Anatomy Flashcards
What is the urinary tract?
all the structures urine passes through from production to excretion
What are the main parts of the urinary tract?
- kidneys make urine
- ureter drains urine
- bladder stores/voids urine
- urethra excretes urine
Where do user urinary tract infections spread?
to the kidneys
Where do lower urinary tract infections spread?
to the urethra and bladder
Where are the kidneys?
in the retroperitoneum
Where are the ureters and bladder?
proximal ureters- abdomen
distal ureters- pelvis
bladder- pelvis
Where is the urethra?
proximal- pelvis
distal- perineum
What surrounds the kidneys?
- posterior to their own visceral peritoneum
- enclosed within renal fat
- surrounded by skeletal muscles
What skeletal muscles are the kidneys surrounded by?
- posterior abdominal wall
- muscles of back
- antero-lateral abdominal wall (eg external and internal oblique and transverses abdominis)
What can protect the kidney from trauma?
muscle guarding
What is the exact kidney position?
- anterior to the quadrates lumbrum
- lateral to the psoas major
- lateral to the vertebral bodies
- posterior if the floating ribs
- kidneys are in the L/RUQ
What vertebral bodies do each of the kidneys sit lateral to?
- right= L1-3
- left= T12-L2
What direction do the kidneys move on breathing?
- inferiorly on inspiration
- superiorly on expiration
Where is the hepatorenal recess?
between the right kidney and the liver
What is the location of the renal veins compared to the renal arteries?
veins are anterior to the arteries
Where does the lymph from the renal system go?
- from the kidneys to the lumbar nodes
- from the ureters to the lumbar and iliac nodes
What is the ureteric arterial blood supply?
branches of the renal artery, AA, common iliac, internal iliac and vesical artery
What are the two possibilities for renal artery stenosis?
- combined with infra-renal AAA as both as caused by atherosclerosis
- due to suprarenal AAA as there is occlusion of the proximal renal artery by aneurysm
What are the main parts of the kidney?
- cortex
- medulla
- pyramid
- capsule
What is the passage of urine?
nephron’s collecting duct –> minor calyx –> major calyx –> renal pelvis –> ureter
Where does the passage of urine tube get wider or narrower from collecting duct to ureter?
gets wider until constriction at the pelviureteric junction
Where are the other contractions in the path of urine?
- where ureter crosses the anterior of the common iliac artery
- ureteric orifice (opens into one corner of the trigone on bladder floor)
What are renal stones?
renal calculi are formed from urine calcium salts and can obstruct the urinary tract from within
What are the main ways of ureteric obstruction?
- internal obstruction from calculus or clot
- external obstruction from compression eg tumour
What is the response to ureteric obstruction?
increased peristalsis proximally so colicky pain
there will be back pressure of the urine
What is renal failure?
failure to adequately filter the blood to produce urine
What is hydronephrosis?
painful stretching of renal capsule as urine back pressure compresses nephrons so there is renal failure
What is the ureter path?
- from retroperitoneum through false pelvis into the true pelvis
- through pelvic floor
- into perineum
What does the pelvic floor do?
(made of pelvic diaphragm called levator ani)
separates the pelvic cavity and perineum
Where do the ureters run?
- completely sub-peritoneal
- turn medially at the level of the ischial spine to enter the posterior bladder
- enter badder wall in an inferomedial direction
Why do the ureters enter the bladder in the way they do?
inferomedially to prevent reflux during bladder contraction
What is the most inferior part of the male peritoneal cavity?
rectovesicle pouch
What attaches the uterus to the perineum?
the round ligament via the inguinal canal
What is the most inferior part of the female peritoneal cavity?
rectouterine pouch of Douglas
What is the difference in the ureter path in males and females?
- males the ureter runs inferiorly to the vas deferens
- females the ureter runs inferiorly to the uterine tubes and uterine artery
What are the majority of arteries entering the pelvis?
branches from the internal iliac artery
What makes up the three points of the trigone?
the two superior are the ureteric orifices
the one inferior is the internal urethral orifice
What does the detrusor muscle do?
- bulk of the bladder wall
- encircles the ureteric orifices to prevent reflex of urine
- forms the internal urethral sphincter muscle which contracts during ejaculation to stop semen going into the bladder
Where does the bladder sit?
the most anteriorly (the uterus in females is above and behind it)
How does the fullness of the bladder change its location?
- empty bladder lies in the pelvis
- full bladder extends our of the pelvis above pubic bone
What covers the surface of the bladder?
the peritoneum only ever covers the superior surface
What is the length of the urethra?
female is 4cm
male is 20cm
What are the
prostatic
membranous
penile/spongy
Where do the testis develop?
next to the kidneys and descend through the inguinal canal to the scrotum
Where do the testis sit in the scrotum?
in a sac called the tunica vaginalis (like a fist in a balloon)
What is a hydrocele?
excess fluid in the tunica vaginalis of the testes
What is included in the spermatic cord?
