prostatic urethra Intermediate urethra (membranous) Spongy urethra (penile)
What is the intermediate urethra?
Shortest section of the male urethra (1-2 cm)
Begins at the apex of the prostate and ends at the bulb of the penis.
x
What is the spongy urethra?
x
What is the scrotum? What is it made of?
A cutaneous fibromuscular sac.
Its an out pouching of the anterior abdominal wall.
Contains the testes, epididymides and distal ends of the spermatic cord.
What is the optimal temperature for spermatogenesis?
1.2 degrees lower than core temperature.
What is spermatogenesis? How many are made per day?
Sperm production. >100 million per day.
What is the arterial supply to the scrotum?
Anterior aspect - external pudendal arteries (off femoral)
Posterior aspect - internal pudendal arteries, also branches from the testicular and cremasteric arteries (off inferior epigastricartery (Ext Iliac artery))
What is the innervation of the scrotum?
Anterior aspect - anterior scrotal nerves derived from ilioinguinal (L1) and genitofemoral (L1,L2) nerves
Posterior aspect - Posterior scrotal nerves derived from the superficial perineal nerves and the perineal branch of the posterior femoral cutaneous nerves (S2,S3)
What are the layers of the scrotum? DONT NEED TO LEARN THE DIFFERENT LAYERS, JUST KNOW THAT THERE IS MUSCLES THAT ARE SMOOTH THAT HELP TO REGULATE THE TEMP OF THE TESTES
Skin Superficial fasic and dartos mm External spermatic fascia Cremaster Cremaster fascia Internal spermatic fascia Tunica vaginalis
What is the testes?
A ovoid organ that is suspended in the scrotum by the spermatic cord.
It produces sperms/spermatozoa (male germ cells)
Also produces hormones) principally testosterone
Where in the testes are sperm produces? Which testis is lower (usually)?
In long convoluted seminiferous tubules that are around 70cm long. These are joined by straight tubules to the tete testis. Usually the left is more inferior suspended lower than right
What is each testis covered by?
A tough, fibrous coat - the tunica albuginea which also extends into the testes forming the septa.
What is the tunica vaginalis? What are the 2 layers of this?
A visceral layer that covers the surface of each testis except where the testis attaches to the epididymis and spermatic cord.
A further layer called the parietal layer of the tunica vaginalis, is separated from the visceral layer of the tunica vaginalis by a cavity which contains a small amount of fluid.
What is the arterial supply of the testis?
Testicular arteries - anterolateral aspect of the abdominal aorta just inferior to the renal arteries.
They pass retro-peritoneally (externally/ posterior to the peritoneum)
Arteries anastomose with the artery of the ductus deferens.
What is the purpose of the 2 layers of the tunica vaginalis?
Allows the testis to freely slide past each other
Innervation of the testis?
Testicular plexus on the testicular artery. PNS fibres from the vagus nerve. Sympathetic fibres T10-T11
What is the epididymus? Where is it? What happens in it?
A highly convoluted tubule (7 m long) which connects the testis to the vas deferens.
Lies on posterior surface on the testis.
Sperm pass along the tube over several days during which time they mature.
What happens in the lower part of the epididymus?
Sperm are stored and concentrated until ejaculation
What are sertoli cells? What do they do?
They secrete tubular fluid into the epididymus which move along the sperm.
What part of the epididymus is not covered by the tunica vaginalis?
Posterior margin
What are the 3 parts of the epididymus?
-a head: the superior expanded part that is composed of lobules formed by the coiled ends of 12 -14 efferent ductules
-a body: that consists of the convoluted duct of the epididymis
-a tail: which is continuous with the ductus deferens
(the duct that transports sperm from the epididymis to the ejaculatory duct)
What is the vas deferens also known as/
The ductus deferens
What is the vas deferens? What is it the continuation of? What does it convey? How long is it? Where does it run?
The continuation of the duct of epididymus.
Begins in the tail of the epididymus. Conveys sperm from the epididymus to the ejaculatory duct.
Its 45cm long
It ascends in the spermatic cord, ends by joining the duct of the seminal vesicles to form the ejaculatory duct.
Arterial supply to the Epididymus and vas deferens. Veins and lymph?
Tiny deferential artery, arises from the inferior vesicle artery and terminates by anastomosing with the testicular artery.
Veins accompany arteries
Innervation of the epididymus and vas deferens.
Inferior hypogastric plexus - facilitate the rapid contraction for the expulsion of sperm during ejaculation.
What are the 3 regions of the penis? Which bits are fixed and which are free?
The root, the body and the glans penis. The root is fixed, the body hangs free.
