Urinary System Flashcards
What layer does the kidney arise from?
Mesoderm
How many stages of kidney development are there?
3
What are the 3 stages of kidney development?
- Pronephros
- Mesonephros
- Metanephros
When does the pronephros development take place?
4th embryological week
Is the pronephros a functioning unit?
No
When does the meonephros develop?
Late in the 4th embryologic week
Which stage of development function as the interim kidney?
Mesonephros
What does the mesonehros develop into?
Mesonephric duct
Explain the development of the mesonephric duct in male development
Epididymis, vas deferns, ED
Explain the development of the mesonephric duct in female development
Mullarian duct > ureter, vagina
What stage of kidney development becomes the permanent kidney?
metanephros
When does the metanephros form?
End of the 5th week embryological development
When does the metanephros begin to function?
8 weeks gestation
What does the ureteric bud form? (4)
Ureters
Renal pelvis
Calyces
Collecting ducts
Where does the ureteric bud form from?
Mesonephric duct
What is the functional unit of the kidney?
Nephrons
Where do the nephrons arise from?
Intermediate mesoderm
During fetal growth where do the kidneys migrate to?
Migrate from the pelvis to the abdomen
At what week do the kidneys migrate during fetal development?
12-15 weeks gestation
What causes the kidney to migrate?
Result of rapid caudal growth (so they don’t really migrate)
When are where do the ureters develop?
Mesonephric duct (wolffian duct) at 4 weeks gestation
Where does the urinary bladder develop from?
Urogenital sinus
Is the urinary bladder continuous with the allantois?
Yes
Where does the allantois form?
Yolk sac
What does the allantois become?
Urachus
What is the urachus?
Median umbilical ligament
What is the purpose of the medial umbilical ligament?
Pathway the bladder takes from the abdomen to the pelvis
When does the bladder become a true pelvic structure in infants and children?
After puberty
In what retroperitoneal space does the kidneys and ureters lie in?
Perirenal space
In what gutter do the kidneys obliquely lie?
Paravertebral gutters
What muscle runs parallel to the kidneys?
Psoas muscle
The upper poles are located more what to the inferior poles?
Medial and posterior
Where do the IVC and aorta lie in relation to the kidneys?
Anterior
Where do the ureters enter the bladder?
Posterolateral aspect of the bladder
What is the relation of the ureters to the iliac vessels?
Anterior
How long are the ureters?
30cm
What is the diameter of the ureters?
2-8cm
What vertebral level does the upper and lower poles the kidneys sit?
T12 and L3
At what vertebral level is the hilum?
L1
What cavity does the bladder lie in?
Retroperitoneal
Where does the bladder sit in an empty state?
True pelvis
Where does the bladder sit in a distended state?
False pelvis/abdominal cavity
Where is the bladder in relation to the prostate?
Superior
What shape is the kidney?
Bean-shaped AKA reniform shaped
How are the medial and lateral aspects of the kidneys shaped?
Medial- concave
Lateral- convex
What are the dimensions of the adult kidney?
Length- 9-12cm
Width- 4-5cm
AP- 3cm
Which kidney is usually longer?
Left
The lengths of the adult kidney should be within how many cm of each other?
1.5-2cm
What is the size of a child’s kidneys?
Size will vary with age- charts generally available within department
What are the 4 layers if tissue that protects the kidneys?
- Thin fibrous capsule
- Perirenal fat
- Renal fascia
- Pararenal fat
Describe how the thin fibrous capsule that surrounds the kidney appears on US
Specular reflector that appears bright on US (echogenic)
What is the perirenal fat continuous with?
Renal sinus
What is another name for the renal fascia?
Gerota’s fascia
What is the purpose of the renal fascia?
Anchors the kidney to the posterior abdominal wall
What spaces does the renal fascia separate?
Separates the perirenal space from the pararenal space
What is ptosis?
A kidney that falls when fascia tears
What are the 2 distinct areas of the kidney?
Parenchyma and Sinus
What area of the kidney is the functional layer?
Parenchyma
What is the parenchyma divided into?
Cortex and Medulla
What portion of the kidney is the renal capsule?
Outer portion
Where is the site of urine production?
Renal cortex
What area of the kidney contains the functional units?
Cortex
What is the parenchyma that arches over the renal pyramids and extends between pyramids known as?
Columns of Bertin
What artery and vein does each column of Bertin contain?
Interlobular artery and vein
What is the medulla?
Inner portion of the parenchyma
What does the medulla consist of?
Pyramids
How many triangular structured pyramids are there?
8-18
What does the base of the pyramid point to?
Pointed toward the cortex
What does the apex of the pyramid point to?
Renal sinus (minor calyces)
When is a pyramid considered enlarged?
