Structure and Function of the Kidney and Urinary Tract Flashcards
Where are the Kidneys located?
In the Retroperitoneum, behind the abdomin, protected by lower ribs
How much blood supply do the kidneys receive from the heart?
~25%
What are the Kidneys function?
- filter blood into urine, excreting waste products
- regulation of water, salt, calcium, phosphorus, blood pH, and others
- Endocrine function: Renin, Erythropoietin, regulates Vitamin D metabolism
How much blood do the kidney’s filter each day?
1700 L per day, to create 1 L of urine
What does Renin do?
regulate blood pressure
What connects the Kidneys to the Bladder?
Ureters
What are the Kidneys supplied by?
The renal artery
What is the outflow of blood from the Kidneys supplied by?
the renal vein
What is the Hilum?
Contains renal artery, renal vein, and ureter
What is the Cortex?
Contains glomeruli and tubules
What is the Medulla?
- Contains collecting system (renal pyramids)
- from which urine drains into renal calyces, renal pelvis, and ureter
What is the Ureter?
a muscular tube that connect the kidneys to and enters the bladder
What is the Bladder?
a hollow organ that is a reservoir for urine
What is the Urethra?
a fibromuscular tube from the bladder to the exterior
What are the main components of the Cortex?
- Glomeruli
- Tubules
- Interstitium
- Blood vessels
What is the Glomerulus? (4)
- A functional unit of filtration
- tuft of capillaries, with afferent (inward) and efferent (outward) arterioles
- Capillaries are lined by glomerular basement membrane (GBM)
- surrounded by double lining of epithelial cells, called Bowman’s capsule
What is the Bowman’s space?
The space between the epithelial layers, also called urinary space
What do the capillary endothelial cells contain?
Fenestrations (sieve-like holes)
What do Fenestrations do?
- allow for passage of fluid and small molecules (water, electrolytes)
- restricts passage of larger molecules (proteins) and blood cells
What surrounds the endothelial cells?
Glomerular basement membrane
What does the Glomerular basement membrane do?
Aids in filtrations, as physical barrier and charge barrier
What are the Glomerular basement membrane and the endothelial cells surrounded by together?
Podocytes, which contain foot processes with filtration silts
Where does blood in the capillary space pass through?
- fenestrations
- glomerular basement membrane
- podocyte filtration slits
What occurs with the left over fluid in the urinary space?
It needs to be concentrated and therefore enters the proximal convoluted tubule
What abilities does the Proximal Convoluted Tubule have?
- resorptive
- secretory
Where does the fluid go after the Proximal Convoluted Tubule?
The Loop of Henle
- creates a concentration gradient in the kidney
- causes further reabsorption of water and salt
Where does fluid go after the Loop of Henle?
Distal convoluted tubule, and then collecting ducts
How many nephrons are in each kidney?
1-1.5 million
How does urine travel in the body?
- emptied from the collecting ducts into the renal pelvis
- travels down the ureter into the bladder
- exits via the urethra
What are the renal pelvis, ureter and bladder all lined with?
Urothelium, which has special properties that allows the bladder to expand
What is Renal Cell Carcinoma?
- Most common malignancy of the kidney
- about 3% of adults
- Usually in their 50-60s
- More common in males 2:1
What are the risk factors for Renal Cell Carcinoma? (8)
- smoking
- Obesity
- Hypertension
- Unopposed estrogen
- Chemical exposures
- Chronic kidney disease
- Acquired cystic disease
- Rarely related to syndrome/familial
What are the signs and symptoms of Renal Cell Carcinoma? (5) or (8)
Classic Triad:
- flank pain
- palpable mass
- hematuria
Fever
Feeling unwell
weakness
weight loss
What is the treatment of Renal Cell Carcinoma?
Surgery (nephrectomy)
What is the most common subtype of Renal Cell Carcinoma?
Clear Cell Renal carcinoma
Macroscopically how does Clear Cell Renal Carcinoma look like?
Yellow with areas of hemorrhage (red)
What is Urothelial Carcinoma?
