exam_3_20150304203003 Flashcards
What are the two types of nephrons?
Cortical (85%) and Juxtamedullary (15%)-juxtamedullary have longer distal tubules that extend into the medulla (lower oxygen level here)
What is the glomerulus and Bowman’s Capsule?
glomerulus is a tuft of capillaries and the Bowman’s capsule is over the glomerulus-the parietal epithelium is the outermost layer of the Bowman’s capsule
What is the visceral epithelium and podocytes of kidneys?
visceral epithelium is also called podocytes. These are cells with radiating rootlike processes, form a network of intercellular clefts called filtration slits and the foot like process are connected by proteins
Glomerular basement membrane
-negatively charged-selectively permeable network of glycoproteins and mucopolysaccharides *allow water and small solutes through *small pores and filtration slits make the glomerular basement membrane less permeable to larger molecules like proteins *the membrane repels proteins because protein molecules are negatively charged
What happens when there is a loss of the negative charge on the basement membrane of the glomerulus?
loss of negative charge or injury to podocytes causing larger pores and slits will allow protein through the glomerular basement membrane
What is the function of the mesangium?
-contains mesangium cells that have macrophages, intrinsic glomerular cells-form mesangial matrix-have contractile and proliferative function
Juxtoglomerular apparatus
contains juxtoglomerular cells-smooth muscle cells in the afferent arteriole next to the distal tubule; sense stretch; manufacture, store and release renin
What does the Macula densa cells do?
distal tubular cells nearest the glomerulussense Na content
Renal blood flow
-25% of CO-from cortex to medulla
Why is PaO2 less in the medulla?
it is less in the medulla because it goes to the cortex first. however more O2 is needed in the medulla to generate ATP for transporting substances—>makes it more susceptible to injury
What does the juxtaglomerular cells do?
assesses perfusion pressure
Autoregulation is provided by tubuloglomerular feed back by which two cells?
- macula densa=decreased Na triggers renin->afferent arteirole vasodilation and efferent arteriole vasoconstiction-increased Na= afferent arteriole vasoconstriction and efferent arteriole vasodilation2. juxtaglomerular cells=assess perfusions press ion-increased MAP (stretch) causes constriction of afferent artierole-decreased MAP stimulates renin release and afferent arteriole vasodilatation
Neural Regulation and Humoral Regulation of kidneys
SNS: vasoconstrict, renin production NO PNS innervationvasoconstriction from angiotensin II, vasopress (ADH), endothelia’svasodilation from NO, adenosine, prostaglandins, dopamine
What is the best indicator of renal function?
creatinine clearance-amount of creatinine excreted in the urine per minute -slightly overestimates GFR-Normal GFR= 120 ml/min, pregnancy 120-160 ml/min-Failure<20ml/min
Serum Creatinine and BUN for renal function
-serum creatinine is common method of estimating trending GFR (normal: 0.8-1.0)*if double then GFR is about 50% of normal and if it is 3x high then GFR is about 25% of normal-BUN: levels increase as glomerular filtration drops-about 50-60% of renal function must be lost before a significant rise in BUN occurs
Excretion of Na in kidney
normal: over 99% of filtered Na is reabsorbed and 1%
What are casts and how are the important in UA?
casts are tube shaped particles of leukoproteins of tubular epithelial cells and whatever blood cells that are in there.RBC do not pass through filtration process-So when you have Red cell casts it indicates bleeding in the tubules-white cell casts are associated with inflammatory process-epithelial cell casts indicate degeneration of the butler lumen on necrosis of the renal tubules
Terms: GF, filtrate, compensatory hyperfiltration
GF: movement of fluids from capillaries across basement membrane and to the tubules (then called filtrate)filtrate is usually free of cellular elements and essentially protein freeloss of nephrons results in compensatory hyper filtration => increased GFR per nephron
Where does the concentration of tubular fluid occur?
occurs in loop of Henle
Where does the concentration of urine occurs?
collecting duct under influence of ADH and aldosterone
What is vitamin D made from?
