URINARY - POWERPOINT Flashcards
normal kidney length? width? thickness?
9-12 cm long
5 cm wide
2-5 cm thick
The urinary system consists of:
2 kidneys 2 ureters urinary bladder urethra
true or false?
the kidney is a retroperitoneal; located posterior to the peritoneum
true
what organs are in the peritoneal cavity (intraperitoneal)?
stomach, liver, spleen, GB
what organs are in the retroperitoneum?
(SAD PUCKER)
S- suprarenal (adrenal) glands
A- aorta/IVC
D- duodenum (2nd & 3rd segments
P- pancreas
U- ureters, urinary bladder
C- colon
K- kidneys
E- esophagus
R-rectum
retroperitoneal
retroperitoneal
Know this diagram
know this diagram
Average size of Kidney
What is the average length and weight of the kidney
average length: 11 cm
weight: 130-159 g
(depends on age, sex, body habitus and hydration)
The kidneys are paired reddish brown organs with ________lateral border, ______ medial border (hilus where blood and lymph vessels and nerves exit and enter )
convex; concave
true or false?
Both kidneys move downward approximately 1 inch w/ inspiration.
true
true or false?
the right kidney sits lower than the left
true
why is the kidney cortex darker than the inner medulla?
because of increased blood perfusion
the Inner surface of the kidney medulla is folded into projections called pyramids. where do the pyramids empty into?
the renal pelvis
where are the arcuate arteries located? and what do they seperate?
Arcuate arteries are located at the base of the pyramids.
they separate the medulla from the cortex
true or false?
Numerous collecting tubules bring the urine from its sites of formation in the cortex to the pyramids.
true
what are the functional uits of the kidney?
renal tubules or nephrons
what is the arrow pointing to in this normal kidney?
Junctional Parenchymal Defect
- Triangular, echogenic area typically located anteriorly and superiorly.
- Result of partial fusion of two embryonic parenchymal masses called renunculi during normal development.
The liver is ______ to kidney
hyperechoic
(arrow is pointing to pyramid filled w/ urine)
A vertical indentation on the medial surface of each kidney?
hilum
anteriorly to the hilum, the ______ is positioned. In the middle is the _____ artery. Posteriorly to the hilum, is the ____
renal v; renal artery; ureter
true or false
the lymphatics and nerves exit and enter the hilus into the sinus here at the hilum
true
What are the kidneys 3 layers of supportive tissue?
- Fibrous inner renal capsule: True Capsule
- Perirenal fat (middle layer)
- Gerota’s fascia (outer) anchors in place
What are the 3 distinct regions of the renal parenchyma?
- Cortex: from outer capsule in to the pyramids
- Medulla: contains pyramids and sinus fat
- Pelvis: large cavity medial to hilus, continuous w/ ureter, divides into major calyces which further divide into minor calyces
true or false?
in the renal medulla, Hypoechoic pyramids are separated by bands of intervening parenchyma that extend toward the renal sinus.
true
true or false?
Pyramids are uniform in size, shape (triangular), and distribution.
true
Apex of the pyramid points toward the ______ .
Base lies adjacent to the _____ _____.
sinus; renal cortex
in the renal hilum:
______ _______lie alongside the pyramids.
______ _______lie at the base of the pyramids.
Interlobar arteries; Arcuate vessels
Renal Pelvis/Ureter:
-
Renal Pelvis of the Ureter
- Upper expanded end of the ureter
- Divides into two or three major calyces
- Each major calyx divides further into two or three minor calyces
-
Renal Papilla
- Apex of a medullary pyramid
- Indents each minor calyx
Renal Pelvis/Ureter:
-
Renal Pelvis of the Ureter
- Upper expanded end of the ureter
- Divides into two or three major calyces
- Each major calyx divides further into two or three minor calyces
-
Renal Papilla
- Apex of a medullary pyramid
- Indents each minor calyx
Relational anatomy (read these while looking at diagram)
-
Anterior to the right kidney
- Right adrenal gland and liver
- Morison’s pouch
- Second part of the duodenum
- Right colic flexure
-
Anterior to the left kidney
- Left adrenal gland
- Spleen, stomach, and pancreas
- Left colic flexure
- Coils of jejunum
-
Anterior to the right kidney
- Right adrenal gland and liver
- Morison’s pouch
- Second part of the duodenum
- Right colic flexure
-
Anterior to the left kidney
- Left adrenal gland
- Spleen, stomach, and pancreas
- Left colic flexure
- Coils of jejunum
What lies anterior to the left kidney?
