10-02-23 - The urinary system Flashcards
Learning outcomes
- Describe the anatomy (position, topography, function, relations, neurovascular supply) of the kidney
- Describe the anatomy (position, topography, function, relations, neurovascular supply) of the ureter
- Discuss the clinical implications of the anatomy of the kidney and ureter
- Give a brief overview of the anatomy (position, topography, function, relations, neurovascular supply) of the bladder and urethra in preparation later learning
- Display an insight into the control of bladder function and micturition
What are 4 parts of the urinary system/tract?
What are they each responsible for?
- 4 parts of the urinary system/tract:
1) Kidney: produces urine
2) Ureter: drains urine (from the kidney to the bladder)
3) Bladder: stores/voids urine (voiding = “emptying”)
4) Urethra: excretion of urine
Case 2
What can levels of haematocrit, Haemoglobin and RBCs indicate?
What is urea a waste product of?
What is creatinine a waste product of?
What is potassium needed for?
- Levels of haematocrit, Haemoglobin and RBCs can indicate haematopoiesis
- Haematocrit is the ratio of the volume of red blood cells to the total volume of blood.
- Urea is a waste product of dietary protein
- Creatinine is a waste product of muscle metabolism
- Potassium is needed for regulation of electrolyte balance
What 8 factors in homeostasis does the kidney regulate?
- 8 factors in homeostasis does the kidney regulate:
1) Removal of end-products of protein metabolism and drug metabolism
2) Production of renin
* Blood pressure control (Renin-angiotensin-aldosterone system)
3) Regulation of fluid (water) balance
* Blood pressure control
4) Regulation of electrolyte (Na, K, etc) concentration
5) Re-absorption of glucose and amino acid
6) Stabilization of blood pH (acid-base balance)
7) Production of erythropoietin
8) Vitamin D metabolism (Ca and P homeostasis)
How is the kidney referred to in Latin and Greek?
Where can the kidneys be found?
Is the kidney intraperitoneal or retroperitoneal?
How are kidneys kept in place?
- Kidney in Latin – Ren
- Kidney in Greek – nephros
- Kidneys are found on the posterior abdominal wall, below the diaphragm
- The kidneys are primary retroperitoneal
- Kidneys are kept in place e by the renal vessels and renal fascia
Why do we need to know the surface projections of the kidneys?
At what level are the kidneys located between?
What structure are the kidneys deep to?
Why is the right kidney 1cm inferior to the left kidney?
How much do the kidneys descend in inspiration?
What 4 structures do the kidneys sit on?
- We need to know the surface projections of the kidney for percutaneous kidney biopsies, where needles get inserted into the kidney
- The kidneys are located between upper borders of T12 and L3 vertebrae
- The kidneys are deep to the last 2 ribs
- Right kidney is 1 cm inferior to the left liver due to liver
- The kidneys may descend 1-2 cm with deep inspiration
- 3 structures the kidneys sit on:
1) Quadratus lumborum
2) posterior abdominal wall muscles
3) Psoas major slightly (medially)
4) Transverse processes of vertebrae
Label this CT image with contract agent looking from the feet upwards
What are the 4 layers of the encapsulation of the kidney?
What fills the renal sinus?
How is the kidney kept in place?
- 4 layers of the encapsulation of the kidney (from inside out):
1) Fibrous capsule
2) Perirenal (perinephric) fat
* Fills renal sinus as well as the renal pelvis (mostly renal pelvis)
3) Renal fascia
* Covers suprarenal gland as well
* Keeps kidney in place
4) Pararenal fat
Describe the 5 main parts of the kidney from outside to inside?
- 5 main parts of the kidney from outside to inside:
1) Renal cortex
2) Renal medulla
* Has 8-10 renal pyramids
* Contains the renal papilla located at the apex of the renal pyramid
* The renal papilla projects into the minor calyx
3) Renal columns of Bertin
* Extensions of the cortex around pyramids
4) Renal sinus (medial)
* Mostly filled with renal pelvis, with the rest being filled with perineal fat
5) Hilum
* In the hilum, the most anterior structure is the renal vein, then segmental renal arteries, then the renal pelvis (VAAAPA from anterior to posterior)
Describe the 5 main parts of the kidney from outside to inside?