- vas deferens= transports sperm
- testicular artery= supplies oxygenated blood to testis
- pampiniform plexus= drain gin deoxygenated blood from testis
What does twisting of the spermatic cord cause?
severe pain and danger of testicular necrosis
What is in the deep inguinal ring?
- testicular artery and vein (pampiniform plexus drains into this)
- vas deferens
- lymphatics
- nerves
What are the palpable structures in the testis?
- vas deferens begins at the inferior pole of the testis and can be palpated superiorly to the testis
- epididymus can be palpated posteriorly to the testis
What is the path of sperm?
- sperm develops in the seminiferous tubules of testes
- epididymus
- vas deferens
- through abdominal wall in inguinal canal to pelvic cavity
- connects with seminal gland to become ejauclatory duct
- R and L with prostate gland drain into urethra
- opens at external urethral meatus
Where is the prostate gland?
- inferior to bladder
- walnut sized gland around the prostatic urethra
- inferiorly is the levator ani
What part of the prostate is felt on palpation PR?
the peripheral zone which is where cancers arise usually
What is the root of the penis attached to?
the ischium of the pelvis
What are the parts of the penis inside?
- right and left corpus cavernous transmit the deep arteries of the pelvis
- corpus spongiosum transmits the spongy urethra and expands distally to from the glans
What happens to the three penile cylinders during erection?
they become engorged with blood at arterial pressure
What is the penis blood supply?
- deep arteries of the penis
- branches of the internal pudendal artery (from internal iliac)
What is the scrotal blood supply?
- internal pudendal
- external iliac branches
Where does lymph from the scrotum and the penis (not glans) go?
drains to superficial inguinal lymph nodes in groin superficial fascia
Where does the lymph from the testis go?
drains to the lumbar nodes around the abdominal aorta
What is the sensory supply to the body wall?
to CNS by somatic sensory nerve fibres
What is the sensory supply to the organs?
to CNS by visceral afferent nerve fibres
What is the motor supply to the body wall?
conveyed from CNS by somatic motor nerve fibres and stimulate skeletal muscles to contract
What is the motor supply to the organs?
from CNS by nerve fibres called sympathetics and parasympathetics
What is the general rule for sensory supply to the pelvis and perineum?
- pelvis is visceral afferent
- perineum is somatic sensory
What does ureteric peristalsis and bladder contraction?
sympathetic and parasympathetic
What does urethral spinster control?
- sympathetic and parasympathetic (internal sphincter)
- somatic motor (external sphincter and levator ani)
What does renal system sensory pain?
visceral afferent (but urethra in perineum is somatic sensory)
Where do sympathetic nerve fibres leave the CNS and how do they get to where they need to be?
between T1-L2
- reach body wall within spinal nerves
- reach smooth muscle/glands of body within splanchnic nerves
- reach head by hitching a ride on arteries
What do spinal nerves contain?
somatic motor and sensory fibres and sympathetic fibres for smooth muscle and glands of body wall
How do the sympathetic nerves get to the renal system?
- leave spinal cord at T10-L2
- enter and then leave the sympathetic chains via abdominopelvic splanchnic nerves
- synapse at abdominal sympathetic ganglia around the AA
- postsynaptic fibres run along arteries in periarterial plexuses along with parasympathetic and visceral afferent fibres
How do the parasympathetic fibres get to the renal system?
- leave CNS by 3,7,9+10 and sacral nerves
- reach the handout and pelvic organs via pelvic splanchnic nerves
- from kidney to ureters= CNX
- to bladder= S2-4
- they then use peri-arterial plexuses to move back
Where do the somatic fibres go to in the renal system?
the perineum so the urethra end, its sphincter and levator ani
Where does kidney pain get felt?
posterior flank on affected side as a dull/achy pain
Where does pain from calculus in ureter get felt?
radiated from loin to groin of affected side
Where does bladder pain get felt?
midline suprapubic which is a dull/achy pain
Where does perineal urethra pain get felt?
localised to the perineum and is a sharp pain
Where does testis pain get felt?
in scrotum and can radiate to groin and anterior lower abdomen
How do visceral afferents go back to the CNS from the kidneys?
with sympathetics back to T11-L1 (with a common differential of muscular pain)
How do visceral afferents go back to the CNS from the ureters?
to T11-L2
How do visceral afferents go back to the CNS from the bladder?
