10. Male pelvic viscera Flashcards
Male pelvic viscera, anterior to posterior?
Hladder with prostate and urethra, seminal vesicles (and ejaculatory ducts), rectum and anal canal
Bladder fills by its _____ muscle relaxing, empties by its ______
Fills by its detrusor muscle relaxing, empties by its contraction
Contents of the perineum?
Anteriorly: Genitalia and urethra
Posteriorly: Anal canal and ischio-anal fossae
The side walls and floor of the pelvis are in contact with …..
the central, pelvic viscera i.e. bladder and prostate
Location of bladder apex?
At upper aspect of pubic symphysis (5-7cm above when full)
Median umbilical ligament (remnant of embryonic urachus) extends from apex
Surfaces of the bladder?
Postero-superior
Infero-lateral x 2
Base (trigone)
How is ureteric reflux prevented anatomically?
The ureters pass through the bladder wall obliquely, creating a flap valve that prevents urine that is in the bladder from backing up and returning into the ureter (ureteric reflux)
Pressure of urine in the full bladder, forcing the ureters closed
Composition of bladder wall?
Formed by detrusor muscle
Lined by transitional epithelium
What does the male have to prevent semen backflow into bladder?
Proprostatic, internal spincter
What aspect of the female anatomy contributes to urinary continence?
In the female the bladder neck is above the pelvic floor, so that pressure of pelvic organs, as well as levator ani contribute to urinary continence
What structures provide support to the bladder?
Fibromuscular and fascial condensations from bladder, prostate and urethra to pubis, lateral pelvic walls, rectum and sacrum support the bladder
e.g. puboprostatic (male) and pubovesical (female) ligaments
Peritoneum at apex….
NO
Bladder pouches?
Rectovesical (or vesico-uterine and recto-uterine in female)
Suprapubic cathater when?
Safe when bladder has distended up against anterior abdominal wall
Male bladder relations
Superior: Peritoneum, ileum, sigmoid
Base: Rectovesical pouch and septum, rectum, vas deferens, seminal vesicle
Vascular supply of the bladder?
Arteries:
- Ant trunk from Internal iliac
- Superical vesical
- Inferior vesical (or vaginal in females)
Veins:
-Plexus on infero-lateral surface of the bladder.
–> Drains directly to internal iliac vein
(Also drains to the prostatic plexus that drains to internal iliac vein but communicates with the internal vertebral venous plexus)
Lymph drainage of the bladder?
3 plexuses: Mucosa, muscle and serosa
Mainly to the external iliac artery
Bladder nerve supply:
- From where?
- Parasympathetic?
- Sympathetic?
From where?
From anterior part of the Pelvic (or inferior hypogastric) Plexus, that passes the rectum to reach the bladder (Surgical risk)
ParaS:
Detrusor has profuse, mainly p’symp. nerve supply (both afferent and efferent) derived from the Pelvic Splanchnic Nerves (S2, 3, 4) that reach detrusor via the Pelvic Plexus
Symp:
Symp. supply to Preprostatic (Internal) Sphincter as well as some to detrusor (to function synergistically with P’symp.)
Derived from T12, L1, 2, then via Pelvic Plexus
Two options for catheters>
Suprapubic
Urethrally
Presentation of “Injury to the bladder and urethra in particular may lead to urinary extravasation “trapped” by Scarpa’s and Colles’, perineal fascia”?
This fascial layer is shown in purple below and limits the spread of urine and bruising to the lower abdomen, upper thighs, penis and scrotum, but no further posteriorly as Colles’, perineal fascia fuses to the Perineal Body
First part of male urethra?
Preprostatic:
- With internal/genital/prepostatic sphincter
- From bladder neck to upper aspect of verumontanum
- Surrounded by smooth muscle from bladder wall that passes into urethra and also into prostaste
2nd part of male urethra?
Prostatic
- receiving ejaculatory duct opening into prostatic sinuses
- urethral crest causes crescentic section
- Verumontanum with utricle and ejaculatory ducts either side
3rd part of male urethra?
Membraneous surrounded by external sphincter
4th part of male urethra?
Spongy in bulb of penis and then corpus spongiosum
Prostate function?
Genital (not urinary) function Slightly acid seminal secretion: -Acid phosphatase -Amylase -Prostate specific antigen (PASA) -Fibrinolysin
Structure of prostate
Fibromuscular and glandular
Upside-down pyramid
In tough capsule
Supported by puboprostatic ligaments
Surfaces of prostate?