- 5 main parts of the kidney from outside to inside:
1) Renal cortex
2) Renal medulla
* Has 8-10 renal pyramids
* Contains the renal papilla located at the apex of the renal pyramid
* The renal papilla projects into the minor calyx
3) Renal columns of Bertin
* Extensions of the cortex around pyramids
4) Renal sinus (medial)
* Mostly filled with renal pelvis, with the rest being filled with perineal fat
5) Hilum
* In the hilum, the most anterior structure is the renal vein, then segmental renal arteries, then the renal pelvis (VAAAPA from anterior to posterior)
What is located in the outer renal cortex and inner renal medulla?
How do the nephrons in the renal cortex and renal medulla differ?
- The outer renal cortex is where 80% of nephrons are located
- In the renal medulla, there are collecting tubules and the remaining 20% of nephrons
- Nephrons in the renal medulla filters blood and concentrates urine, which can be used as a diagnostic tool
What are nephrons?
What are 3 roles of nephrons?
What are the 4 parts of the kidney nephrons?
Where do nephrons drain their filtrate?
What structures are around the convoluted tubes loop of Henle?
- Nephrons are the functional unit of the kidney
- 3 roles of nephrons:
1) Ultra-filtration (ultra-filtrates blood)
2) Excretion
3) Re-absorption - 4 parts of the kidney nephrons:
1) Renal corpuscle
* Glomerulus
* Bowman’s capsule
2) Proximal convoluted tubule
3) Loop of Henlé
4) Distal convoluted tubule
- Nephrons drain the filtrate to collecting ducts
- Around the convoluted tubes and loop of Henle, there is a rich artery venous system, where reabsorption and sometimes excretion takes place
Where does filtrate from the collecting ducts empty through?
What do minor calyces empty into?
Where do the major calyces empty into?
What does the renal pelvis fill?
What does it continue on as?
- The filtrate coming from the collecting ducts empty through the renal papillae into minor calyces, so it is now urine
- Minor calyces empty, in turn, into two or three major calyces
- The major calyces enter into the renal pelvis, which is the upper dilated portion of the ureter
- The renal pelvis fills most of the renal sinus and continues as the ureter
What are the functions of the renal arteries?
Where do renal arteries arise from?
Where do they rely in relation to the renal veins?
Where do they divide?
Where do renal veins drain into?
Where does the left renal vein pass under?
Why can this be problematic?
What structures do the left and right testicular veins open into?
- The renal arteries are both functional and nutritional (unlike the lungs)
- The renal arteries arise from the aorta between L1/2
- The renal arteries lie posterior to the renal veins
- The divide into branches at the hilum of the kidneys
- Renal veins drain into the IVC
- The left renal vein passes under the superior mesenteric artery
- The left renal vein can become compressed by the superior mesenteric artery, leading to varicocele
- This means varicocele (mass of varicose veins in the spermatic cord) is more common on the left side
- The left testicular vein opens into the left renal vein, whereas the right testicular vein opens into the IVC directly
- This is known as the left renal vein being in the ‘nutcracker’
What are the 6 divisions s of the renal arteries?
- 6 divisions s of the renal arteries:
1) 4-6 segmental arteries divide into
2) Lobar arteries divide into:
* 1 lobar artery for each renal pyramid
3) Interlobar arteries divide into:
* Before entering the renal substance, each lobar artery gives off 2 or 3 interlobar arteries
4) Arcuate arteries divide into:
* At the junction of the cortex & medulla the interlobar arteries give off the arcuate arteries that arch over the bases of the pyramids
5) Interlobular arteries divide into:
* The arcuate arteries give off several interlobular arteries that ascend in the cortex
6) Afferent arterioles
* These branches go into bowman’s capsule to from the glomerulus, which is where filtration takes place
* The afferent glomerular arterioles (that give blood directly into the renal corpuscle) arise as branches of the interlobular arteries
Kidney relations diagram
What is the ureter?
Where does the ureter start?
Is the ureter intraperitoneal or retroperitoneal?
