Anatomy Flashcards
The urinary tract consists of what?
- the anatomical structures through which urine passes from its production to its excretion (removal from the body)
- the kidney; produces urine
- the ureter; drains urine from kidney to bladder
- the bladder; stores / voids urine
- the urethra; excretion of the urine
What does the upper urinary tract consist of?
- the kidneys (right and left)
- the ureters (right and left)
What does the lower urinary tract consists of?
- the bladder (unpaired midline structure)
- the urethra (unpaired midline structure)
An upper urinary tract infection may spread where?
May spread to the kidneys
A lower urinary tract infection involves what?
The urethra and bladder
Where is the urinary tract found?
The abdomen;
- in the retroperitoneum
- kidneys
- the proximal ureters
The pelvis;
- the distal ureters
- the bladder
- the proximal urethra
The perineum;
- the distal urethra
What is found lateral to the kidney?
- most laterally we have layers of muscles
- - anterolaterally is the abdominal wall muscles (external oblique, internal oblique, transversus abdominus)
What is found medial to the kidney?
- hilum of the kidney / root of kidney
- most anterior at the root is the renal vein
- immediately behind that is the renal artery
- inferiorly is the ureter
What is found anterior to the kidney?
- immediately surrounding the kidney is the renal capsule
- then perinephric fat
- then renal / deep fascia of the kidney
- then another layer of fat which is paranephric fat
- then finally the visceral peritoneum
What is the renal capsule?
A tough fibrous tissue that closely encapsulates the kidney all the way around its surface
What is the perinephric and paranephric fat?
- perinephric; liqudiy fatty area immediately surrounding the renal capsule
- paranephric; further away from the kidney
What is found posterior to the kidney?
- posterior abdominal wall muscles
- most posterior is quadratus lumborum
- posteromedial is psoas major (immediately behind kidney)
Where are the kidneys located?
- posterior to their own visceral peritoneum
- enclosed within the renal fat / fascia / capsule
- surrounded by skeletal muscles; muscles of the posterior abdominal wall, muscles of the antero-lateral abdominal wall, muscles of the back
- muscle guarding can protect the kidney from trauma
The kidneys lie?
A) anterior to
B) lateral to
A) anterior to quadratus lumborum
B) lateral to psoas major, also lateral to the lower thoracic / upper lumbar vertebral bodies
Why might the right kidney be found lower than the left kidney?
- due to the size of the liver
- L1-L3 for the right kidney
- T12-L2 for the left kidney
Describe ‘balloting’ the kidneys
- palpate posteriorly within the flank just inferior to the 12th rib
- palpate anteriorly within the RUG
- the liver and spleen lie in contact with the diaphragm superior and the superior poles of the kidneys inferiorly
- so the kidneys move inferiorly on inspiration then superiorly on expiration
- as the patient breathes in the kidneys descend and may be trapped for examination between the palpating hands
- a normal kidney is 12cm long, 6 cm wide, smooth, regular and firm
Name the anatomical relationships of the right kidney
- posterior to the liver (and hepatorenal recess), the 2nd part of the duodenum, the ascending colon and right colic flexure
Name the anatomical relationships of the left kidney
- posterior to the stomach, the tail of the pancreas, the hilum of the spleen and the splenic vessels
What is the most dependent part of the greater sac of the peritoneal cavity in the supine patient?
Hepatorenal recess
What lies anterior tot he renal arteries?
Renal veins
The common iliac arteries are anterior to what?
The common iliac veins
The lymph from the kidneys drain to where?
The lumbar nodes (located around the abdominal aorta and inferior vena cava)
Where does the abdominal aorta bifurcate?
At the level of the umbilicus
What is the arterial ureteric blood supply?
Branches from;
- the renal artery
- the abdominal aorta
- the common iliac artery
- the internal iliac artery
- the vesical (bladder) artery
The lymph from the ureters drains to where?
- the lumbar nodes and the iliac nodes (the latter located around the common, internal and external iliac vessels)
Name examples of the anatomical variation in the renal system?
- bifid renal pelvis, forking of the renal pelvis
- bifid ureter
- retrocaval ureter
- horseshoe kidney
- ectopic kidney down in the pelvis
- solitary kidney
The human medulla contains what?
Renal pyramids
Each pyramid contains what?
Around 50,000 nephrons
What gives the pyramids their striated appearance?
The regularly arranged nephrons (running axially towards the apex of each pyramid)
How does the urine drain from the kidney?
