Kidney/Urology-Exam 3 Flashcards
Describe the components of the nephron
- glomerulus. mechanically filters blood.
- proximal convoluted tubule. reabsorbs 75% of the water, salts, glucose, and amino acids.
- loop of henle. countercurrent exchange, which maintains the concentration gradient.
- distal convoluted tubule: regulating extracellular fluid volume and electrolyte homeostasis.
Urine is formed as a result of:
- glomerular filtration
- reabsorption of substances into the blood
- excretion of substances from the blood into the renal tubules
What are the structures of the glomerular membrane?
- fenestrated endothelial cell
- glomerular basement membrane
- Podocyte
Glomerular Membrane: fenestrated endothelial cell
Structure:
Network of capillaries in the
renal cortex that is covered by epithelium called Bowman’s capsule
Function:
Blood is filtered and fluid is
collected in Bowman’s capsule
Glomerular Membrane: glomerular basement membrane (GBM)
Structure:
is a ribbon-like extracellular matrix that lies between the endothelium and the podocyte foot processes (FPs)
Function:
glomerular filtration barrier. It provides a scaffold that supports the physiological function of the glomerular endothelium and podocytes.
Glomerular Membrane: podocyte
Structure:
have long foot processes called pedicles,
Function:
play an important role in glomerular function. Together with endothelial cells of the glomerular capillary loop and the glomerular basement membrane they form a filtration barrier.
4 ways of increasing GFR
- Increase glomerular capillary hydrostatic pressure
- Hormones
- nitric oxide, prostaglandin, bradykinin
- autacoids
Increase GFR by:
Increase glomerular capillary hydrostatic pressure
works by:
- increasing intravascular volume or MAP
- dilation of afferent arterioles=more blood flow
- constrict efferent arterioles=slower flow and greater blood volume
Increase GFR by:
Hormones and autacoids
works by:
-Local angiotensin II: constricts efferent arterioles>>increasing blood flow>>inc GFR
Increase GFR by:
nitric oxide, prostaglandin, bradykinin
works by:
dilate afferent arterioles >> increasing blood flow >> increasing GFR
Increase GFR by: autacoids
works by:
-Local angiotensin II: constricts efferent arterioles>>increasing blood flow>>inc GFR
4 ways of decreasing GFR
- Increased Bowman’s capsule by hydrostatic pressure
- Increase glomerular capillary colloid osmotic pressure
- Sympathetic nervous system
- Hormones
Decrease GFR by:
Increased Bowman’s capsule by hydrostatic pressure
works by:
obstruction of urinary tract (kidney stones)
Decrease GFR by:
Increase glomerular capillary colloid osmotic pressure
works by:
high protein intake and hyperglycemia
Decrease GFR by:
Sympathetic nervous system
works by:
- norepinephrine: increases sympathetic action>> constricts afferent arterioles >> dec blood flow >> dec GFR
- epinephrine (from adrenal medulla): constricts afferent arterioles >> dec blood flow >> dec GFR
Decrease GFR by:
Hormones
works by:
Denothelin (from vascular endothelium): constricts afferent arterioles >> dec blood flow >> dec GFR
Acute Kidney Inury
Definition: sudden decline in GFR, UOP and clearance of waste products and electrolytes
Onset: within a few hours or a few days
Common Etiologies: ischemia, hypoxia or nephrotoxicity.
Chronic Kidney Disease
Definition:
also known as chronic kidney failure, means a gradual loss of kidney function over time
Onset: 3 months
Common Etiologies: HTN, DM, high cholesterol, kidney infections, glomerulonephritis, polycystic kidney disease, blockage of urine (kidney stones or enlarged prostate), or long term use of NSAIDS
Pre-renal
Risk factors:
hypovolemia, hemorrhagic blood loss, loss of plasma volume, water and electrolyte losses, septic shock, cardiac failure, massive PE, stenosis or clamping of renal artery, increased intraabdominal pressure
Etiology:
•Lack of perfusion
•Hypotension, hypovolemia
•Renal blood flow
*cause of decrease blood flow into kid.