What does glans mean?
Acorn
What is the root of the penis?
The region of the penis attached to the anterior pelvis.
What forms the root of the penis?
- The region of the penis attached to the anterior pelvis
- Consists of crura, bulb, ischiocavernosusand bulbospongiosusmuscles
- Cruraand bulb contain erectile tissue
- Cruraare attached to the corresponding ischialramus
- Bulb of the penis is penetrated superiorly by the urethra
CRURA:
•Crura/ Crus= leg
•Each crusis attached to the corresponding ischialramus.
•Its outer surface is covered by the ischiocavernosusmm
•Converge and lie side by side forming the corpora cavernosa
BULB:
•Found in the midline.
•Traversed by the urethra.
•Covered by the bulbospongiosusmm on the outer surface.
•Continues as the corpus spongiosumin the shaft of the penis
What is the body of the penis? What is it made from?
- Is the free part of the penis, which is pendulous in the flaccid condition
- Apart from a few fibres of the bulbospongiosus and ischiocavernosus, the body has no muscles
- It contains skin, connective tissue, blood and lymphatic vessels as well as the corpora cavernosa and the corpus spongiosum(containing the spongy urethra)
•Consists of three cylindrical bodies of erectile cavernous tissue
-corpora cavernosa (2)
-corpus spongiosum (1)
•These are enclosed in a fibrous capsule called the tunica albuginea, as well as fascia.
- The corpus spongiosum contains the spongy urethra
- The corpora cavernosa are fused with each other at the median plane, except posteriorly where they are separated to form the crura (legs) of the penis
What is the glans penis?
- Distal region of the corpus spongiosumwhich expands to form the glanspenis
- The head of the penis
- The margins of the glansproject beyond the end of the corpora cavernosato form the corona of the glans
- Near the tip of the glansfind the external urethral orifice (meatus), this is the slit like opening of the urethra
- Over part of the glansget a double layer of skin and fascia which is known as the prepuce or the fore skin
What is the suspensory ligament of the penis?
Region of the condensed deep fascia that arises from the anterior surface of the pubic symphysis
It splits and forms a sling that is attached to the deep fascia of the penis at the junction of the root and the body.
What is the fundiform ligament?
•A band of elastic fibres that extend from the linea alba to the pubic symphysis and split to surround the penis before attaching to the fascia of the penis
What is the arterial supply of the penis?
Mainly by the branches of the internal pudendal arteries (branch of the anterior division of the internal iliac artery)
Venous supply to the penis
- Blood from the cavernous spaces is drained by a venous plexus that flows into the deep dorsal vein of the penis.
- It then flows to the prostate venous plexus
- Blood from the superficial coverings drain into the superficial dorsal vein which flows into the superficial external pudendal vein
What is the innervation of the penis?
•S2-4, pudendal nerve and a terminal branch, the dorsal nerve of the penis
•Pelvic plexuses
•Also branches of the ilioinguinal nerve
( L1 ) supply the skin at the root of the penis
What are the seminal vesicles? how long are they? Where do they lie? Do they store semen? What do they do?
- 2 lobulatedvesicles ~ 5 cm long
- Elongated structures that lie between the bladder and the rectum
- Unlike their name suggests they do not store semen
- They secrete a thick fluid that mixes with sperm as they pass into the ejaculatory ducts and urethra, most of the liquid component of semen
- Superior ends are covered with peritoneum
- The duct of the seminal vesicle join the ductusdeferens to form the ejaculatory duct
What is the arterial supply of the seminal vesicles?
Inferior vesicle and middle rectal
What is the innervation of the seminal vesicles?
•Sympathetic
-superior lumbar and hypogastric nerves
•Parasympathetic
-pelvic splanchnic nerves via the inferior hypogastric plexuses
What are the ejaculatory ducts? How long? Where do they arise? Where do they run and what do they open into?
- Is a slender tube that arises by the union of the seminal duct and the ductus deferens
- Approx. 2.5 cm long
- Arise near the neck of the bladder
- Run in anterior inferior direction through the posterior aspect of the prostate
- Open into the prostatic urethra
What is the arterial supply of the ejaculatory ducts?
-deferential arteries which are usually branches of the inferior vesicle arteries
•Venous and lymphatic drainage
- veins join the prostatic and vesicle venous plexuses
- lymphatic vessels drain into the external lymph nodes
What is the innervation of the ejaculatory ducts?
•Derived from the inferior hypogastric plexus
What is the prostate? How long is it? What does it surround? What is it surrounded by?