What lies posterior to the left kidney?
Anterior to left kidney: left adrenal gland, spleen, stomach, pancreas
Post. to Lt. kidney: diaphragm, psoas muscle, quadratus lumborum muscle
What lies anterior to the right kidney?
what lies posterior to the right kidney?
anterior to right kidney: right adrenal gland, 2nd part of the duodenum
posterior to right kidney: diaphragm, psoas & quadratus lumborum muscle
the renal medulla is made of hypoechoic ______ in a uniform pattern, which are seperated by bands of parenchyma that extends towards the renal sinus
pyramids
true or false?
morrisons pouch is located in the right posterior subhepatic space anterior to the right kidney and posterior to the right lobe of the liver
true
the renal sinus is the most echogenic part of the kidney.
What does the renal sinus include?
The renal sinus includes:
calyces, renal pelvis, renal vessels, fat, nerves, and lymphatic channels
true or false?
NEPHRON is basic histological and functional unit of kidney
Each kidney has > 1 million
true
Each nephron has a:
renal _____ : glomerulus & glomerular capsule
Blood is filtered in the renal ______
and a
renal _____ (loop of Henle)/vasculature
corpuscle; corpuscle
tubule
true or false?
Filtered fluid passes through the renal tubule. In the tubule:
- substances needed: are returned to the blood.
- substances not needed: (Waste products, excess water, and others) pass into the collecting ducts as urine.
true
what are the functions of the nephrons?
- Control blood concentration and volume by removing solutes/ water
- Controls blood pressure
- Renal arteries carry 25% of cardiac output to kidneys
- Help regulate blood pH
- Remove toxic wastes from blood
The ureters are approx. ___ long tube.
the proximal end is expanded and continuous w/ the renal ____
25 cm; pelvis
where does the renal pelvis lie?
Renal pelvis lies within the hilum of the kidney and receives major calyces.
Ureter emerges from the _____ of the kidney and runs ______ downward behind the parietal peritoneum along the psoas muscle.
hilum; vertically
true or false?
the ureters are not routinely visualized from the ureteropelvic junction (at hilum of kidney) to the bladder (uretero-vesicle junction) UNLESS it is dilated by fluid
true
where can constriction of the ureter occur?
constriction of ureter can occur at 3 areas:
- where ureter leaves renal pelvis
- kinking can occur across pelvic brim
- where it pierces the bladder wall
what is this congenital anomaly of the ureter:
ureteral narrowing as a result of fibrosis is a comon form of ureteral stricture
stricture
other causes of stricture:
- inflammatory disease, tuberculosis, localized periureteral fibrosis, impacted ureteral stone, schistostomiasis, iatrogenic ureteral injury, or radiation therapy.
- amyloidosis, adjacent malignancies, metastases, extrinsic compression caused by primary retroperitoneal tumors, enlarged lymph nodes, and medial lower pole renal masses.
what are some other causes of ureteral stricture?
- Ureteral strictures may also result from
inflammation tuberculosis localized periureteral fibrosis
impacted ureteral stone schistostomiasis,
iatrogenic ureteral injury__radiation therapy.
- Other causes of ureteral stricture include:
amyloidosis adjacent malignancies__metastases
extrinsic compression caused by: primary retroperitoneal tumors,
enlarged lymph nodes, & medial lower pole renal masses.
urinary bladder facts
- 3 openings
- elastic transisitional epithelium
- anechoic when full of urine
- wall thickness: 3-6 mm
- ureteral jets
- Large muscular bag
- 3 openings
- 2 in posterior for ureters to enter
- 1 anteriorly located for urethra to exit
- Elastic transitional epithelium (stretches)
- Appears anechoic when filled with urine
- Wall thickness 3-6 mm depending upon distention
- Should see ureteral jets filling bladder
Inflammation of bladder:
cystitis
Bladder Calc
what is the urethra?
urethra is a membranous tube that exits the body, and has internal and external sphincter to control urine output
- Not routinely visualized sonographically
- Terms that relate to urethra:
- Stricture
- Urethritis- inflammation
- Dysuria-difficult urination-painful urination (difficult)
true or false?
