Male Reproductive System Flashcards
A Ureters B Seminal vesicles C Bladder D Prostate gland E Vas deferens F Penis G Glans penis H Testis I Epididymis
What are the 3 parts of the male urethra?
prostatic urethra
membranous urethra
spongy (or penile) urethra
Testis vs ovary development
TESTIS
Medullary cords develop
NO cortical cords
Thick tunica albuginea
OVARY
Medullary cords REGRESS
Cortical cords develop
NO tunica albuginea
Where do primordial germ cells migrate?
Dorsal mesentery of hindgut then collect in posterior abdominal wall creating genital ridge
What do medullary cords develop into?
Seminiferous tubules
What do medullary cords drain into?
Rete testis
What are examples of remnants left of regressed Mullerian ducts in testes?
Utriculus prostaticus
Appendix testis
What is the appendix epididymis?
Remnant of mesonephric duct
Describe the muscles of the anterior abdominal wall
Anterior abdominal wall has 2 straight muscles running down from costal cartilages of 5th, 6th, 7th ribs down to pubic bone and pubic symphysis
2 rectus abdominal muscles side by side
Lateral musculature: external oblique muscle, internal oblique muscle, transversus abdominis muscle
What are aponeuroses?
Tendons of lateral abdominal muscles (internal, external oblique and transsversus abdominis) become stretched out like flat sheets called aponeuroses
What is the linea alba
Aponeurosis of internal oblique muscle splits at rectus abdominal muscle into anterior and posterior- fuses with other lateral abdominal muscle tendons in midline LINEA LABA
What is different about tendons below the umbilicus region?
All 3 tendon sheets from lateral abdominal muscles pass anterior to rectus sheath so ONLY ANTERIOR SHEATH below umbilicus
The arcuate line separates this change
Where is the neurovascular plane?
Neurovascular plane between internal oblique muscle and transversus abdominis muscle
Where anesthesiologist injects
What is the inguinal ligament?
Curled edge of external oblique
Nerve supply of external oblique muscle
T7-T12 thoracic spinal nerves
Where does internal oblique arise and where do its fibres go?
Fibres of internal oblique run upwards and medially
Arises from medial half of iliac crest and lateral 2/3 of inguinal ligament
Arises posteriorly from thoracolumbar fassure
Fibres insert onto costal margin
Lower fibres arch over inguinal canal
What 2 muscles form the conjoined tendon?
Internal oblique and transversus abdominis
Rectus abdominis muscle runs through which ribs?
5, 6, 7
Transverse abdominis muscle
Fibres run transversely
Arise from medial half of iliac crest and lateral half of inguinal ligament
Also arises from thoracolumbar fassure posteriorly, and costal cartilages of the lower 6 ribs
Arching fibres over spermatic cord forming conjoined tendon with internal oblique
What artery running through rectus abdominis is important regarding identifying hernias?
Inferior epigastric artery in rectus abdominis, branch of external iliac artery
Marks medial border of deep inguinal ring, key in identifying direct vs indirect inguinal hernia
Where does superior epigastric artery arise from?
Internal thoracic, which comes from subclavian
In aortic occlusion, blood destined for upper body can be diverted through superior epigastric, inferior epigastric, external iliac, to femoral arteries and supply lower limb
What is the inguinal canal?
Oblique intramuscular slit 4-5cm long passing through layers of anterior abdominal wall from deep inguinal ring through superficial inguinal ring
This is pathway of descending testis as it descends into scrotum
What is this structure?
Deep inguinal ring
Indirect hernia vs direct hernia
Indirect passes through ring in canal through superficial ring into scrotum, lateral to epigastric artery
Direct just pushes conjoined muscles forwards, medial to inferior epigastric artery
What layers does the inguinal canal pass through?
Parietal peritoneum Transversalis fascia Transversus abdominus muscle Internal oblique Aponeurosis of external oblique
What nerve is within the neurovascular plane?
Ilioinguinal nerve with L1 fibres supplying tendon (conjoined one)
What is the gubernaculum?
Fibrous cord connected to testis to base of what will become scrotum in foetus
Pulls it down to descend by the time baby is born
What is the protrusion of parietal peritoneum in male foetus around gubernaculum testis?
Processus vaginalis- where testis pushes into
Area then obliterates once testes descended but if it doesn’t predisposed to inguinal hernias
Protrusion of processus vaginalis takes with it all muscles except for?
Transversus abdominis muscle, doesn’t reach medially enough
What is the nervous supply of the cremasteric fascia and muscle?
Genital branch of genitofemoral nerve
What is a hydrocele?
Collection of fluid around testis, can be predisposed to it if vaginalis is not obliterated
Clinical sign is transillumination (red)
When should the testes have descended in place in scrotum?
32 weeks gestation
What happens if testes don’t descend?
Cryptorchidism (can mean subfertility or malignancy) needs operating
Pubic tubercle and hernias
Indirect inguinal- above medial pubic tubercle (more common in men)
Femoral- below and lateral to pubic tubercle (more common in women)
Arterial blood supply for testes and epididymis
Paired testicular arteries arise from abdominal aorta at L2, pass into scrotum via inguinal canal in spermatic cord
What 3 arteries are in the spermatic cord?
