Anatomy - Genitourinary and Renal systems Flashcards
What is the inguinal canal?
- oblique passageway through muscles of anterior abdominal wall
Where is the inguinal canal?
- superior to medial half of inguinal ligament
- passes through each layer of abdominal wall as it travels medially and inferiorly (starting at transversalis fascia deep and laterally and finishing with the external oblique aponeurosis superficially and medially)
How long it the inguinal canal?
~5cm in an adult
Where does the inguinal canal extend from?
- deep inguinal ring to superficial inguinal ring
What is the deep inguinal ring?
- an aperture in the transversalis fascia
What is the superficial inguinal ring?
- an aperture in the external oblique aponeurosis
Anterior border of inguinal canal
- external oblique aponeurosis
- laterally only (internal oblique aponeurosis)
Posterior border of inguinal canal
- transversalis fascia
- medially only (medial fibres of aponeuroses of the internal oblique and transversus abdominis)
What is the conjoint tendon?
fusion of aponeuroses of transversus abdominis and internal oblique
Roof of the inguinal canal
- transversalis fascia
- arching fibres of internal oblique and transversus abdominis
Floor of inguinal canal
- inguinal ligament (rolled-up lower border of external oblique aponeuroses)
What are the contents of the female inguinal canal?
- round ligament of the uterus
- ilioguinal nerve
- genital branch of genitofemoral nerve
What are the contents of the male inguinal canal?
- contents and including spermatic cord
- ilioinguinal nerve
Contents of the spermatic cord
- two nerves
- three arteries
- three fascial layers
- four other structures
What are the two nerves in the spermatic cord?
- genital branch of genitofemoral nerve
- sympathetic nerve fibres
What are the three arteries in the spermatic cord?
- testicular artery
- cremasteric artery
- artery to the vas deferens
What are the three fascial layers in the spermatic cord?
- external spermatic fascia
- cremester spermatic fascia
- internal spermatic fascia
What is the external spermatic fascia derived from?
- external oblique aponeuroses
What is the cremaster spermatic fascia derived from?
- internal oblique muscle
What is the internal spermatic fascia derived from?
- transversalis fascia
What are the four other structures in the spermatic cord?
- pampiniform venous plexus
- lymphatics
- vas deferens
- processus vaginalis
Where is the processes vaginalis derived from?
- the peritoneum
What is a hernia?
- an abnormal profusion of tissues or organs from one region into another through an opening or defect
When may a hernia of the abdominal wall occur?
- if the muscles are weak or have been incised during surgery
What is an inguinal hernia?
- a protrusion of abdominal contents (normally part of the greater omentum or loops of small intestine
True or false? Inguinal hernias are indirect or direct
true - can be either
Describe an indirect hernia
- intra-abdominal contents are forced through the deep inguinal ring and into the canal
- abdominal contents may even be forced along the canal and through the superficial ring
Where may an indirect hernia extend into?
- scrotum in males
- labia majora in females
Direct or indirect hernias are common?
indirect - they are also more likely to get stuck in the canal and become ‘irreducible’
Clinical relevance of indirect hernia
- herniated tissue can ‘strangulate’ and become ischaemic
- surgical emergency
Describe a direct hernia
- intra-abdominal contents are forced through the posterior wall of inguinal canal and directly through the superficial ring
- herniated contents do no pass through the deep inguinal ring in direct inguinal hernias
Which hernia is easier to reduce?
direct hernia
What is the scrotal skin?
- thin, wrinkled and more darkly pigmented than skin elsewhere
Dartos
- a thin involuntary muscle underneath the skin
What is found underneath the skin?
- a thin layer of superficial fascia and dartos
- the superficial fascia extends between the testicles to form a septum dividing the scrotum into right and left halves
What does each half of the scrotum contain?
- a testes
- epididymis
- a lower part of the spermatic cord
What are the testes?
- male reproductive organs
- produce sperms
- secrete sex hormone testosterone
Describe the testes
- ovoid structures
- covered by same three layers of spermatic fascia that cover the spermatic cord
- partially surrounded by a sac derived from the peritoneum: Tunica Vaginalis
What is the epididymis?
- a coiled tube lying along the posterior border of each testis
- has an expanded head superiorly, a body and a pointed tail lying at the lower pole of the testis
What is formed in the testis?