Renal arteries comes off of the medial and lateral aspect of the aorta and enter the kidney at the hilus
true
Renal arteries enter the hilus _____ to the renal veins
RRA is longer than left and travels________ to the IVC. (retrocaval)
LRV courses ______ to the aorta
posterior; posterior; anterior
true or false?
Vascular supply to the kidney is through the main renal artery.
true
Renal artery divides into ____ primary branches: a larger ____ artery and a smaller ______ artery
- These arteries break down into:
- Segmental arteries
- Interlobar arteries
- Arcuate arteries
2; anterior; posterior
- Renal artery divides into two primary branches: a larger anterior artery and a smaller posterior artery
- These arteries break down into:
- Segmental arteries
- Interlobar arteries
- Arcuate arteries
how many veins join to form the main renal vein?
where does the main renal vein emerge from?
where does the renal vein drain into?
- Five or six veins join to form the main renal vein.
- The main renal vein emerges from the renal hilus, anterior to the renal artery.
- The renal vein drains into the lateral walls of the IVC.
Where do lymphatic vessels enter the kidney and what do they follow?
Where do lymphatic nerves originate and how are they distributed
- lymphatic vessels enter at the kidney hilum, and follow the renal artery to the lateral aortic lymph nodes near the origin of the renal artery.
- Nerves originate in the renal sympathetic plexus and are distributed along the branches of the renal vessels
where is the urinary system located and what is it made of?
Two kidneys: remove wastes from the blood and produce urine
Two ureters: act as tubal ducts leading from the hilus of the kidneys and drain into the urinary bladder
Bladder: collects and stores urine, which is eventually discharged through the urethra
Urinary System
- Located in the retroperitoneum (posterior to peritoneum)
- Two kidneys: remove wastes from the blood and produce urine
- Two ureters: tubal ducts from hilus of the kidneys to the urinary bladder (drains the kidneys)
- Bladder: collects and stores urine, which is eventually discharged through the urethra
function of the urinary system?
- Removing waste: excretion
- Regulating fluid and electrolytes in blood
- 1100 -1200 ml of blood pass through each minute
- 180 liters ( 45 gal.) of blood are processed each day
- Excrete urine
(removing waste and regulating composition of blood
true or false?
Kidneys adjust the amounts of water and electrolytes leaving the body so that these equal the amounts of substances entering the body.
true
Formation of urine involves three processes:
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
what is excretion and why is it important? what other organs have excretion functions?
- Excretion: process of separating and removing substances harmful to the body
- waste products, produced by cellular metabolic activity, may reach toxic levels if not excreted from the body.
- Skin, lungs, liver, large intestine, and kidneys have excretion functions.
what are the main waste products?
Main waste products: Water, carbon dioxide, & nitrogenous wastes (urea, uric acid, and creatinine)
explain how waste products are broken down?
- Nitrogen is from amino acids and nucleic acids.
- Amino acids break down in liver (N containing amino group removed) then converted to ammonia, then converted chemically to urea
- urea and uric acid- carried away from liver to kidneys by vascular system
- creatine is a nitrogenous waste - made frm phosphocreatine in muscles
what are the 10 lab tests for renal disease?
- Urinalysis
- Urine pH
- Specific gravity
- Blood
- Hematocrit
- Hemoglobin
- Protein
- Creatinine clearance
- Blood urea nitrogen (BUN)
- Serum creatinine
______ is the presence of blood cells in the urine; it can be associated w/ early renal disease.
hematuria
______ may be present when inflammation, infection or tissue necrosis originates anywhere in the urinary tract
leukocytes
_____ is the concentration of urea nitrogen in blood and is the end product of cellular metabolism
BUN ( blood urea nitrogen)
an elevation in BUN indicates renal impairment
true or false?
the renal arteries are lateral branches of the aorta located inferior to the SMA
true
true or false?
In the kidney, the upper expanded end of the ureter (renal pelvis), divides into two or three major calyces, each of which divides further into 2 or 3 minor calyces
true
true or false?
the renal corpuscle is made of a network of capillaries called the glomerulus, which is surrounded by a cuplike structure (Bowman’s capsule). blood flows into the glomerulus throush a small afferent arteriole and leves the glomerulus throush an efferent arteriole
afferent- carrying to
efferent - carrying away
describe urinalysis (lab test for renal disease)
Urinalysis: detects urinary tract disorders , essential w/ impaired or no renal function
Acute infection causes hematuria or pyuria
- Hematuria = blood in urine
- Pyuria= pus in urine (infection)
describe Urine pH lab test for renal disease
Urine pH: - important w/ diseases such as bacterium or renal calculi.
