Lecture 20: anatomy of the renal system and male reproductive organs Flashcards
What covers the retroperitoneal structures of the abdomen?
The posterior parietal peritoneum
See figure
Paired branches of the abdominal aorta
Inferior phrenic
Suprarenal
Renal
Lumbar
Ovarian/testicular
Common iliac
Unpaired branches of abdominal aorta
1) Celiac trunk
2) Superior mesenteric
3) Inferior mesenteric
4) Median sacral
See figure
Venous drainage of abdomen
Veins follow arteries and collect in vena cava
Except venous drainage from digestive tract and spleen : portal vein
Where do the lymph nodes in the retroperitoneal space collect lymph from?
Lymph collects in the cysterna chill, just inferior to the diaphragm
It then ascends into the thoracic duct, which empties into the left venous angle
See figure
What is the importance of the lymph system in the retroperitoneal space?
Lymphatic disease
Cancer staging
Lipids from digestion are transported by the lymph
What are the 3 sources of blood supply to the adrenal (suprarenal) glands?
1) Inferior phrenic arteries
2) Abdominal aorta
3) Renal arteries
See figure
What does the cortex of the adrenal gland produce?
Glucocorticoids (cortisol)
Mineralocorticoids (aldosterone)
Weak androgens (dehydroepi-androsterone)
See figure
What does the medulla of the adrenal gland produce?
Catecholamines (adrenaline/epinephrine and some noradrenaline/norepinephrine)
What is the only source of androgens in females?
The cortex of the adrenal glands
What are the urinary organs?
Kidney
Ureter
Bladder
Urethra
What structures are in the hilum of the kidney?
Renal artery (s)
Renal vein
Ureter
See figure
How to know if you’re looking at the anterior or the posterior side of a kidney?
Posterior side has the connection to the ureter
What protects the kidney?
Renal fascia and fat capsule
See figure
Where are the openings of the capsule surrounding the kidneys?
Open medially (blood vessels) and caudally (ureter)
What is the significance of the proximity of the kidney to the nerves of the lumbar plexus?
Diseases of the kidney may cause pain in the groin (ilioinguinal nerve)
Functions of the kidney
Blood filtration (glomerulus)
Reabsorption
Excretion
Production and secretion of renin, erythropoietin (EPO) and 1,25-(OH)2 vitamin D3
Function of the renal pelvis
Collects urine from the renal papillae and connects to the ureter
Significance of EPO in renal failure
Patients with renal failure are anemic over time
Longitudinal cross section of the kidney - parts
See figure
Renal papillae
Major calyx
Renal cortex
Renal pyramid
Renal column
Minor calyx
Renal pelvis
Renal hilum
Structure and location of the ureter?
Retroperitoneal muscular tube of 20-30 cm of length
3 layers of smooth muscle facilitate peristalsis
Crosses iliac vessels anteriorly
Enters urinary bladder at the trigone
Trajectory of ureter in men vs women
In men: lateral and inferior to ductus deference, joins bladder superior to seminal vesicles
In women: crosses beneath the uterine artery - water under the bridge
see figure
Importance of location of ureter in women
Crosses beneath the uterine artery
Uterine artery is ligated in hysterectomy.
Need to be careful not to ligate ureter!!
Where are the three constrictions of the ureter?
1) Exit from the hilum
2) Crossing of iliac blood vessels and pelvic brim
3) Entrance into bladder
See figure
Location of urethra in men vs women
Women: urethra is tightly connected to the anterior wall of the vagina
Men: Prostate surrounds proximal urethra
See figure
Male urethra
Urethra in neck of bladder
Prostatic urethra
Intermediate (membranous) urethra
Spongy (penile) urethra
Navicular fossa
See figures
What is the membranous part of the male urethra sensitive to?
Injury during insertion of urethra catheter
What is the widest part of the male urethra?
Prostatic
What does the prostatic male urethra contain?
Openings of the ejaculatory ducts and of the prostatic ductules
Pathology of prostatic male urethra
Benign prostatic hypertrophy (BPH)
Prostatic urethra can become obstructed by proliferating tissue
Where is the spongy part of the male urethra located?
Within the corpus spongiosum of the penis
How long is the female urethra?
Shorter than male urethra, only 4 cm long
Location of the external urethral orifice in females
In the vestibule
Anterior to the vaginal orifice
How are the female urethra and the vagina connected?
Through connective tissue
Pass together through pelvic diaphragm, perineal membrane and external urethral sphincter
Parts of the urinary bladder
Ureter
Detrusor muscle
Internal urethral sphincter
External urethral sphincter (inurogenital diaphragm)
Membranous urethra
Prostatic urethra
See figure
SNS and PSNS control of bladder
PSNS stimulates detrusor muscle
SNS stimulates external urethral sphincter
What happens to location of bladder when it is full? Clinical significance?
Extends and rises up to 10 cm above pubic symphysis
Pushes bladder’s peritoneal lining further toward umbilicus
Surgical access superior to the pubic symphysis is possible without opening the peritoneal cavity
See figure
What is the space of retzius?
Space between bladder and os pubis
See figure
What covers the top of the bladder fundus and apex?
Parietal peritoneum
Where is the safest spot for a catheter?
The median and paramedic suprapubic area of the anterior abdominal wall
Does not contain vital blood vessels or nerves
See figure
Ultrasound with urinary bladder and catheter
Catheter needs to be clamped to allow filling of the bladder to investigate polyps, tumours or signs of cystitis
See figure
What are the male reproductive organs outside the pelvis?
Testis - male gonad, production of testosterone and spermatozoa
Epididymis - maturation and storage of spermatozoa
Vas deferens - transportation of spermatozoa
Bulbourethral glands - lubrication, accessory sex gland
Penis - copulation
What are the male reproductive organs within the pelvis?