- spermatazoa
Where is spermatozoa stored and what does it travel with?
- in the epididymis
- travels with the testicular vessels in the spermatic cord
Where do the testicular arteries arise from?
- they are a direct branch of the abdominal aorta
Where does the venous blood from the testis and epididymas go?
- it enters the pampiniform venous plexus
What does the pampiniform venous plexus form?
- the testicular vein
What does the right testicualr vein join and enter?
- the inferior vena cava
What does the left testicular vein join and enter?
- left renal vein
Name 5 examples of scrotal swellings
- hydrocoele
- varicocele
- epididymo-orchitis
- testicular torsion
- indirect inguinal hernia
Hydrocoele
- painless swelling caused by accumulation of peritoneal fluid between the layers of tunica vaginalis around the testis
- when a light is shone through a hydrocoele it can be seen from the other side
- this is called transillumination
Varicocoele
- abnormal dilation of the pampiniform venous plexus
- described as feeling like a ‘bag of worms’ on palpation (due to dilated veins)
- more common on the left side, due to the fact that the left testicular vein drains into the left renal vein before it drains into the inferior vena cava
- because of this, development of a left-sided varicocele often warrants intra-abdominal investigation to exclude a tumour that may be obstructing its venous drainage
Epididymo-orchitis
- painful inflammation of the epididymas and testis
- epididymo-orchitis in a younger patient is often caused by a sexually transmitted infection such as chlamydia or gonorrhoea whereas in an older patient it is more commonly caused by a urinary tract infection
Testicular torsion
- twisting of the testis on the spermatic cord
- this can lead to ischaemia of testis and is a surgical emergency
- if left untreated, it can lead to necrosis and loss of the affected testis
- torsion is very painful
Testicular cancer
- less common
- prognosis is excellent if detected and trated early, usually with surgery to remove testis and a length of cord (orchidectomy) with chemotherapy or radiotherapy if required
- testicular cancer metastasizes first to the para-aortic or retroperitoneal lymph nodes
Cryptochidism (undescended testis)
- during fetal development the testes form in the abdomen
- descend through the inguinal canal to reach the scrotum before birth
- if this fails to occur the infant is born with one or both testes absent from the scrotum, and the affected testis will be stuck somewhere along the path of descent
- spermatogenesis is optimal just below core body temperature, the testes will only function correctly if they are in the scrotum
- there is an increased risk of testicular cancer if the undescended testis is left inside the abdomen
- therefore, undescended testes are often brouht into the scrotum surgically
Vasectomy
- a means of male sterilisation
- relatively uncomplicated surgical procedure where the scrotum is incised and the vasa deferentia are located on each side and separated, before ligating, cauterising or clamping each end
- this prevents the passage os sperm from the testes
What is the Penis made up of?
3 cylinders of erectile tissue:
- 2 corpora cavernosa dorsally
- 1 corpus spongiosum ventrally
They are enclosed within the deep fascia of the penis
What is the name of the deep fascia of the penis in which the 3 cylinders are enclosed in?
Buck’s fascia
What is the end of the penis called?
- the glans (it is an expansion of the corpus spongiosum)
What does the penile urethra also carry?
- urine
- semen
Where does the penile urethra lie within?
- the corpus spongiosum
The urethra approaches the end of the penis and opens via…
the external urethral meatus
Describe the arterial supply to the penis
- penile arteries
- these are a branch of the internal pudendal artereis (which are a branch off the internal iliac arteries)
Innervation of the penis
- nerve supply: S2-S4
- general sensation and sympathetic innervation are carried by dorsal nerve of penis (branch of pudendal nerve)
- parasympathetic: arise from the peri-prostatic nerve plexus
What are the parasympathetic nerves in the penis reponsible for?
- causing erection by dilating the arteries of the corpora
What are primarily responsible for the increase in size and rigidity of the penis during erection?
- the corpora cavernosa
- during sexual arousal arterial blood flow into corpora increases so it becomes engorged with blood
- corpus spongiosum becomes engorged also but not to the same extent
What is the main role of the corpora spongiosum during erection?