Base
Apex
Posterior: To denonvillier’s fascia and rectum
Anterior: To pubic symphysis and arch
2 x inferolateral surfaces to pelvic floor
Lobes of the prostate?
Lobes only in foetus, 2 lateral and a median may be described in adult. The anterior part of the gland is fibromuscular only
Zones of the prostate?
- Transition 5%, around urethra, ant. to ejaculatory ducts BPH (**benign prostatic hypertrophy)
- Central 25%, behind transition, contains ejaculatory ducts
- Peripheral 70%, around transition and central (**Carcinoma)
Position and role of the seminal vesicals?
The left and right Seminal Vesicles (glands) lie just above the prostate gland, sandwiched between the bladder and rectum. They secrete seminal fluid to nourish sperm.
Formation of the ejaculatory duct?
The dilated, ampullary end of the vas unites with the duct from the seminal vesicle to form the Ejaculatory Duct that passes through the prostate to enter the urethra.
Prostate and proximal urethra lymph drainage?
Mainly to internal iliac nodes
Requirement for innervation of urethra and prostate?
Require:
- Somatic motor for control of striated muscle – ext. sphincter
- Autonomic both sympathetic and parasympathetic
- Sensation
Where is the nerve supply of the urethra and prostate derived from?
S2,3,4
Somatic motor and sensory: From pudendal nerve and its perineal branches
Parasympathetic: From pelvic splanchnics to pelvic plexuses
Sympathetic: From L1 and L2 via superior hypogastric plexus to pelvic plexus
Action of sympathetic stimulation of preprostatic sphincter?
Shuts it for ejaculation
3 stages of micturition?
1. Storage Parasympathetic to detrusor “switched off” in spinal cord to allow bladder to relax and fill Usual volume (male) about 400 ml, if reach 500 ml – pain in lower abdomen and perineum
- “Full” causes desire to micturate
Afferents (sensory) to spinal cord, then “M” Centre in pons – stimulates preganglionic, parasympathetic neurones at S 2, 3, 4 - Void
1y neurones stimulate 2y neurones in bladder wall ganglia, causing detrusor contraction
Simultaneous relaxation of levator ani (pelvic floor) and external urethral sphincter (striated muscle) – S 2, 3, 4 (pudendal nerve) and contraction of abdo. wall; sensation of urine in urethra maintains the reflex
What is the autonomic stretch reflex?
prevails in the untrained infant so that the bladder empties automatically when full
How is the “full” sensation of the bladder detected and responded to particularly in infancy?
When full (usual volume of male about 400 ml) stretch receptors send signals via the parasympathetic pelvic splanchnics (afferents) to cord segments S 2, 3, 4 where they trigger reflexes in the parasympathetic efferents (pelvic splanchnics to pelvic plexus and then to bladder wall) to cause detrusor (bladder) contraction AUTONOMMIC STRETCH REFLEX
Effect of training on on the autonomic stretch reflex of the bladder?
With training, afferents (sensory) ascend up the spinal cord to trigger cortical inhibition in the frontal lobe. This superimposes cortical control on the “M” (micturition) Centre in the pons that in turn (via reticulospinal and corticospinal pathways) usually controls or stimulates preganglionic, parasympathetic neurones at S 2, 3, 4 cord segments
Main location of BPH
Transition 5% of the prostate, around urethra, ant. to ejaculatory ducts BPH (**benign prostatic hypertrophy)
Main location of the carcinoma of the prostate
- Peripheral 70%, around transition and central (**Carcinoma)
Vascular supply of the prostate and urethra in males?
From inferior vesical to prostate gland and proximal urethra.
Internal pudendal also to perineum
Venous drainage to vesical and prostatic plexuses, which drain to internal iliac vein.
There are communications with the valveless veins of the vertebral plexuses (Batson) facilitating tumour spread
Vascular supply of the urethra in the females?
Utero-vaginal and internal pudendal arteres
Venous drainage to veins equivalent to the arterial supply – vaginal and int. pudendal veins
Which clinical scenerios result in detrusor control returning to automatic, infant reflex?
Cord transection above S2
Loss of cortical control following CVA
What clinical scenario results in a paralysed detrusor muscle and the bladder distending until there is overflow incontinence?
Destruction of sacral segments 2,3,4