- nephrons collecting duct
- minor calyx
- major calyx
- renal pelvis
- ureter
The diameter of urine drainage ‘tubes’ is increasing until?
- until a constriction at the pelviureteric junction
- the wider renal pelvis becomes the narrower ureter
What is the first constriction site within the renal system?
The pelviureteric junction
Name the anatomical sites of ureteric constriction
- pelivureteric junction
- ureter crossing anterior aspect of the common iliac artery (often crosses the bifurcation)
- ureteric orifice (opening into one corner of the trigone on the floor of the bladder)
Renal calculi can form from what?
- urine calcium salts and obstruct the urinary tract from within
A ureteric obstruction can occur as a result of what?
- internal obstruction; an impacted renal calculus or a blood clot
- external compression; an expanding mass (e.g. a tumour)
How does the ureter respond to obsturction?
- it has smooth muscle in its walls so will respond similarly to the the GI tract
- increase peristalsis proximal to the site of the obstruction in an attempt to remove it (flush it into bladder)
- as peristalsis comes in waves, a patient with ureteric obstruction tends to experience paint that is colicky in nature
What are the consequences of urinary tract obstruction?
- obstructions cause urine to back up in the tract toward the kidneys
- obstructions within the calyces or ureter cause unilateral back pressure of urine
- obstructions within the bladder may cause unilateral or bilateral kidney problems
- obstructiosn to the urethra cause bilateral kidney problems
- urine production will continue until the pressure within the urinary tract exceeds the pressures favouring filtration at the glomerulus
What is renal failure?
Means failure to adequately filter the blood to produce urine
What is hydronephrosis?
- water inside the kidney
- urine back pressure into the calyces compresses the nephrons within the medullary pyramids leading to renal failure
- acute hydronephrosis causes painful stretching of the renal capsule
The ureters pass from the retroperitoneum to where?
- through the false pelvis and into the true pelvis
What is the false pelvis?
- from iliac crests to pelvis inlet
- part of the abdominal caivty
What is the true pelvis?
Pelvic inlet to the pelvic floor
Where is the bladder found?
In the pelvic cavity
Name the pelvic floor muscle
- levator ani
- (pelvic diaphragm)
The pelvic floor is formed by what?
- the bowel shaped pelvic diaphragm
- made up of muscles including levator ani
What are the openings in the pelvic floor for?
- distal parts of alimentary, renal and reproductive tracts to pass through
- from pelvic cavity into peritoneum
What is the perineum?
The shallow compartment between pelvic floor and skin
What passes anteriorly to the common iliac vessels to enter the pelvis?
The pelvic ureters
Describe the route of the pelvic ureters
- anterior to common iliac vessels to enter pelvis
- run anteriorly (along the lateral wall of the pelvis)
- at the level of the ischial spine, they turn medially to enter the posterior aspect of the bladder
- this route is completely sub peritoneal
- the ureters enter the posterior bladder wall in an inferomedial direction
Why do the ureters enter the bladder wall in an inferomedial direction?
Helps prevent reflux of urine back into the ureters when the bladder contracts
The ureter runs inferiorly to what in males and females?
Males;
- inferiorly to the vas deferens
Females;
- inferiorly to the uterine tubes and the uterine artery
The arteries entering the pelvis are mainly branches from what?
The internal iliac artery
What forms the 3 corners of the trigone?
- 2 ureteric orifices
- Internal urethral orifice
What lies inferior to the bladder in the male?
The prostate gland
What are the ureteric orifices?
The opening through which the bladder will receive urine from ureters
What is the name of the opening of from the bladder to the urethra?
The internal urethral orifice
Which muscle forms the main bulk of the bladder wall?
The detrusor muscle
The destrusor muscle fibres encircle what and why?
- encircle the ureteric orifices
- these fibres tighten when the bladder contracts; another mechanism to prevent reflux of urine superiorly into the ureter
Around the neck of the bladder in the male, the detrusor muscle forms what?
- the internal urethral sphincter muscle
- contract during ejaculation to prevent retrograde ejaculation of semen back into the bladder
What is the most anterior organ in the pelvis?
The bladder
- lying posterior the the pubic bone when empty
Describe the relationship between the bladder and the uterus
- the body of the uterus usually lies superior to the bladder in an anteflexed position
- it is separated from the bladder by the uterovesical pouch
- as a result, most of the weight of the uterus is borne by the bladder
The peritoneum covers what surface of the bladder?