Vas deferens
Prostate gland
Seminal vesicles
What are the accessory sex glands?
Prostate gland
Seminal vesicles
Form the liquid component of ejaculate
What is the role of the testis?
produces spermatozoa (tubuli seminiferi)
produces testosterone (Leydig cells)
What ensheathe the testis and epididymis?
Tunica vaginalis testis
Where are the testis located?
In the scrotum: extraperitoneal
Blood and lymph vessels of the testis? Drainage?
Testicular arteries derive from the abdominal aorta and traverse the inguinal canal
Left testicular vein drains into left renal vein, right one into inferior vena cava
Lymph vessels travel along testicular vessels to drain into pre-aortic lymph nodes (lumbar nodes)
What are the male reproductive organs in the pelvis? Location?
Seminal vesicle
Prostate
Vas deferens
Located beneath the peritoneal lining (extraperitoneal), subperitoneal
Structure and location of vas deferens
Long muscular tube
Connects epididymis to ejaculatory duct
Traverses the inguinal canal
Enlarges to ampulla behind the bladder
Joins seminal vesicle for the ejaculatory duct
What is the largest accessory gland of the male reproductive system? Size?
Prostate
3 x 4 x 2 cm (chestnut size)
Location of prostate
Between bladder and perineal membrane
Where do the prostate’s ducts open?
Prostatic part of male urethra
What is the prostate embedded inside?
A fibromuscular stroma
Contains smooth muscle
How much of the ejaculate volume is composed of prostatic secretions?
20-30% of ejaculate volume
Prostatic secretion characteristics
Acidic (pH 6.4)
Serous
Milky
Content of prostatic secretions
immunoglobulins
acidic phosphatase
proteases
fibrinolytic enzymes
zinc
prostaglandins
citrate (acidic pH!)
spermin (polyamine associated with nucleic acids. Initially thought to only be in semen, but now found in other tissues)
Why are the testis located outside the abdomen?
Temperature control is important for sperm production
Risk of developing testicular cancer increases in undescended testis
What nerves supply the deep arteries of the penis? Importance? Location?
PSNS nerves (pelvic sphlanchnic nerves S2-S4)
Essential for penile affection
Course lateral to the rectum and the prostate
What structures join to form the ejaculatory duct?
The seminal vesicle
Ampulla of vas deferens
Ejaculatory duct then enters urethra
Where does the arterial supply of the prostate originate from?
Inferior vesical artery
See figure
Venous drainage of prostate
Prostate veins drain into the vesicoprostatic plexus which drains into the internal iliac vein.
Parts of penis
Glans
Body
Root
See picture
What are the roots of the penis covered by?
Scrota raphae
What does the penis contain?
2 corpora cavernosa (contain arterial blood)
1 corpus spongiosum surrounding the urethra (contains venous blood, softer, contains urethra)
What is the scrotum?
Pouch of skin and muscle (cremaster muscle)
Homologous to the labia major in women
What does the scrotum contain?
Testis
Epididymis
Blood vessels
Arteries of penis
All arteries are branches of the internal pudendal artery
Veins of penis
Deep dorsal vein drains blood from corpora cavernosa into the prostatic venous plexus
Corpora cavernosa and corpus spongiosum in erection
Both corpora cavernosa lie within a common tunica albuginea: erection is facilitated by fast influx of
arterial blood into the cavernous spaces (deep penile artery)
The corpus spongiosum is a separate erectile body embedding the urethra.
See figure
What are the corpus cavernous formed by?
Both crura of the penile root converge anteriorly to form the corpora cavernousa
What is the corpus spongiosum formed by?
The bulb of the penis continues anteriorly to form the corpus spongiosum and the glans penis
What events occur during penile erection
Parasympathetic stimulation (S2-S4) via pelvic splanchnic nerves (cavernous nerves)
Closes arteriovenous anastomoses
Relaxes smooth muscles in helicine arteries (branches of deep artery of penis)
Arterial blood flows into the cavernous spaces in corpora cavernosa
At the same time, venous return is decreased by the pressure within the tunica albuginea
What compounds increase penile erection?
Inhibitors of cGMP-selective phosphodiesterase-type 5 (PDE5) relax smooth muscles in helicane arteries
See figure
Nerves of the pelvic region
Lumbar plexus: Iliohypogastric nerve Ilioinguinal nerve Genitofemoral nerve Obturator nerve Femoral nerve Lateral cutaneous nerve of the thigh
Sacral plexus: Sciatic nerve Superior gluteal nerve Inferior gluteal nerve Pudenal nerve Posterior cutaneous nerve of the thigh Direct branches to muscles of the pelvis
Autonomic nerves of pelvis
SNS: superior hypogastric plexus, hypogastric nerve, sacral sympathetic trunk
PSNS: pelvic sphlanic nerves
PSNS and SNS: inferior hypogastric plexus
See figure
What are the roles of the somatic nerves of the lumbar and sacral plexus?
Provide motor innervation (to the muscles of the anterolateral abdominal wall, muscles of the lower extremity, gluteal muscles, pelvic floor muscles, muscles of the perineum
Provide sensory (cutaneous) innervation (incl. pain) (to the skin of the anterolateral abdominal wall, skin of the lower extremity, skin of the gluteal region, skin of the perineum, mucosa of the lower urethra, vagina, vestibule, anal canal)
Roles of the autonomic nerves of the pelvis?
Provide motor, secretory sensory innervation to the pelvic viscera
Provide sympathetic innervation (from sacral sympathetic trunk) to the skin of the lower extremity, gluteal region and perineum
Provide parasympathetic innervation (from S2-S4 parasympathetic center) to the smooth muscles of the rectum, to the corpora cavernosa of the penis/clitoris