What 2 structures is the ureter anterior to?
How long and wide is it?
What structure does the ureter have a close relationship to?
Where does the ureter cross the common iliac artery?
- The ureter is a Muscular tube that transports urine from kidney to bladder
- The ureter starts at the hilum
- The ureter is retroperitoneal and on the posterior abdominal wall
- 2 structures the ureter is anterior to:
1) Psoas major and
2) Branches of the lumbar plexus - The ureter is 25-30 cm long and 1-10 mm wide
- The ureter has a close relationship to the gonadal vessels (testicular/ovarian vessels)
- It crosses the common iliac artery or its bifurcation into the internal and external iliac
What 3 structures does the ureter cross in the pelvis in females?
What border does the ureter form?
What artery is the ureter crossed by in females?
- 3 structures the ureter crosses in the pelvis in females:
1) Umbilical artery
2) Obturator vessels
3) Obturator nerve - The ureter forms the posterior border of ovarian fossa in females (anterior border formed by internal iliac)
- The ureter is crossed by uterine artery near cervix
What 4 structures does the ureter cross in the pelvis in males?
- 4 structures the ureter crosses in the pelvis in males:
1) Umbilical artery
2) Obturator vessels
3) Obturator nerve
4) Ductus deferens (transport tube for sperm)
Is the umbilical artery open in adults?
What artery does it form?
What structure does the remnant form?
- The umbilical artery is open in adults
- It gives off the superior vesical artery to the upper part of the bladder then obliterates
- It is left as a remnant going towards umbilicus and becomes the medial umbilical fold/ligament
How does the ureter pass through the bladder wall?
What does it form?
What forces the flap valve to close?
What does this mechanism prevent?
- The ureters pass through the bladder wall obliquely, creating a flap valve
- Pressure of urine in the full bladder force the “valve” to close
- This mechanism prevents urine returning into the ureter (ureteric reflux) as this can lead to kidney failure
Ureter: reformatted CT
What is an Intravenous Pyelogram (IV Urogram).
Example in picture
- An Intravenous Pyelogram (IV Urogram) is another diagnostic method that uses contract which is filtered through the kidneys
- Example in picture
Case 2
Ureterolithuasis (ureter stones):
* Complaints (3)
* Physical exam (3)
* Urinalysis (3)
What are the 3 ureter constrictions?
Where are ureter stones likely to get stuck?
What are stones that block the renal pelvis called?
What kind of pain do stones in the ureter cause?
How does the ureter pass stones?
- 3 ureter constrictions:
1) Uretero-pelvic junction (UPJ)
2) Ureter crossing the iliac vessels at the pelvic inlet
3) Ureteric orifice as it passes through the bladder wall - Ureter stones (Ureterolithiasis) are likely to block one of these constrictions
- Sometimes, stones can be so large they block the renal pelvis – these are called a staghorn calculus
- Stones in the ureter cause severe intermittent pain until they pass into the bladder
- The ureter is a smooth muscle, so uses peristaltic waves to push the stone to the bladder
What are 4 different arterial branches that supply the ureter along its length?
- 4 different arterial branches that supply the ureter along its length:
1) Renal arteries
2) Gonadal arteries
3) Aorta
4) Common iliac arteries
Where do the nerves of the kidney arise from?
Where do sympathetics to the kidney come from?
What 3 structures are the nerves to the abdominal part of the ureters derived from?
Where do visceral afferents of the kidney/ureters return to?
What 4 places is pain from the kidneyureters referred to?
What causes the nausea and vomiting associated with kidney/ureter?
- The nerves to the kidneys arise from the renal nerve plexus from the coeliac and aorticorenal ganglia
- Sympathetics to the kidney come from the abdominopelvic (especially the least) splanchnic nerves
- 3 structures the nerves to the abdominal part of the ureters are derived from:
1) Renal plexus
2) Abdominal aortic plexus
3) Superior hypogastric plexus - Visceral afferent fibers of the kidney/ureters return to T11 to L2 spinal cord levels
- 4 places pain from the kidney/ureters is referred to:
1) Loin
2) Groin
3) Scrotum
4) Labia - Afferents in the vagus nerve (CN X) may cause the nausea & vomiting associated with kidney and ureter pain
Where does the lymph drainage of the kidneys go to?