The superior surface only
A full bladder can extend out where?
- out of the pelvis
- its superior part lies superior to the pubic bone
- peritoneum still only covers its superior surface
Name the 2 routes of catheterisation
- urethral (more common)
- suprapubic (through anterior abdominal wall and avoiding peritoneal cavity
The female urethra is approx how long?
Approx 4cm long
The male urethra is approx how long?
Approx 20cm long
Sperm is produced where?
Seminiferous tubules of the testes within the scrotum
Sperm is stored where?
Epididymis
Describe the route of sperm
- testes within scrotum
- epididymis
- pass into vas deferns
- will then pass within spermatic cord through the abdominal wall
- then tracks posterior to the bladder where it will join in the seminal gland
- then it passes into ejaculatory duct
- then into prostate gland to join prostatic urethra
- semen and sperm then pass from prostatic urethra to spongy urethra
- then exits via the external urethral orifice
At birth, the scrotum should contain what?
The testes
What is the spermatic cord?
A collection of structures which support the functioning of the testis (testicular artery, testicular vein, vas deferens, lymphatic vessels draining the testis, nerves)
Inside the scrotum, the testes sit within a sac called what?
Tunica vaginalis
Excess fluid within the tunica vaginalis is called what?
A hydrocele
What is the function of the pampiniform venous plexus?
To drain deoxygenated blood from the testis
The testicular arteries arise from where?
The abdominal artery
Where do the left and right testicular veins drain?
- right; drains directly back to the IVC
- left; drains back to the left renal vein
Where is the epididymis palpated?
- at the posterior aspect of the testis
- its proximal end (the head) is located at the posterior aspect of the superior pole of the testis
- the vas deferens is palpated within the spermatic cord; within the scrotum, superior to the testis
What is the function of the prostatic ducts?
Through which the glandular secretions from the prostate drain into the prostatic urethra
Describe the size and position of the prostate gland
- approx ‘walnut sized’
- surrounds the prostatic urethra
- its inferior aspect is in contact with the levator ani muscles
- opening is in the core of the prostatic urethra
The prostate consists of what and what are these?
- zones
- the peripheral zone is the part of the prostate that is felt on digital rectal examination (most cancers arise here)
- central zone
The root of the penis is connected to what?
The ischium
Describe the blood supply to the penis
- via the deep arteries of the penis
- branches of the internal pudendal artery (from the internal iliac)
Describe the blood supply to the scrotum
- via the internal pudendal
- branches from the external iliac artery
Describe the lymph drainage of the penis
- lymph from the scrotum and most of the penis (not the glans) drains to the superficial inguinal lymph nodes found in the superficial fascia in the groin
- lymph from the testis drains to the lumbar nodes around the abdominal aorta
Sensations from the body wall (soma) i.e. our external environment are conveyed to the CNS by what?
Somatic sensory nerve fibres
Sensations from our organs i.e. our internal environment are conveyed to the CNS by what?
The visceral afferent nerve fibres
Motor responses to our body wall are conveyed from the CNS by what?
Somatic motor nerve fibres and stimulate skeletal muscles to contract
Motor responses to our organs are conveyed from the CNS by what?
- sympathetic
- parasympathetic nerve fibres
Ureteric peristalsis and bladder contraction is controlled by what nerve domains?-
Sympathetic / parasympathetic
Urethral sphincter control is controlled by what nerve domains?
- Somatic motor (external sphincter and levator ani )
- sympathetic / parasympatehtic (internal sphincter)
Renal system pain is controlled by what nerve domains?
Visceral afferents
somatic sensory in perineum
The voluntary control of the elimination of urine from the bladder is controlled by what nerve domain?
- sympathetic / parasympathetic
- somatic motor
- visceral afferent
Lumbar and sacral plexus (motor and sensory) is controlled by what nerve domain?
- somatic sensory
- somatic motor
Sympathetic fibres reach the smooth muscle / glands of the body wall within what?
Spinal nerves
Sympathetic fibres reach the smooth muscles / gland of the body (other than body wall) within what?
Splanchic nerve (cardiopulmonary or abdominopelvic)
Describe the route of the presynaptic sympathetic nerve fibres to the kidneys, ureter and bladder?