If they are thicker then the cortex
What is the fatty central portion of the kidney?
Renal sinus
What structures does the renal sinus contain?
Minor and major calyces, renal pelvis, vessels and nerves
How many minor calyces are there?
8-18
Does the minor or major calyce receive urine from the pyramids?
Minor calyce
How many major calyces are there?
2-3
What is another name for the major calyces?
Infundibula
What portion of the kidney does the major calyces join to?
Renal pelvis
What is the order from anterior to posterior are the vessels positioned in the renal hilum?
Renal vein
Renal artery
Ureter
Third branch of the renal artery
Which ureter is shorter? Right or Left?
Right
How does the ureter transport urine?
Peristalsis and gravity
What are the 3 natural points of narrowing?
- Ureteropelvic junction
- Pelvic brim (anterior to iliac vessels)
- Ureterovesical junction
What does bladder size and shape depend on?
Urine volume
What lines the inner walls of the bladder?
Inner muscos membrane containing rugae
What happens to the rugae of the bladder in an extended state?
Outline becomes smoother and distends with urine
What happens to the rugae when the bladder is in an empty state?
Membrane is wrinkled
What is the bladder capacity?
300-500ml
What is the volume measurement of the bladder?
AP X L X W X 0.52
Is a post void of < 100ml significant?
No
Does the trigone of the bladder change shape?
No, remains constant
What is the trigone?
Triangular area b/w the openings of the ureters and the urethra
Where is the trigone located?
Base/posterior surface of the bladder
What is the bladder neck?
Urethral opening
Does the bladder neck remain a content size ad shape?
Yes
Where is the apex of the bladder located?
Anterior and superior surface of the bladder
What attaches to the apex of the bladder?
Median umbilical ligament
What are the 4 layers of the bladder?
- Mucosa- inner layer containing rugae
- Sub-mucosa- connective tissue
- Muscle
- Serosa- peritoneum covering superior surface
What is the muscle layer of bladder?
Detrusor muscle
How many muscle layers of the bladder is there?
3
What does the muscle layer of the bladder form?
Sphincter muscle
What is the measurements for the distended state of the bladder wall?
3mm
What is the measurements for the non-distended state of the bladder wall?
6mm
What does the female urethra pierce to exist the bladder?
Urogenital diaphragm
What are the 3 areas of the male urethra?
- Prostatic
- Membranous
- Penile
What structures are anterior to the right kidney? (5)
- Right adrenal
- Right lobe of the liver
- 2nd part of to duodenum
- Right colic flexure
- Morrisons pouch
What structures are posterior to the right kidney? (4)
- Diaphragm (superiorly)
- Psoas muscle (posteriomedial)
- Quadratus lumborum muscle
- Costodiaphragmatic recess
What structures are anterior to the left kidney? (6)
- Left adrenal gland
- Body and tail of pancreas
- Spleen
- Stomach
- Jejunum
- Left colic flexure
What structures are posterior to the left kidney? (4)
- Diaphragm
- Psoas muscle (posteriomedial)
- Quadratus lumborum muscle
- Costodiaphragmatic recess
What structures is the right ureter posterior to?
Duodenum and terminal ilium
What structures is the left ureter posterior to?
Colon and left gonadal vessels
In males the pelvic portion of the ureter pass what to the ductus deferens?
Posteriorly
What is anatomical order of structures from anterior to posterior in the female pelvis, relating to the ureter?
Ovary > ureter > internal iliac artery > vein
What is anterior to the male and female bladders?
Space of Retizus
What structures are posterior to the male bladder? (3)
Rectum, vas deferens, seminal vesicles
What muscles are lateral to the male and female bladder?
Iliopsoas and obturator internus muscles
What is the relationship of the bladder to the prostate?
Posterioinferior
Are the levator ani muscles inferior to the male bladder?
Yes
What structures are posterior to the female bladder? (3)
Uterus, vagina, anterior-cul-de-sac
How is the adnexa positioned in relation to the bladder?
Posteroinferior
What is the total cardiac output to the kidneys?
1/4 of the cardiac output
Approximately how much blood passes through the kidneys (blood volume) per minute?
1200ml/min
What do the renal arteries branch into?
Interlobar arteries
What do the lobular arteries branch into?
Arcuate arteries
Where are the arcuate arteries located?
At the base of the pyramids
What do the arcuate arteries branch into?
Interlobular arteries
What arteries travel into the renal cortex?
Interlobular arteries
What do interlobular arteries branch into?
Afferent arterioles
Where do the afferent arteries travel?
Into the glomerulus of the nephron
How is the lymph fluid drained?
Para-aortic nodes
What is the ultrasonic appearance of a sagittal adult kidney?
Smooth, contoured, elliptical shape
What is the ultrasonic appearance of a transverse adult kidney?