-
pH is the abundance of hydrogen ions
- if ↑ H+ ions= acidic
- if ↓ H+ ions = alkaline
- Acidic -assoc. w/calculi
- Alkaline -assoc. w/ chronic renal failure, renal tubular acidosis
describe specific gravity (lab test for renal disease)
Specific gravity: detects ability to concentrate urine
↑ sweating ↓ fluid intake, diahrea = less urine–> ↑ specific gravity
very ↓ : renal failure, glomerular nephritis, pyleonephritis
describe blood (lab test for renal disease)
RBC in urine; associated w/ early renal disease
associatied w/: renal trauma, neoplasm, calculi, pyelonephritis, glomerular or vascular inflammatory process
WBC -inflammmation, infection, or necrosis is in the urinary tract
describe hematocrit (lab test for renal disease)
hematocrit - is ratio of plasma to packed cell volume in bld (%of blood made of RBC)
decreased hematocit: acute hemorrhagic processes secondary to disease or blunt trauma
describe hemoglobin (lab test for renal disease)
hemoglobin - present when extensive damage of functioning erythrocytes occur.
this injures the kidney, may cause acute renal failure
describe protein (lab test for renal disease)albumin
- healthy kidneys have filters that remove waste; keep large cells(RBC, protein). when filters are damaged protein leaks into urine
w/ glomerular damage, proteins (albumin) are excessively filtered and leak into urine (= ↓ serum albumin levels)
albuminuria common w/: benign and malignant neoplasms, calculi, chronic infection and pyelonephritis
describe creatine clearance (lab test for renal disease)
compares creatine in blood and urine.
accurate for determining glomerular filtration rate. (determines how well the kidneys are working)
decrease indicates renal dysfunction (because creatine levels are always constant; only decreased renal function can cause this)
describe BUN (lab test for renal disease)
BUN is end product of cellular metabolism.
Urea- form in liver when protein is broken down–>to kidney in blood to be excreted as urine
↑ associated w/: impaired renal function, increased protein catobolism
describe serum creatine (lab test for renal disease)
renal dysfunction results in ↑ serum creatine levels (healthy kidneys remove creatine from blood)
Serum Creatinine: more specific than BUN when determining renal impairment
important labs to remember:
- Creatinine clearance: decrease indicates renal dysfunction
- BUN: elevation indicates renal impairment
- Serum Creatinine: more specific than BUN
explain the related imaging benefits and when it is used.
(Plain film & x-ray, IVP, NCCT, MRI)
- Plain film x-ray and US: noninvasive, inexpensive, for pt. with Hx of stones
- IVP: intravenous pyelogram for renal colic ( flank pain)
- NCCT: noncontrast CT for pt. with no history of calc’s
- MRI: for diagnosing renal disease
true or false?
the left renal vein goes from the renal sinus, anterior to the aorta, and posterior to the SMA to join the IVC
true
true or false?
the right renal artery is sen as a circle coursing posterior to the IVC in the saggital plane
true
is US helpful in evaluating organ function?
no
true or false?
hemoglobin is present in urine when extensive damage of the erythroctes occurs. this condition injures the kidney an may cause acute renal failure
true
true or false?
outside the fibrous capsule is a covering of perinephric fat
true
true or false? metabolic waste must be excreted quickly to prevent toxic quanties of homeostasis
true
true or false? Renal Sonography:
- Demonstrates acoustic properties of a mass
- Delineates abnormal lie of kidney
- Possible mass displacing kidney
- Determines if hydronephrosis is present
- If so, check for stones
- Image congenital anomalies
- Define perirenal fluid collections, abscesses, hematomas
- Determine renal size and parenchymal details
- Detect congenital anomalies
- Check for dilated ureters (distal obstruction)
true Renal Sonography:
- Demonstrates acoustic properties of a mass
- Delineates abnormal lie of kidney
- Possible mass displacing kidney
- Determines if hydronephrosis is present
- If so, check for stones
- Image congenital anomalies
- Define perirenal fluid collections, abscesses, hematomas
- Determine renal size and parenchymal details
- Detect congenital anomalies
- Check for dilated ureters (distal obstruction)
what is the sonograhic technique used for renal US
- Prep: no prep unless bladder is to be imaged
- Bladder
- Examine kidneys in 2 planes
- Position: supine, decubitus
- Equipment – choose according to body habitus
The kidney cortex is ______ to the liver.
the least echogenic part of the kidneys are the _____. when filled w/ urine they appear ______.