- leave the spinal cord approx between levels T10 and L2
- enter the sympathetic chains (bilaterally) but do not synapse
- leave the sympathetic chains within abdominopelvic splanchic nerves
- synapse at the abdominal sympathetic ganglia which are located around the abdominal aorta
Describe the route of the post synaptic sympathetic nerve fibres to the kidney, ureters and bladder
- postsynaptic sympathetic nerve fibres pass from the ganglia onto the surface of the arteries which are heading towards the organs they need to innervate
- the collection of nerve fibres found on the outside of the arteries is called a ‘periarterial plexus’
- other nerve fibre types also take part in such plexuses are parasympathetic and visceral afferent nerve fibres (as they are all going to / coming from the same organs)
Pelvic splanchic nerves are what modality?
Exclusive to the parasymapthetic system and are relayed to the organs of the pelvis
Parasympathetic nerve fibres which innervate the kidneys and ureter are carried within what?
The vagus nerves
Parasympathetic nerve fibres which innervate the bladder are carried within what?
The pelvic splanchic nerves
How do somatic motor nerve fibres get from the CNS to the kidneys, ureters and bladder?
- the dont go to any of these structures
- only somatic fibres go to body wall structures
Pain from the kidney is felt where?
- in the loin
- posterior aspect of the flank region, on the affected side
Pain from the bladder is felt where?
Is usually felt in the suprapubic region (midline)
Pain from the perineal part of the urethra is felt where?
Quite localised in the perineum
Pain from a calculus obstructing the ureter can be felt where?
Radiating from loin to groin on the affected side
Visceral afferents from the kidneys run along what to enter the spinal cord where?
- run alongside sympathetic fibres
- enter the spinal cord approx between level T11 and L1
Name differential diagnoses of loin pain
- skin origin (e.g. herpes zoster)
- muscular
- vertebrae
- spinal nerve root compression
- lower lobe pneumonia
Visceral afferents from the ureters run alongside what and enter the spinal cord where?
- run alongside sympathetic fibres
- enter the spinal cord between T11 and L2
Name differentials of groin pain
- hernia (inguinal or femoral)
- lymphadenopathy
- testicular pathology
Visceral afferents from the bladder run alongside what and enter the spinal cord where?
- visceral afferents carrying pain from that part of the bladder which touches the peritoneum run alongside sympathetic fibres
- enter the spinal cord between levels T11-L2
- visceral afferents from the rest of the bladder (that not touching the peritoneum) run alongside the parasympathetic nerve fibres back to the spinal cord levels S2,S3, S4
Name the differential diagnosis of suprapubic pain
- hindgut organs e.g. sigmoid diverticula
- other single, midline organs whose superior aspect touches the peritoneum e.g. uterus
How do visceral afferent and somatic sensory nerve fibres get from the urethra to the CNS?
- visceral afferents from the proximal urethra (i.e. above the levator ani and in the pelvis) run alongside the parasympathetic nerve fibres back to the spinal cord levels S2,S3 ,S4
- somatic sensory nerve fibres from the remaining urethra are carried within the pudendal nerve also back to spinal cord levels S2,S3,S4
Name differential diagnoses of perineal pain
- vaginal tear
- anal canal fissure
- perineal genital ulcers (e.g. herpes)
How do pain fibres get from the testis to the CNS?
- due to its embryological descent, visceral afferents run alongside sympathetic fibres back to the spinal cord to levels T10-11
- however, due to its close relationship to the scrotal wall (body wall), pain from the testis can also present localised to the scrotum and or groin (L1 region)
Name differential diagnoses of scrotal pain
- skin lesions
- strangulated inguinal hernia
How do we control micturition (urine flow)?
- the nerve fibres entering and leaving the spinal cord levels S2-S4 are key in the control of micturition
- visceral afferent fibres
- pelvic splanchic nerves (carrying parasympathetic fibres that have left the CNS with S2,3,4)
- pudendal nerve; S2,3,4 but this nerve carries somatic sensory and motor nerve fibres
As the bladder fills, it is sensed by what?
Stretch receptors at the end of visceral afferent nerve fibres, this is relayed to the CNS via S2,S3,S4 spinal cord levels
What happens once t is appropriate to micturate?
- the cerebral inhibition of the reflex is lifted and there is a co-ordinated contraction / relaxation of various muscles;
- the detrusor muscle contracts (parasympathetic)
- the internal urethral sphincter (parasympathetic), external urethral sphincter and levator ani muscles relax (somatic motor)
- the anterolateral abdominal wall muscles contract to increase intra-abdominal pressure and force urine out of the external urethral orifice (somatic motor nerve fibres)
The pudendal nerve arises from where?
From the sacral plexus