Rounded and boken medially by the hilum
How does the capsule present on US?
Echogenic line bordering cortex
Describe the US appearance of the cortex
Extends from the sinus to the outer surface
Homogenous
Even thickness
Echogenicity equal to or slightly less echogenic than the liver
At what level do you assess and compare the kidney to the liver?
Assess and compare at the same level
Describe the US appearance of the medulla
Triangular rounded or blunted hypoechoic (anechoic) areas
Equidistant
What is the corticomedullary junction (CM junction)?
A marker used for measuring the cortical thickness
How does the corticomedullary junction appear as on US?
Pulsation and bright reflection of arcuate arteries
Describe the US appearance of the renal sinus?
Homogenous highly echogenic central area
What does the renal sinus appear as in a non hydride state?
Renal pelvis and infundibulum not well seen (collapsed)
What does the renal sinus appear as when over hydrated?
Small echo lucent areas within the sinus
What do the renal arteries appear as in US?
Linear anechoic tubes
What plane are the renal vessels best assessed in?
Transverse (long axis)
What structure can be mistaken for the renal arteries?
Crura
What is the US appearance of the cortex in infants and children?
Isoechoic or MORE ECHOGENIC compared to the liver
Thin compared to pyramids
Lobular contour (should disappear by age 6)
What is the US appearance of the pyramids in infants and children?
Hypoechoic and large
Ratio of the cortex to the medulla 1.64:1 (adult 2.59:1)
What is the US appearance of the sinus in infants and children?
Indistinct, hypoechoic due to very little fat
How is the paediatric kidney position different then an adult within the body?
Positioned lower in the abdomen
By what age do infants demonstrate an adult echo pattern?
6 months
When are ureters best visualized?
When dilated
What will the ureters appear like when dilated?
Anechoic tubular structure in sagittal
When is the distal ureter be assessed?
When there is a full bladder
Describe the ureteral jets
1-3sec stream of urine entering bladder from ureter
What does flow from the ureteral jets indicate?
Flow of urine not obstructed
How does the bladder appear on US?
cystic and anechoic
How does the bladder appear on US in a transverse plane with superior angulation?
Rounded
How does the bladder appear on US in a transverse plane with inferior angulation?
Squared
What are we checking for when scanning the bladder?
Wall irregularities/ shape
What transducer frequency would you use when scanning the kidneys?
3-5 MHz
What are the potential patient positions when scanning the kidneys?
Supine, decubitus or oblique
What planes are the kidneys assessed in?
Sagittal, coronal or transverse
What structure is used to help assess the right kidney?
Liver
What structure is used to assess the left kidney?
Spleen
What are some things you could do to optimize the image?
Breathing technique
Change pt position
Change windows
How are the ureters best visualized?
In long axis
How is the proximal ureter best visualized?
Coronal oblique plane using kidney as a window
How is the mid ureter best visualized?
Using grated compression to move bowel gas out of the way
What are the scanning techniques used for the bladder? (3)
- 3-5MHz transducer
- Sagittal and transverse planes
- Full bladder required
What are you supposed to check for when the dilated ureters or hydronephrosis?
Check for “jets”
What are you supposed to look for when there is a lesion noted in the bladder?
Check the kidneys for hydronephrosis
Are you supposed to do a post void image when a mass or fluid is collected within the space of Retzius?
Yes
What is the modality of choice to evaluate the bladder?
Cystoscopy
What do the kidneys regulate? (3)
- Osmotic pressure and volume of extracellular fluids by regulating the amount of sodium and water excreted
- Total concentration of water and electrolytes
- pH
What product is excreted by the kidneys?
Metabolic waste
What enzyme is secreted by the kidney?
Renin
What does renin affect?
Blood pressure
Can a person function with only 1 kidney? How?
Yes, because they function independently
How much urine is excreted daily?
1.2-1.5L - variable
What are the metabolic wastes excreted by the kidneys?
CO2, urea, uric acid, creatinine
How much fluid do the kidneys produce daily?
180L
What % of the processed fluid is retained from the kidneys and how much is excreted?
99% filtered and recirculated
1% excreted
What does the nephron do? (2)
Filter blood and produce urine
What are the 2 types of nephrons?
- Cortical (superficial)
2. Juxtamedullary (deep)
What are the 2 main components of the nephrons?
- Renal corpuscle
2. Renal tubule
What makes up the renal corpuscle? (2)
- Network of porous capillaries (glomerulus)
2. Membrane with filtration slits (Bowman’s capsule)
What makes up the renal tubule? (4)
- Proximal convoluted tube
- Distal convoluted tube
- Loop of henle
- Collecting duct
What is the function of the nephrons?