- Gr“standing before”
- Approx 3 cm long (think “walnut size”)
- Largest accessory gland in the male reproductive system
- 2/3 rds glandular
- 1/3 rd fibromuscular
- Surrounds the prostatic urethra
- Surrounded by a dense fibrous prostatic capsule, which is further surrounded by a prostatic sheath which is continuous with the puboprostaticligaments
What are the surfaces and parts of the prostate? Base Apex Muscular anterior surface Posterior surface Inferolateral surface
- Has a base which is closely related to the neck of the bladder
- An apex which is closely related to the superior aspect of the urethral sphincter and deep perineal mm.s
- A muscular anterior surface, featuring mostly transversely orientated mm fibres continuous with the urethral sphincter, this is separated from the pubic symphysis by retropubic fat in the retropubic space.
- A posterior surface which is closely related to the rectum
- Inferolateral surfaces that are related to levator ani
What is the anterior lobe of the prostate?
lies anterior to the urethra
- fibromuscular, the muscle fibres representing a superior continuation of the urethral sphincter mm
- contains little if any glandular tissue
What is the posterior lobe of the prostate?
- lies posterior to the urethra and inferior to the ejaculatory ducts
- palpable to digital rectal examination
What is the lateral lobe of the prostate?
- on either side of the urethra, forms the major part of the prostate
- contains lots of glandular tissue
What is the median/ middle lobe of the prostate?
- lies between the urethra and the ejaculatory ducts and is closely related to the neck of the bladder
- relates to the trigoneof the bladder
What are prostatic ducts? How many of them are there?
- 20 -30
- Open chiefly into the grooves (the prostatic sinuses) that lie on either side of the seminal colliculus(rounded eminence) on the posterior wall of the prostatic urethra
- Extensive bands of smooth mm, contraction expels the contents, provides propulsive force needed to ejaculate semen.
- Prostatic fluid is a thin milky fluid and it provides approx 20% of the volume of semen
What is the arterial supply for the prostate?
•Prostatic arteries arise from mainly branches of the internal iliac artery
(esp inferior vesicle arteries, also internal pudendal & middle rectal arteries)
Venous and lymphatic drainage
•A plexus of veins forms around the prostate known as prostatic venous plexus
•Found between the fibrous capsule and the prostatic sheath
•The plexus then drains into the internal iliac veins
•Lymphatics chiefly drain to the internal iliac and sacral lymph nodes
What is the innervation for the prostate?
- Parasympathetic nerves arise from the pelvic splanchnic nerves (S2-4)
- Sympathetic fibres from the inferior hypogastric plexus (T12 -L2)
What are the bulbourethral glands? AKA? How big are they? Where do they lie? What is their function?
Cowpers glands
- 2 pea sized glands (1 cm diametre) (2.5 cm duct)
- Lie posterior and laterally to the membranous part of the urethra, beneath the external urethral sphincter
- Ducts pass through the perineal membrane with the urethra and open with tiny apertures into the proximal part of the spongy urethra in the bulb of the penis
- Mucous like secretions enter the urethra during sexual arousal
- Secretions are less than the prostate and seminal vesicles
- Secretions neutralize pH of urine residue, lubricates tip of the penis in preparation for coitus
What is semen? What is is made of? How many sperm per ejaculation?
•Semen consists of a mixture of secretions produced by the testes, seminal vesicles, prostate and bulbourethral glands
- The fluid ejaculated from the penis at sexual climax
- A milky white sticky mixture, includes sperm and accessory gland secretions
- ~ 2-5 ml
- Each ejaculate may contain 300 -500 million sperm
- Contains fluid from the prostate (20% -40%) , seminal vesicles (60%) and bulbourethral glands (Cowpers glands) as well as sperm (
Sperm facts part 1
- Also stimulates reverse peristalsis in the uterus and uterine tubes facilitating movement of sperm
- Relaxin (hormone) and other enzymes in the semen enhance motility
- The semen is alkaline which helps neutralize the acidic environment in the male urethra and female vagina
- Antibiotics destroy certain bacteria
Sperm facts part 2
- Liquid vehicle for sperm, conducive to sperm viability
- Contains fructose, provides sperm with energy
- -provides nearly all the fuel, produced in the seminal vesicles
- Contains prostaglandins which affect the mm of the uterus and may therefore assist transport of sperm
- Decrease the viscosity of mucous guarding the cervix
What is ejaculation? Innervation?
- The propulsion of semen from the male duct system
- The reproductive ducts and access glands contract
- The bladder sphincter muscle contracts, prevents the expulsion of urine and reflux of semen into the bladder
- Sympathetic control
- Erection
- Parasympathetic control