Medullary sinus fat is _____. (the most echogenic part of kidney)
hypoechoic;
medullary pyramids; hypoechoic
echogenic
what is suspected if 2 seperate collections of renal sinus fat are identified?
double collecting system should be suspected.
when may renal detail be obscured?
Renal detail may be obscured if the patient has hepatocellular disease, gallstones, rib interference or other abnormal collection between the liver and kidney.
normal kidney images
normal kidney images
renal vein and artery
renal vein is anterior to the artery
right renal artey
you can see tail of pancreas (calipers)
what is the only vessel to run posterior to the IVC? RRA
left renal artey flows form the lateral wall of teh aorta to the central renal sinus
right renal vein (true mid)
- true mid when you can see vessels going in
RRV extends from the central renal sinus directly to the IVC
left renal vein
LRV flows fromthe central renal sinus anterior to the aorta and posterior to the SMA, to join the IVC
what are the 7 normal variants of the kidney?
- Dromedary Hump
- Junctional parenchymal defect
- Column of Bertin
- Lobulations
- Horseshoe Kidney
- Duplicated Kidney ( double collecting System) or duplicated ureter
- Agenesis
describe the variant, columns of Bertin
Prominent invaginations of the cortex at varying depths within the medullary (medulla) of the kidneys
Hypertrophied columns of Bertin contain renal pyramids; they may be difficult to differentiate from an avascular renal neoplasm.
Columns are more exaggerated in patients with complete or partial duplication.
columns of Bertin
- Prominent invaginations of the cortex at varying depths within the medullary substance of the kidneys
- Hypertrophied columns of Bertin contain renal pyramids; they may be difficult to differentiate from an avascular renal neoplasm.
- Columns are more exaggerated in patients with complete or partial duplication.
- Prominent invaginations of the cortex at varying depths within the medullary substance of the kidneys
- Hypertrophied columns of Bertin contain renal pyramids; they may be difficult to differentiate from an avascular renal neoplasm.
- Columns are more exaggerated in patients with complete or partial duplication.
describe the variant Dromedary Hump
Dromedary Hump (camel hump)
- Shape of left kidney is affected by the spleen.
- A bulge of cortical tissue can occur on the lateral border of the kidney; may resemble a renal neoplasm; more common in left kidney.
- On sonography, the echogenicity is identical to the rest of the renal cortex, and a renal pseudotumor needs to be considered.
describe the normal variant -junctional parenchymal defect
Junctional Parenchymal Defect
- Triangular, echogenic area typically located anteriorly and superiorly.
- Result of partial fusion of two embryonic parenchymal masses called renunculi during normal development.
- triangular shaped echogenic area in the upper pole of the renal parenchyma
- (notch in the cortex and renal fat fills it in)
true or false? the bladder wall may be 3- 6 mm depending on the level of bladder distention
true
describe the renal varient fetal lobulation.
present in children up to age 5, seen in 51% of adults
Surfaces of the kidneys are generally indented in between the calyces, giving the kidneys a slightly lobulated appearance. (lumpy and bumpy)
describe the renal variant duplex collecting system
double collecting system (duplex kidney)
corticol tissue goes through and sperates
describe the renal variant sinus lipomatosis
sinus lipomatosis: a moderate amount of fat in the renal sinus, with parenchymal atrophy
(larger hyperechoic sinus fat, thin walled cortex
describe the renal variant extrarenal pelvis
- Normal renal pelvis is triangular structure.
- Axis points inferiorly and medially.
- Extrarenal pelvis tends to be larger, with long major calyces.