- prevent the urethra from being compressed (which would prevent ejaculation)
Erectile dysfunction
- inability to acheive/maintain erection during sexual acitvity
- common and will affect most males at some point
- problem with blood flow, nerve pathays and relfexes and pschological arousal can cause this
- management: identify cause and treating that or using medications e.g. slidenafil which increase blood flow into the corpora of the penis
Where do the adrenal glands lie?
- close to the upper pole of each kidney
- right: behind the liver and IVC
- left: behind the stomach and pancreas
What are the three arteries that supply the adrenal glands?
- superior adrenal artery
- middle adrenal artery
- inferior adrenal artery
What is the superior adrenal artery a branch of?
- inferior phrenic artery
What is the middle adrenal artery a branch of?
- abdominal aorta
What is the inferior adrenal artery a branch of?
- renal artery
Venous drainage of the adrenal glands
- by a single vein on each side
- right adrenal vein directly drains into the IVC
- left first into left renal vein and then joins IVC
What are the two parts of the adrenal gland?
- outer cortex
- inner medulla
What does the outer cortex of the adrenal glands produce?
- steroid hormones e.g. cortisol, aldosterone and testosterone
What does the inner medulla of the adrenal glands produce?
- adrenaline
Phaeochromocytoma
- rare hormone-producing tumour of adrenal medulla
- secretes excess adrenaline and can cause signs related to hyperactivity of the sympathetic nervous system e.g. hypertenison, tachycardia and excessive sweating
Dimensions of a regular kidney
- 11cm long
- 7 cm wide
- 4cm thick
True or false? the kidneys are both extra-peritoneal and retroperitoneal
true
Describe the positions of the kidneys
- one on either side of the upper lumbar vertebrae
What are the kidneys embedded and then covered in?
- perinephric fat
- this is covered by renal fascia
- there is a further layer of perinphric fat outside the renal fascia
Where is the renal hilum and what does it contain?
- medial border of the kidneys
- renal vessels, nerves, lymphatics and ureter enter/leave the kidney
What are the left/right renal arteries branches of?
abdominal aorta
Where do the left/right renal veins directly drain into?
IVC
Internal compsure of the kidneys
- cortex, medulla and calyces
True or false? The medulla is arranged into pyramids
true
What are the functional units of the kidneys (nephrons) responsible for?
- filtering the blood
- reabsorbing water and solutes
- secreting and excreting waste products as urine
What parts of the nephron are in the cortex?
- glomeruli
- bowman’s capsule
- PCT
- DCT
- part of the collecting duct
What parts of the nephron is in the pyramids?
- loop of henle
- rest of the collecting duct
Where does urine travel down from the collecting ducts to?
- renal papilla (apex of the pyramid) where it enters a minor calyx
- minor calyces merge to form the renal pelvis which is continuous with the ureter
Purpose of the ureter (narrow tubes with muscular walls)
carry urine to the bladder via peristalsis
Where does the ureter run?
- anterior to psoas major on posterior abdominal wall
- cross the pelvic brim to enter the pelvis
- enter the bladder on its inferomedial aspect
What are Kidney (ureteric) stones made from and what are the risk factors for developing them?
- calcium oxalate
- risk factors: high urine calcium levels, dehydration, obesity and certain medications
Typical presentation of an obstructing kidney stone
- excruciating, pulsatile pain felt from loin to groin
- due to the pain fibres supplying ureter originate from T12-L2
- pain is referred and felt in the T12-L2 dermatomes
What occurs if flow of urine from kidneys is obstructed?
- kidney will fill with urine and swell (hydronephrosis)
- this can injure the kidney and may also lead to infection
The ureter narrows in three regions where it is likely for stones to get stuck. These regions are…
- pelvic-ureteric junction (PUJ) - between the renal pelvis and ureter
- pelvic brim - where ureter runs over pelvic brim (anterior to iliac artery)
- vesicle-ureteric junction (VUJ) - where ureter joins the bladder
Urinary Tract Infection (UTIs)
- almost always caused by bacteria entering the urinary bladder via urethra
- more common in females is urethra is shorter
- infection of urinary bladder is called cystitis
- symptoms: burning pain on passing urine and sensation of having to pass urine more frequently
- pyelonephritis is a more serious infection
Pyelonephritis
- requires intravenous antibiotics
- symptoms: fever, flank pain and nausea and vomiting plus other UTI symptoms