What 3 places do lymphatics of the ureters drain to?
- Lymph drainage of the kidneys to lateral aortic (lumbar) lymph nodes
- 3 places lymphatics of the ureters drain to:
1) Lateral aortic (lumbar) lymph nodes
2) Common iliac lymph nodes
3) Internal iliac lymph nodes
Is the bladder intraperitoneal or retroperitoneal?
What does it act as?
How much urine can it store?
When is it located when empty in adults?
Where does it rise to when full?
What are the 4 different surfaces of the bladder?
Where does the median umbilical fold extend between?
- The bladder is a retroperitoneal muscular sac
- The bladder acts as a Temporary urine reservoir
- It can store 300-600 mL (max ~1 L), with its shape and position varying depending on how full it is
- The bladder is posterior to the pubis when empty (in adults)
- The bladder rises 5-7cm above pubic symphysis when full
- 4 different surfaces of the bladder:
1) Apex
* Connected to umbilicus
* The median umbilical fold (Remnant of Urachus) extends between the apex and umbilicus
2) Fundus/Base/posterior surface
3) Infero-lateral surface
4) Neck
* Part of the bladder around the urethra
What are the deepest parts of the abdomino-pelvic cavity/greater sac in men and women?
What do they each separate?
How are each of these structures formed?
What does the rectouterine pouch separate in females?
Where will fluid in the peritoneal cavity accumulate when the patient is upright?
- Rectovesical (men) and rectouterine (women) pouches are the deepest parts of the abdominopelvic cavity/ greater sac
- The Rectovesical pouch in males separates the rectum from the urinary bladder
- The rectovesical pouch is formed by parietal peritoneum covering the posterior abdominal wall, then the superior 1/3rd of the rectum, then reflecting on itself and covering the superior wall of the bladder
- The Rectouterine pouch (of Douglas) in females separates the rectum from the uterus
- The rectouterine pouch if formed by parietal peritoneum covering the posterior abdominal wall, then the superior 1/3rd of the rectum, then reflecting on itself and covering the uterus
- The vesicouterine pouch in females separates the urinary bladder from the uterus
- When a patient is upright, fluid in the peritoneal cavity will accumulate in the rectovesical pouch in men and the rectouterine pouch in females
Where does the bladder rest in males and females?
How is the neck of the bladder held in place in males?
In males, what structures is between the base of the bladder and the rectum?
What are these structures related to inferiorly?
- In males and females, the bladder rests on the pelvic floor
- In males, the neck of the bladder is held in place by the puboprostatic ligament
- In males between the base/fundus of the bladder and the rectum, there are several glands and the ampulla of the vas deference
- These structures are inferiorly related to the prostate gland
How is the neck of the bladder held in place in females?
In females, what structures sit on top of the bladder?
What structures is the posterior part of the bladder and urethra related to?
What can occur to these structures after pregnancy?
- In females, the bladder is held n position by the pubovesical ligament
- In females, the cervix and the rest of the uterus lie on the superior surface of the bladder
- The posterior part of the bladder and the urethra is related to the vagina in women
- After pregnancy, these structures can be disrupted, which can result in the bladder prolapsing into the vagina
What is the detrusor muscle?
How is it controlled?
What does the middle layer of the detrusor muscle form in males?
Is the urethral sphincter voluntary or involuntary?
What controls the urethral sphincter?
What is the function of the urethral sphincter?
When is the urethral sphincter open and closed?
- The detrusor muscle is the 3 layered smooth muscle (+mucosa) of the bladder
- The detrusor muscle is mainly under parasympathetic influence
- Toward the neck of the male bladder, middle layer of detrusor muscle condenses and forms the internal urethral sphincter
- The urethral sphincter is involuntary (as it is a smooth muscle) and is under parasympathetic control
- The urethral sphincter is always closed by the sympathetics, and parasympathetics opens it
- The parasympathetics cause the contraction of the detrusor muscle, so urine will flow out of the bladder into the urethra
When can the folds of the mucosa of the bladder be seen?