- Pelvis appears as a central cystic area that is either partially or entirely beyond the confines of the bulk of the renal substance.
does polycystic kidney affect function?
yes
what are congenital anomalies and how are they classified?
can be seen in utero and in infants. Classified 3 ways:
1. amount of renal tissue/size
- number
- Agenesis = absence
- Dysgenesis= defective embryonic development
- supernumerary= complete duplication
-
position/form/orientation
* Ectopic, horseshoe
what is sinus lipomatosis?
a condition characterized by deposition of a moderate amout of fat in the renal sinus w/ parenchymal atrophy
what is renal hypoplasia?
incomplete development of the kidney, usually w/ less than 5 calyces
true or false?
incomplete or partial duplication is the most frequently occurring congenital anomally in the neonate. duplication consists of 2 collecting systems, and 2 ureters, with a single ureter entering into the urinary bladder
true
true or false?
complete duplication is the rare condition of a duplex collecting system. 2 seperate collecting systems, each w/ a ureter that enter the bladder. sometimes a double ureter, the ureter from the upper pole opens below and medial to the one from the lower pole (rule of Weigert-Meyer)
list the 9 congenital renal anomalies
- Solitary kidney
- Renal hypoplasia
- Pseudotumor
- Bifid renal pelvis
- Incomplete duplication
- Duplex collecting system
- Renal ectopia, pelvic kidney
- Crossed renal ectopia
- Horseshoe kidney
true or false?
Kidney migration from pelvis to abdomen after approx. 5 yrs. of life
true
what is pronephros?
fore kidney -non functioning
what is mesonephros?
mid kidney - partial functioning
what is metanephros?
permanent kidney- fully functional
true or false?
in males persists (Wolffian) develops epidymus, ducts deferens, ejaculatory ducts. in females develops into paramesonephric duct (Mullerian) which forms uterus and vagina
true
true or false? the pelvic kidney (sacral kidney) is the most common renal ectopia and should not be misdiagnosed as a pelvic tumor
true
ectopic: pelvic kidney facts
- also called the sacral kidney - most common renal ectopia and should not be confused as a pelvic tumor
- renal ectopia (ectopic kidney) describes a kidney that is not located in its usual position, the renal fascia
image: full bladder; kidney is posterior to the bladder
true or false? a horseshoe kidney is the most common anomally of renal fusion. fusion of the lower poles occurs in 96% of cases, with ureters passing anterior to the renal parenchyma and variations of arterial land venous blood supply
true
a horseshoe kidney usually fuses at the lower pole. associated w/ improper ascent and malrotation. inferior poles lie more medial, w/ isthmus crossing anterior to the aorta
pathology of the urinary system includes:
- Renal cystic disease
- Hematoma
- Abscess
- Nephritis
- Necrosis
- Renal failure
how are renal masses classified w/ sonography?
cystic, solid, or complex
what is the criteria for a simple cyst?
Cystic mass
- Smooth, thin, well-defined border (walls)
- Round or oval shape
- Sharp interface between the cyst and renal parenchyma
- No internal echoes (anechoic)
- Increased posterior acoustic enhancement
(anechoic, thin smooth walls, posterior acoustic enhancement
complex renal cyst characteristics
- May contain septations, thick walls, calcifications, internal echoes, and mural nodularity.
- Considered malignant until proven benign
- Internal echoes often result of protein content, hemorrhage, and/or infection.
- Any irregularity at the base of the cyst should be considered a malignant growth.
- If septa is thicker than 1 mm with vascularity on color or power Doppler, the lesion is presumed malignant.
solid mass characteristics
- Irregular borders
- Poorly defined interface between the mass and kidney
- Low-level internal echoes
- Weak posterior border (because of the increased attenuation of the mass)
- Poor through-transmission
true or false? an extrarenal pelvis appears as a central cystic region that may partially or entirely extend beyond the confines of the bulk of the renal sinus
true
true or false? an angiomyolipoma is the most common benign renal tumor. it is composed of fat, muscle, blood vessels
true or false? in sinus lipomatosis, the abundant fibrous tissue may cause enlargement of the sinus region w/ an increase in echogenicity
true
A
glomerulus
B
Ascending loop
C
Capsule
D
Cortex
E
Minor calyces
F
Major Calyyx
G
Renal artery
H
Renal Vein
I
pelvis
J
ureter
K
Medullary rays
L
perinenephric fascia
M
perinephric fat
N
interlobar artery
O
renal papilla
P
pyramid
Q
collecting tubule
R
descending loop