* kid injury is before the kidneys
Patho:
Decreased renal blood flow >> hypoperfusion >> decreased GFR >> increased proximal tubule Na and H2O reabsorption >> increased aldsosterone and ADH secretion >> increase distal tubule Na and H2O reabsorption >> oliguria
Intra-renal
Risk factors:
acute tubular necrosis, glomerulopathies, acute interstitial necrosis (tumors or toxins), vascular damage, malignant hypertension, vasculitis, coagulation defects, renal artery/vein occlusion, bilateral acute pyelonephritis
Etiology: a tubular, glomerularnephritis, or interstitial area issue. Cant filter blood properly and cells are damanaged that reabsorption and secretion is effected
- Acute tubular necrosis (nephrotoxins) caused by ischemia most common cause of intrarenal AKI; happens a lot after surgery and severe sepsis
- glomerulonephritis
- Acute insterstial nephritis ( can be d/t medications)
Patho: reanal tubular injury >> cast formation >> intratubular obstruction >> increased intratubular pressure >> tubular back leack >> decreased GFR >> oliguria
Post-renal
Risk factors:
Obstructive uropathies (usually bilateral), ureteral destruction (edema, tumors, stones, clots), bladder neck obstruction (enlarged prostate), neurogenic bladder
Etiology:
Urinary obstruction
Urine is unable to drain and system
“backs up”
Patho:
bilateral obstruction to urine flow >> increase intraluminal pressure >> release of inflammatory mediators and vasscular endothelial cell injury >> renal vasoconstriction >> cellular/interstitial edema >> decreased GFR >> oliguria
CKD stage I
Severity: mild kidney damage
GFR: 90% ore more
Progression:
Symptoms: no specific symptoms, but kidney function can slowly decline; high bp, swelling in legs, UTIs, abnormal urine test
CKD stage II
Severity: mild loss of kidney function
GFR: 60-89%
Progression:
Symptoms: no specific symptoms, but kidney function can slowly decline; high bp, swelling in legs, UTIs, abnormal urine test
CKD stage III
Severity: mild to severe loss of kidney function
GFR: 30-59%
Progression:
Symptoms: changes in urinations, swelling hands and feet, weakness/fatigue, dry/itchy skin, back pain, muscle cramping
CKD stage IV
Severity: severe loss of kidney function
GFR: 15-29%
Progression:
Symptoms: anemia, decreased appetite, bone disease, abnormal levels of phosphorus, calcium, vitamin D
CKD stage V
Severity: kidneys can no longer keep up with removing waste products and extra water. This is called kidney failure. No cure, but treatment options-HD
GFR: <15%
Progression:
Symptoms: Uremia, fatigue, SOB, N/V, abnormal thyroid levels, swelling in hands/legs/eyes/lower back, lower back pain
Polycystic Kidney Disease
Etiology: Autosomal dominant kidney disorder
Patho:Production of polycystins >> change epithelium growth creating cysts >> obstruct and destroy renal parenchyma
*Cysts may occur in other organs
Manifestations: High BP, back or side pain, blood in urine, fullness in abd, increase size of abd due ENLARGED KIDNEYS, headaches, kidney stones, kidney failure
Hemolytic Uremic Syndrome
Etiology: most common cause of community acquired AKI in CHILDREN; caused by E. COLI (shiga toxin)
Patho: results in the destruction of blood platelets (cells involved in clotting), a low red blood cell count (anemia) and kidney failure due to damage to the very small blood vessels of the kidneys.
Manifestations: Abdominal pain, BLOODY DIARRHEA a, fever,
Macroangiopathic hemolytic anemia (schistocytes), thrombocytopenia, and systemic microvascular clots that can clog the glomeruli >> AKI
Prostate Hypertrophy
Etiology: Obstructive process overdistension of bladder hydronephrosis
Patho:May be “benign” or cancer
“Benign” r/t imbalance between androgens and estrogens with increased age
Cancer linked to males with family history of BRCA1 and BRCA2 breast cancer
Manifestations: Overflow incontinence, frequency, UTI
Functions of Kindeys
- excrete metabolic waste products (urea, creatinine, drugs, and hormone metabolites)
- regulate water and electrolyte balance
- regulate arterial blood pressure (renin-angiotensin-aldosterone system – RAAS)
- regulate acid base balance
- erythrocyte production (erythropoietin)
- I,25-dihydroxy vitamin production (calitriol)
- glucogenesis
Cortex
outer portion of kidney
Medulla
inner portion of kidney
Renal pyramids
organized tissue in the medulla that communicates with the renal pelvis
Minor and major calyx
collect urine made by the kidneys and lead to the renal pelvis >> ureters >> bladder
Nephrons
- functional unit of the kidney located in the cortex and medullar
- cannot be regenerated
Glomerulus
tuft of gomerular capillaries
- site where fluid is filtered from the blood which creates a filtrate which enters the tubule
- network of capillaries in renal cortex
- blood is filtered and fluid is collected in Bowmans’ capsule
Tubule
tube in which filtrate is processed into urine
what controls the rate of filtration in the glomerulus?
vascular tone of afferent and efferent arterioles
Tubule system
Bowman’s capsule >> proximal
tubule >> loop of Henle
[descending (thin) and ascending
(thick) limbs] >> macula densa >>
distal tubule >> collecting tubules
>> 8-10 collecting tubules
combine to medullary collecting
tubule >> collecting duct >> renal
pelvis