- touching the peritoneum: with sympathetics to T11-L2
- rest of the bladder: with parasympathetics back to S2-4
How do the visceral afferents from the proximal urethra get back to the CNS?
with the parasympathetics back to S2-4
How do the somatic sensory fibres from the distal urethra go back to the CNS?
within pudendal nerve to S2-4
How do visceral afferents from the testis get back to the CNS?
with sympathetics to T10-11 (pain can also present localised to the scrotum due to the close relationship with the scrotal/body wall)
What do S2-4 nerves carry?
visceral afferents, parasympathetics, somatic motor and somatic sensory so they control urine flow
What is the first part of the urination reflex (needing to pee part)?
- bladder fills and visceral afferents detect this
- relayed to the CNS by S2-4
- reflex to empty bladder by detrusor stimulation and internal sphincter inhibition (in males)
- brain overrides this reflex
What is the second part of the urination reflex (peeing part)?
- detrusor contracts (P)
- internal urethral sphincter (P), external urethral sphincter + levator ani (somatic motor) relax
- anterolateral abode wall muscles contract to increase intra-abdominal pressure and force urine out (somatic motor)
What nerves arise from the sacral plexus?
- pudendal from S2-4
- sciatic from L4-S3
How is ureteric peristalsis regulated?
auto-regulated by ureteric cells
How is bladder contraction done?
parasympathetic fibres S2-4
In males, what controls the internal urethral sphincter?
- sympathetic to contract during ejaculation
- parasympathetic to relax for urinating
How is the external urethral sphincter operated?
somatic motor with S2-4 for contraction
How is the levator ani operated?
somatic motor within nerve to levator ani (S3-4) for contraction
Why does the left kidney lie higher than the right?
the right is below the liver
What level is the hilum at?
- left is at L1
- right is at L1/L2
What is in the renal hilum?
- renal pelvis is posterior
- renal artery is middle
- renal vein is anterior
- lymphatics
- nerves
- renal sinus fat
Why is the left renal vein longer than the right?
it passes across the aorta anteriorly to join the right sided IVC
What are the strengths of US for imaging the kidney?
- renal size
- cortical scarring
- doppler
- distension of pelvicalyceal system
- calculi
- detection of renal abnormalities
- cheap
What are the weaknesses of US for imaging the kidneys?
- user dependent!
- limited characterisation of focal lesions
- no licensed contrast medium (micro-bubble contrast only licensed for hepatic US use)
What are the strengths of CT for imaging the kidney?
- quick
- multi-phasic assessment of kidney
- vascular assessment
- characterises most pathologies
- high spatial resolution
- multiplanar imaging possible
What are the weaknesses of CT for imaging the kidneys?
- high dose ionising radiation
- contrast induced nephropathy
What is seen on CT pre-contrast in the kidney?
calculi best
What is seen 25-70s after contrast has been injected on CT?
cortical enhancement (corticomedullary)
What is seen 80-180s after contrast has been injected on CT?
renal medulla and cortex equally (nephrographic)
What is seen 5-15m after contrast has been given on CT?
opacification of the renal collecting system and ureters
What is contrast induced nephropathy?
- impairment of renal function occurs within 3 days following contrast
- rise in serum creatinine and urea
What are the risk factors for contrast induced nephropathy?
- renal impairment - +/- diabetes mellitus
- dehydration
- congestive heart failure
- LV ejection fraction < 40%
- acute MI (within 24 hours)
nephrotoxic drugs
What are the strengths of MRI for kidney imaging?
- excellent tissue contrast resolution
- renal lesion characterisation
- vascular assessment
- characterises most pathologies
What are the weaknesses for MRI for kidney imaging?
- lengthy acquisition
- nephrogenic systemic fibrosis
Where are the three anatomical locations where the ureters narrow in diameter?
- pelviureteric junction (PUJ)
- ureter enters the pelvis and crosses over the common iliac artery bifurcation
- vesicoureteric junction (VUJ) as ureter enters bladder
Where does the ureter enter the pelvis?
at bifurcation of common iliac artery
What is the CT urogram used for?
assessing the collecting system, ureters and bladder
What is the commonest imaging for the bladder?
US with a full bladder
What is the best imaging for a tear in the bladder wall?
cystography to see leak
What can CT urogram for the bladder by used for?
- visualising the whole collecting system
- nodal and metastatic disease staging
What is the gold standard for local staging of bladder wall tumours?
MRI
What is urethrogram used for?
strictures, trauma and diverticula in the urethra
What is US used for in genital imaging?
- testes/scrotum
- uterus and ovaries
- prostate biopsies
What is hysterosalphinogram used for?
- infertility and tubal patency
- uterine abnormalities
What is MRI used for in genital imaging?