What is the role of these folds?
What is the epithelial lining of the mucosal folds?
What is the trigone of the bladder?
What 2 structures can be found at the trigone of the bladder?
- Folds of the mucosa can be seen when the urinary bladder is empty
- These folds allow the bladder to expand (distend) when it is filled with urine
- The epithelial lining of the mucosal folds is transitional epithelium or urothelium that is urine-proof & allows distension
- The trigone of the bladder is the triangular area on the mucosa.
- 2 structures that can be found at the trigone of the bladder:
1) Openings of the ureters (at the corners)
2) Urethral opening (at the apex)
What are 4 parts of the male urethra?
What structures can be located at each one?
- 4 parts of the male urethra:
1) Pre-prostatic (intramural) urethra
* Surrounded by involuntary internal urethral sphincter
2) Prostatic urethra (within prostate gland)
3) Membranous urethra (in pelvic wall)
* Surrounded by voluntary external urethral sphincter
4) Spongy (penile) urethra
* Openings of the ducts of mucus-secreting urethral glands (glands of Littré)
How long and wide is the female urethra?
What structure is located at the distal urethra?
What structure is present in the male urethra, but absent in the female urethra?
What structure is the female urethra related to?
Where does it open?
How can the layout of the bladder in female contribute to urinary incontinence?
- The female urethra is 4cm long & 6mm wide
- There is the external urethral sphincter of striated muscle (voluntary) at distal urethra
- The female urethra doesn’t have an internal urethral sphincter as seen in males
- The female urethra is related to the anterior vaginal wall
- It opens between vagina and the clitoris
- In the female, the bladder neck is above the pelvic floor so that the pressure of pelvic organs as well as the levator ani contribute to urinary continence
Where do the ducts of the para-urethral glands (Skene’s glands) open?
- The ducts of the para-urethral glands (Skene’s glands) open on each side of the lateral margins of the urethra.
What are 5 branches of the internal iliac artery that supply the bladder and urethra?
What does the umbilial artery give off?
What is the venous drainage of the bladder and urethra?
What is the lymphatic drainage of the bladder and urethra?
Why is venous drainage of the bladder and urethra in males important?
- 5 branches of the internal iliac artery that supply the bladder and urethra:
1) Inferior vesical artery
2) Superior vesical
3) Middle rectal
4) Vagina
5) Internal pudendal - Umbilical artery gives off superior vesical artery before obliterating
- Venous drainage of the bladder and urethra - vesical and prostatic plexuses converging on internal iliac veins and internal pudendal vein
- lymphatic drainage of the bladder and urethra - internal & external iliac nodes
- Why Venous drainage of the bladder and urethra in males is important:
- From the prostate there are valveless venous communications (Batson venous plexus) with the internal vertebral venous plexus that may facilitate tumour spread
Where does nerve supply for the bladder and urethra come from?
Where do parasympathetics come from?
What are 2 effects of parasympathetics on the bladder and urethra?
Where do sympathetics come from?
What is an effect of sympathetics on the blader and urethra?
Where do somatic motor nerves come from?
What is an effect of somatic motor nerves on the bladder and urethra?
- Nerve supply for the bladder and urethra comes from the inferior hypogastric (pelvic) plexus
- Parasympathetics come from S2-4 via pelvic splanchnic nerves
- 2 effects of paraysmpathetics on the bladder and urethra:
1) Contract detrusor muscle
2) Relax internal urethral sphincter in males (allows for urination) - Sympathetics come from T10-L2
- Sympathetics contract internal urethral sphincter in males so the urethra will close during ejaculation
- Somatic motor (voluntary nerves from pudendal nerve (S2-4) & its branches
- Somatic motor nerves control the external urethral sphincter, when it is inhibited, we can urinate
Label this Male bladder MRI
What 2 ways can bladder catheters be placed?
How does repeated childbirth affect urinary incontinence?
- 2 ways can bladder catheters be placed:
1) Urethrally (most common approach in adults)
2) Suprapubically - Repeated childbirth may weaken the pelvic floor/diaphragm allowing the bladder to drop & hence affecting urinary continence