- most common malignancy of the bladder
- arise from urothelium (may occur in renal pelvis or ureter)
- more common in males (3:1)
- more common in older pts (50-80s)
- more common in developed nations, urban dwellers
What are the Risk factors for Urothelial Carcinoma? (5)
- smoking
- industrial exposure to some chemical compounds
- Parasitic infection
- drugs (long term analgesics, heavy long term exposure to immunosppressive drugs)
- Irradiation
What are the signs and symptoms of Urothelial Carcinoma?
- painless hematuria
- urinary frequency
- burning with urination
- urinary urgency
What are the characterization of Low Grade Urothelial Carcinoma? (6)
- slow growing
- papillary
- minimal atypia
- frequently recur
- usually not aggressive
- rarely invasive
What are the characterization of High Grade Urothelial Carcinoma? (6)
- More aggressive
- may be flat or nodular
- high recurrence rate
- more atypical
- more likely to invade
- may metastasize
What is the treatment for low grade, noninvasive or minimally invasive Urothelial Carcinomas?
- local excision
- intravesical chemotherapy or BCG
What is the treatment for high grade, or muscle invasive Urothelial tumours?
Cystectomy (resection of the bladder)
What are the types of kidney infections?
- acute Pyelonephritis
- chronic Pyelonephritis
What is Acute Pyelonephritis?
- bacterial infection of the kidney, usually associated with UTI spreading
What are the symptoms of Acute Pyelonephritis?
- fever
- flank/back pain
- nausea/vomiting
- associated bladder infections symptoms: pain with urination, urinary frequency, urgency
What are the risk factors for Acute Pyelonephritis? (7)
- urinary tract obstruction
- instrumentation
- vesicoureteral reflux
- pregnancy
- gender and age (often young females)
- diabetes
- immunosuppresion/immunodeficieny
How is Acute Pyelonephritis diagnosed?
by urine culture
How is Acute Pyelonephritis treated?
usually resolves with antibiotics
What is Chronic Pyelonephritis?
Chronic inflammation and scarring of the kidney
What are the causes of Chronic Pyelonephritis? (3)
- reflux
- long term obstruction
- recurrent infection
What are the different types of Renal Failure?
- Acute
- Chronic
What is Acute Renal Failure?
- occurs over hours to days
- can be reversible if underlying cause is treated
What is Chronic Renal Failure?
- occurs over prolonged time
- progressive, irreversible destruction of kidney
- loss of function
- may have no symptoms until later in disease course
What is Acute Pre-Renal Failure?
a process that results in decreased blood flow to the kidney
What are the Pre-Renal causes for Acute Renal failure?
- decreased blood pressure (especially rapid)
- dehydration
- severe hemorrhage
What are the causes of Acute Renal Failure? (6)
- drugs
- toxins
- infections
- inflammation
- ischemic acute tubular injury
- acute glomerulonephritis
What is Acute Post-Renal Failure?
Obstruction of flow of urine
What are the causes of Acute Post-Renal Failure?
Kidney stones
What are the signs and symptoms of Renal Failure? (7)
- Azotemia (increased blood urea niitrogen (BUN) and Creatinine)
- Edema
- Electrolyte disturbances
- Metabolic acidosis (low blood ph)
- anemia (low hemoglobin)
- hypertension
- bone disease
What is End Stage Renal Disease? (6)
- eventual end point of kidney diseases
- sclerosis of glomeruli
- scarring/fibrosis of interstitium
- Loss of tubules (tubular atrophy)
- Chronic inflammation
- Thickened arteries
What is the Treatment of Renal Disease?
- lifestyle modifications
- Medications
- Dialysis when kidney function declines to end stage renal disease
- kidney transplant
What is Glomerular Disease?
- damage to glomerular basement membrane; impairs filtration
- Can be divided into primary or secondary glomerulopathies
What is Primary Glomerulopathy?
affects the glomerulus alone or primarily
What causes Primary Glomerulopathy? (4)
- IgA nephropathy
- post-infectious glomerulonephritis
- membranous nephropathy
- focal segmental glomerulosclerosis
What is Secondary Glomerulopathy?