- prostate cancer local staging
- abnormalities not seen properly on US
What do the kidneys reabsorb?
- fluid
- salt
- glucose
- amino acids
- urea
What is in the glomerular filtrate?
blood without RBCs and large plasma proteins
What is reabsorbed into the blood in the PCT?
glucose, amino acids, salt, water, (phosphate, sulphate and lactate)
What is secreted in to the nephron in the PCT?
H+, hippurates, neurotransmitters, bile pigments, uric acid, drugs and toxins
What is the difference between transcellular and paracellular reabsorption?
- transcellular: reabsorption across the cell layer that makes up the wall of the nephron
- paracellular: varies upon how tight/leaky the nephron is
What does secondary active transport need?
uses sodium ion gradient to move substances
Where is Na+ reabsorbed into blood?
everywhere except the descending loop of Henle
How is salt reabsorbed in the PCT?
- Na+ comes into the cell with glucose or with amino acids or through a H+ exchange
- Na+ then goes out of cell by K+ exchange
- H20 and moves down osmotic cell in same direction as Na+
- Cl- is reabsorbed passively through the paracellular route due to electrochemical gradient
How is glucose absorbed in the PCT?
- cotransport of Na+ and glucose into cell
- facilitated diffusion of glucose out of cell
- K+Na+ pump makes the Na+ gradient by pumping it out
- water moves by osmosis
Where is all the glucose that is filtered from the blood reabsorbed?
PCT
What happens in the ascending limp of the loop of Henle?
- no H20 reabsorption
- Na+ and Cl- reabsorption
there is decreasing concentration as you go up the limb
What happens in the descending limp of the loop of Henle?
- no NaCl reabsorption
- highly permeable to H2O
there is increasing concentration as you go down the limb
Where is the highest and lowest osmolarity in the nephron?
high osmolarity in the medulla
low osmolarity in the cortex
What substance also contributes to the concentration gradient in the loop of Henle?
urea adds solute to the interstitial fluid
What is normal urine output?
1ml/min (can be 0.3-25ml/min depending on ADH)
What adaptation does the vasa recta have to maintain gradient?
countercurrent exchange system to maintain gradient but passive exchange so the solute is not washed away
What action does ADH have on the collecting duct?
increases water reabsorption
What action does aldosterone have on the collecting duct?
increases Na+ reabsorption and increases H+/K+ secretion
What actions do ANH and PTH have on the collecting duct?
ANH= decrease in Na+ reabsorption PTH= increase in Ca2+ reabsorption and decrease in PO42- reabsorption
What happens in the early DCT?
Na+K+2Cl- for NaCl reabsorption
What happens in the late DCT?
- Ca2+ reabsorption and H+ secretion
- Na+ and K+ reabsorption depending on aldosterone
What is the permeability of the late collecting duct?
low ion permeability and a permeability to water dependent on ADH
What detects dehydration?
hypothalamic osmoreceptors detect dehydration
ADH is made in hypothalamus and secreted from posterior pituitary
What does ADH do?
- vasopressin binds to receptor and ATP is made into cAMP
- aquaporins are inserted into the membrane
- more water is reabsorbed
What change does ADH bring about in the urine?
- high ADH= hypertonic urine, small volume of urine with high osmolality
- low ADH= hypotonic urine, large volume of urine with low osmolarity
What happens if the collecting duct goes into the medulla?
water is lost and fluid becomes concentrated (!if there is little ADH there are no aquaporins so cells of DCT and collecting duct are impermeable to water)
What happens to ADH when there is hypovolaemia or hypotension?
activation of left atrial volume receptors (stretch receptors) so increase in ADH
What extrinsic substances change ADH levels?
nicotine stimulates ADH
alcohol inhibits ADH
What and how does aldosterone have an action?
- secreted by adrenal cortex
- in response to high K or low Na or activation of renin
- slow acting
- causes Na reabsorption and K secretion
- INCREASE in BP
What does an increase in [K+] stimulate?
directly stimulates adrenal cortex so there is K+ secretion
What does a decrease in [Na+] stimulate?
indirectly stimulates secretion of aldosterone by juxtaglomerular apparatus
What causes renin to be released from granular cells?
- decreased BP in afferent arteriole
- macula dense cells sense decrease in NaCl
- increased sympathetic activity due to low arterial BP
How does aldosterone decrease sodium?
- increases the number of basolateral NaK pumps and increases their activity to reabsorb more sodium
- increases expression of apical Na so more Na into cells
Why is a low sodium diet and a loop diuretic given in HF?
- low CO and BP
- high aldosterone
- salt and water retention
What hormone is secreted when the atrium is stretched due to high BP?
ANP which causes excretion of Na+ so water leaves and there is decreased plasma volume