- Control blood concentrations and volume
- Helps regulate blood pH
- Removes toxins from blood
How are toxins removed from the blood?
Through osmosis and active transport
What path does the blood take to reach the nephrons?
Renal artery > interlobar artery > arcuate artery > interlobular arteries > interlobular artery > afferent artery > glomerulus
What are the 3 stages of urine formation?
- Glomerular formation
- Tubular reabsorption
- Tubular secretion
Describe the process of glomerular formation
- Afferent artery brought blood to the glomerulus
- An increase in BP forces water and dissolved substances through a membrane
- The combo of water and dissolved substances filters into bowman’s capsule producing filtrate
- Filtrate enters renal tubule
What does not pass through the membranes of the bowman’s capsule?
RBC
How do RBCs leave the glomerulus?
Efferent arteriole
Describe the process of tubular reabsorption
Nutrients in the filtrate are reabsorbed back into the bloodstream
What are the substances reabsorbed back into the bloodstream?
Water, glucose, vitamins and nutrients
What causes reabsorption to occur?
Peritubular capillaries at the PCT, ascending and descending loop of henle
Describe the process of tubular secretion
- Waste is secreted into the DCT
- Rids the body of certain substances and controls the blood pH
What is the bloods normal pH?
7.35 to 7.45
Where is the juxtaglomerular apparatus located?
The point where the DCT, afferent and efferent arterioles come into contact
What cells release renin?
Granular cells (afferent arterioles)
What cells inhibit renin release?
Macular cells (DCT)
What is the main function of the juxtaglomerular apparatus?
Regulate BP
What are the influencing factors that act on the kidney to help regulate BP? (3)
- ADH (antidiuretic hormone)
- Aldosterone
- Renin
What secretes ADH?
Posterior Pituitary
What is the function of ADH?
Aids in retaining water in the body
What stimulates the production of ADH?
Decrease in blood volume
What structure secretes Aldosterone?
Adrenal cortex
What does aldosterone act on?
PCT
What does aldosterone control?
Sodium reabsorption
What stimulates the production of aldosterone?
Increased blood volume
What system is aldosterone influenced by?
Renin-angiotension system
What secretes renin?
juxtaglomerular apparatus
What influencing factor in the kidney acts as a catalyst?
Renin
What does renin stimulate the formation of ?
Angiotensin
Angiotensin stimulates the release of what?
Aldosterone
Does renin respond to the stimulation of decreased or increases BP?
Decreased
How much loss of function can there be in the kidney before blood tests are elevated?
60%
What are the 3 blood tests that assessed for kidney function?
- Serum creatinine
- Blood urea nitrogen (BUN)
- Serum electrolytes
What is serum creatinine?
End product of muscle creatine phosphate metabolism that is filtered out of the kidneys
Easily excreted by kidneys and directly related to glomerular filtration rate
How much serum creatinine is in the blood?
Amount proportional to the body’s muscle mass (levels remain constant)
Which test is more sensitive? Serum creatinine or BUN
Serum creatinine
What do increased level of creatinine suggest?
Renal failure, chronic nephritis and urinary tract obstruction
What is BUN?
End product of protein metabolism
How is BUN formed?
In the liver from ammonia and readily excreted by the kidneys
What does BUN reflect? (2)
Protein intake and renal excretory capacity
What does increased levels of BUN suggest? (3)
Renal dysfunction, dehydration (reduced renal blood flow) and increased protein metabolism
What do decreased levels of BUN suggest?
Severe hepatic dx, malnutrition and over hydration
What are the serum electrolytes?
Chloride (CI), Potassium (K), sodium (Na) and bicarbonate (HCO3)
What do increased levels of serum electrolytes indicate?
Acute renal failure, glomerulonephritis and renal tubular acidosis
What do decreased levels of serum electrolytes indicate?
Chronic and acute renal failure
What is tested for in urine tests? (6)
- RBC
- WBC
- Pyuria
- Proteinuria
- pH
- Specific gravity
Is hematuria normal?
Any amount of blood in urine is abnormal
What does hematuria detect?
Inflammation, tumors, pyelonephritis and calculi
What does WBCs in the urine indicate?
Inflammation, infection and tissue necrosis
What is pyuria? What does it indicate?
Pus in the urine and indicates infection
What is proteinuria?
Protein in the urine
When is proteinuria seen?
In nephritis, polycystic dx, stones and carcinoma
What does the pH refer to in the urine?
Abundance of hydrogen atoms
Acidic if levels increased
Alkaline if levels decreased
What does the formation of stones depend on?
Urine pH - important in pt with calculi
What does specific gravity measure?
Kidneys ability to concentrate urine
When is there low levels of specific gravity?
Renal failure and pyelonephritis
When are there increased levels of specific gravity?
Urine output (dehydration)