Testicular arteries
Cremasteric artery
Artery of vas deferens
3 nerves in the spermatic cord
Ilioinguinal nerve
Genitofemoral nerve
Sympathetic nerve fibres
3 tubes in spermatic cord
Lymphatics
Remnants processus vaginalis
Vas deferens
Where does veinous drainage of testes go?
Into pampiniform plexus, drains into testicular veins
right testicular vein: inferior vena cava
left testicular vein: left renal vein
Varicocele
‘bag of worms’ more common on left
(bc obstructed drainage of left gonadal vein)
an enlargement of the veins within the loose bag of skin that holds the testicles (scrotum). A varicocele is similar to a varicose vein you might see in your leg. Varicoceles are a common cause of low sperm production and decreased sperm quality, which can cause infertility.
Where do lymphatics of testes drain?
Testes are originally retroperitoneal organs, the lymphatic drainage is to the lumbar and para-aortic nodes, along the lumbar vertebrae.
This is in contrast to the scrotum, which drains into the nearby superficial inguinal nodes.
3 coverings of spermatic cord?
external spermatic fascia
cremaster muscle
internal spermatic fascia
Layers of scrotum
Some Damn Englishman Call It A Testis
Skin of scrotum Dartos muscle External spermatic fascia Cremaster muscle Internal spermatic fascia Albuginea (tunica) Testis
Blood supply of prostate gland
Branches of inferior vesical artery
What are the seminal vesicles?
a pair of glands that produce many of the constituent ingredients of semen. They ultimately provide around 70% of the total volume of semen (seminal fluid).
located between the bladder fundus and the rectum (separated from the latter by the rectovesicle pouch and the rectoprostatic fascia).
Vas deferens combine with the duct of the seminal vesicles to form the ejaculatory duct, which subsequently drains into the prostatic urethra.
Where does the 30% rest of ejaculate come from?
Bulbourethral glands
Prostate gland pt 1
Ejaculatory ducts pierce the posterior surface & pass obliquely through the gland to open into prostatic urethra.
Prostate has a thin (true) capsule but is, also, enclosed in sheath of pelvic fascia (false capsule) with the prostatic veins in between.
Glandular tissue is embedded in a fibro-muscular stroma.
Majority of glandular tissue lies in posterior & lateral parts.
Prostatic urethra (3cm) divides gland into Rt & Lt halves.
Gland divided into ‘peripheral zone’ (70%), ‘central zone’ (25%) and ‘transition zone’ (5%). (Previously, divided into lobes).
The ‘median’ lobe lies post posterior to urethra, above ejaculatory ducts, with bladder trigone, superiorly.
Wedge shaped central zone forms the base of the gland and surrounds the ejaculatory ducts. Apex at ‘verumontanum’ (seminal colliculus).
Peripheral zone surrounds the central posteriorly & inferiorly and forms lower part of the gland.
Prostate gland pt 2
The transitional zone surrounds pre-prostatic urethra and its ducts open into the seminal colliculus (verumontanum).
Rapid enlargement at puberty and gradual hypertrophy with age – benign prostatic hypertrophy (BPH).
50%, 70% & 90% of men affected by age 50, 70 and 90yrs resp.
BPH most marked in transitional zone, compressing the peripheral zone.
BPH being a common cause of urethral obstruction.
Peripheral zone commonest site for malignancy.
Blood supply: superior & inferior vesical arteries (from int. iliac a.)
Veins correspond to arteries, some draining to lateral sacral veins and thence to internal vertebral venous plexus.
Latter is important in metastatic cancer of prostate.
Lymphatics follow arterial supply.
Nerve supply: Inf. hypogastric plexus. Parasympathetic → glands & sympathetic →muscle to empty glands at ejacn.
Embryological development of external genitalia
During 3rd week of development ‘cloacal folds’ develop.
Cranially these folds unite to form the ‘genital tubercle’.
Caudally, the folds are subdivided into anterior (urethral) folds and posterior (anal) folds.
‘Genital swellings’ then develop on either side of the urethral folds which will become the ‘scrotal swellings’
After 6 weeks, the external genitalia are indistinguishable.
Under the influence of male androgens, there is a rapid elongation of the genital tubercle which becomes the ‘phallus’.
This elongation extends the urethral folds, anteriorly, and forms the lateral walls of the ‘urethral groove’.
By 12 weeks the urethral folds close and form the ‘penile urethra’.
Most distal part of urethra formed by an ingrowth into the glans.
Structure of penis
The penis has a root and a body
The root consists of:
- Central ‘bulb’ becomes the corpus spongiosum
- Crura on each side become the corpora cavernosa
The anterior part of the corpus spongiosum
expands to form the glans penis
The corpora cavernosa and the corpus
spongiosum join to form the body of the penis
Identify the nerves
Ilioinguinal and genitofemoral supply skin over scrotum and penis
Penis blood supply
Blood supply: 3 pairs of arteries from internal pudendal a.
(1) ‘deep a. of penis’ – supplies c. cavernosum (2) ‘bulbourethral’ – supplies c. spongiosum/glans
(3) ‘dorsal a. – supplies skin and glans
Skin of penis receives supply from sup. & deep pudendal aa.