Systemic disease (affect multiple organs), which affect kidney
What causes Secondary Glomerulopathy? (3)
- diabetes
- systemic lupus erythematosus
- vasculitis
What are mechanisms of Glomerular Injury? (2)
1) Antibodies reacting in situ within the glomerulus
- bind to intrinsic glomerular antigens, or
- bind to extrinsic antigens deposited within the glomerulus
2) deposition of circulating preformed antigen-antibody complexes within the glomerulus
What are the manifestations of Nephritic Syndrome? (6)
- Hematuria
- Azotemia
- Variable proteinuria
- Oliguria
- Edema
- Hypertension
What are the manifestations of Nephrotic Syndrome? (4)
- Proteinuria (>3.5 g/day)
- Hypoalbuminemia
- hyperlipidemia
- lipiduria
What are the common causes of Acute Tubular Injury/Necrosis?
- Ischemia
- Toxic injury to tubules: endogenous agents, and exogenous agents
What is the clinical course of Acute Tubular Injury? (6)
- initial inciting event
- decreased urine output
- rise in BUN and creatinine
- Electrolyte abnormalities and metabolic acidosis
- Urine volume increases with recovery
- Outcome related to magnitude and duration of ATI
What is the Prognosis of Acute Tubular Injury?
Most pts who survive initial events recover completely
What is Atherosclerosis? (5)
- Narrowing of arteries due to plaque buildup
- leads to decreased blood flow to the kidney
- Kidney atrophy
- chronic kidney failure
- Risk of thromboembolism (clot), with renal infarct
What is Hypertension? (6)
- major cause of end stage renal disease
- leads to nephrosclerosis
- scarring of glomeruli
- chronic tubulointerstitial injury
- decrease in renal mass
- decline in renal function
What is Vesicoureteral Reflux?
When urine from the bladder enters the ureters
What is a cause of Vesicoureteral Reflux?
Anatomical defect (often congenital)
What are the complications of Vesicoureteral Reflux? (3)
- urinary tract infection, pyelonephritis
- hydroureter/hydronephrosis
- chronic renal failure (if advanced)
What are the treatment options for Vesicoureteral Reflux?
- Conservative Treatment: some cases will resolve as child grows
- surgical reimplantation of ureter
What Is Intrinsic obstruction? (5)
- lesions of urinary tract
- stones
- congenital/acquired strictures
- tumours of urinary tract
- functional disorders (often neurogenic)
What is Extrinsic Obstruction? (4)
- external compression
- pregnancy
- inflammation/scarring of surrounding organs
- tumours in surrounding organs
What are the different types of Urinary Tract Obstruction?
- acute or chronic
- partial or complete
- unilateral or bilateral
What occurs in Acute Urinary Tract Obstructions?
Often have flank pain (renal colic)
What occurs in Unilateral/partial Urinary Tract obstructions?
Asymptomatic
- unaffected kidney can maintain renal function
What occurs in Chronic Urinary Tract Obstructions?
results in chronic kidney disease
What are Urinary Tract Stones? (5)
- form in the kidneys
- men more than women
- 20-30 years
- familial predisposition
- may arise due to underlying medical condition
What are the different types of Urinary Tract Stones?
- Calcium oxalate/phosphate 70-80%
- Struvite (magnesium ammonium phosphate) 5-10%
- Uric Acid 5-10%
- Cystine 2%
What does Calcium oxalate/phosphate stones cause?
Increased calcium in blood or urine
What does Struvite (magnesium ammonium phosphate) cause?
- bacteria convert urea to ammonia, which combines with magnesium and phosphate
- large, staghorn stones
What does Uric Acid cause?
- may have hyperuricemia (patients with gout)
- low urine pH
What does Cystine cause?
Genetic defects in cystine reabsorption
What are the most important determinants for Urinary Tract Stones?
- increased urinary concentration of stone’s constituents
- exceed solubility (supersaturation)
What are other factors influencing factors of Urinary Tract Stones? (3)
- changes in urinary pH
- decreased urine volume
- presence of bacteria
What is the presentation of Urinary Tract Stones? (6)
- may be asymptomatic
- may cause severe renal colic, abdominal pain
- may cause significant kidney damage
- hematuria (blood urine)
- Predispose patient to infection
- Diagnosis aided by imaging
What is the treatment for Urinary Tract Stones?
- wait for stones to pass: drink fluids, pain management
- lithotripsy (sound waves shatter stones)
- surgical removal