-made from cholesterol in our skin by the action of ultraviolet light; source of inactive vitamin D includes dietary source-inactive vitamin D is transported to the liver and converted to an inactive compound -intermediate compound is taken to kidneys and under two step process activated under influence of PTH -active vitmain D stimulates the absorption of Ca and Ph by small intestine and stimulates osteoclasts to reabsorb bone to increase Ca
Water/Na reabsorption occurs in…
proximal tubule, descending thin limb of the loop of Henle, distal tubule and collecting ducts (Cl passively follows in the ascending limb, proximal tubule and distal and collecting ducts)
Aldosterone controls water and Na absorption in the Vasopressin (ADH) secreted by hypothalamus increases reabsorption of water in the
distal tubule and collecting duct collecting duct
Final place for reabsorption…
distal tubule and collecting ducts
K reabsorption occurs in
proximal, loop of Henle, distal final excretion determined by the rate at the collecting ducts
Regulation of K excretion by kidneys is influenced by…
influenced by plasma levels, acid-base balance, plasma osmolality, aldosteroneacid-base balance (H replaced by K) (acid=^H=K ^ as it goes out of cell) decreases section (base=lowH=low K as it goes into cell and H out)increases secretion
Ca regulation of Kidneys
-mostly reabsorbed by proximal and distal-reabsorption in loop of Henle is tied to Na and K-influenced by PTH and calcitonin and acid base balance
Bicarbonate buffer system or bicarbonate conservation system
H secretion takes place in proximal tubule mostlyH secretion by tubular cells causes Na reabsorption and the H is recycle to make more bicarb when needed
Renal response to alkalosis
decrease H secretiondecrease ammonia productionincrease HCO3 production
Renal response to acidosis
increase Hproduction of ammonia to accommodate H excretionIncrease HCO3 reabsorption
What drugs can cause pre renal disorders
1 ACE inhibitors: loss of efferent vasoconstriction; when combined with decreased glomerular blood flow it will decrease GFR2 NSAIDS: inhibit prostaglandin synthesis; therefore decreased vasodilation and allows afferent vasoconstriction and decreases GFR3 vasoconstrictive drugs
Glomerular disease etiology
hereditary, secondary to other d/oor common immune mechanisms:1 circulating antigen-antibody complex disposition 2 antibodies against planted antigens in the glomerulus3 autoantibodies against normal glomerular components4 T cell mediated immunity
Glomerular injury patho
1 complement activation: neut and macs are recruited and are responsible for opsonizaiton; MAC (membrane attack complex) causes epithelial injury, swelling and loss leading to detachment of epithelium2 neut and mac: release protease that cause GBM degradation, ROS more damage, mac activate fibroblasts; secrete more cytokines to stimulate more cells to come3 increased numbers of activated T lymph and NK cells (NK and T cells release cytokines) (NK lysis of affected cells)4 platelet aggregation: activates coagulation system and fibrin5 vasodilation6 alteration in endothelium permeability, change in GBM charge, allows for greater passages of protein and RBC across membrane 7 messangial cell activate and proliferate; produces inflammation, growth factors, accumulation of ECM, activate fibroblasts; sclerosis of mesangium8 BM and glom thickening, and change in charge9 podocyte injury cause epithelium swelling, stimulates secretion of inflam mediators, podocyte foot stretch/effacement cause abnormal protein filtration and podocytes are not replaced
What happens when podocytes are affected?
loss of foot process (GBM denuding)altered membrane charge and abnormal protein filtrationeventually decreases GFR and nephron loss
What is the compensatory process of glomerular injury
compensatory hypertrophy of remaining glom-from hemodynamic changes in glom blood flow, transcapillary HTN, and filtration volume-causes injury to remaining glomeruli-inflammation-fibrosis-sclerosis of glom-inflammatory process and protein cause tubular injury and interstitial fibrosis
Acute Nephritic Syndrome and Nephrotic Syndrome manifestations
1 acute nephritic syndrome: Hematuria/RBC casts, decreased GFR, Azotemia (increased BUN, Cr), HTN, variable proteinuria (not severe), fluid and Na retention; edema2 nephrotic syndrome: increased glomerular permeability to plasma proteins characterized by proteinuria, hypoalbuminemia (hypoproteinemia), edema, hyperlipidemia and lipiduria
Why is hyperlidemia and lipiduria a result of nephrotic syndrome?
compensatory synthesis of proteins by liver
What are long term risks associated with nephrotic syndrome?
immunosuppressed because of loss of IgG, thrombotic complicates because antithrombin III deficiency and reduced levels of Protein C and S, vitamin D deficiency and hyperparathryoidism due to loss of Vitmain D binding proteinsand renal failure
Acute Glomerulonephritis etiology
usually caused by streptococcal infection and in children-deposition of immune complexes -thought that Compliment activation at C3 or alternative pathway which initiates inflammatory process -leukocytes infiltration, mesangial cells proliferate, immune complexes may be degraded or phaocytosed by leukocytes
Acute Glomerulonephritis manifestations
abrupt onset of acute nephritic syndrome, mild oliguria 7-10 days ager the infectious disease, gross hematuria, elevation of anti streptococcal antibody if present, systemic response to Il-1 and TNFa
Etiology and path of Rapidly Progessive glomerulonephritis
immune complexes deposited -proliferation of parietal cells in Bowman’s Capsule, appear as CRESCENT SHAPE, nephritic syndrome to chronic RF
IgA Nephropathy etiology and path
IgA antibodies deposited in mesangium usually IgA 1 subtype-activation of complement system; inflammatory response-mesangial cell proliferation, release of oxidants and protease, and leads to gomerulosclerosismanifestation: nephritic, hematuria, progresses to CRF
Minimal change disease
frequent cause of nephrotic syndrome in children-t-cell injury causes podocyte damage and diffuse effacement of podocyte foot processes-change in charge, proteins slip through-usually preserve renal function
Membranous nephropathy
usually older adults -usually antibody response to antigens expressed by podocytesand sometimes with other inflammatory d/o-present of deposition of immune complexes in sub epithelium along GBM; complement system activation, diffuse thickening of capillary wall, effacement of foot processes, thinkening of GBM, sclerosis-manifestations; nephrotic syndrome, end-stage RF
Chronic glomerulonephritis leads to
continued injury and obliteration of the glomerulus and marked interstitial fibrosis
Acute tubular injury (ATI) etiology
most common acute kidney inure-destruction of tubular epithelium cells -etiology: ischemia ATI, nephrotoxic ATI (drugs, NSAIDS, gentamycin, radiographic dye, poisons, rhabdomylosis)
Acute tubular injury (ATI) patho
1 ischemia: decreased perfusion>renin secretion>renal medullary hypoxia>endothelial injury>secretion of endothelin and NO and PG12>vasoconstriction>vasoconstriction2 nephrotoxic: tubule cell injury causes disturbance in blood flow>decreased NO and PG12>hypoxia and loss of polarity and adhesion of cells> sloughing of cells, cast formation, cell edema, obstruction, intratubular pressure increase and decreases GFR-altered Na reabsorption increases Na in tubule>afferent vasoconstriction and decreased GFR -damage to tubule causes leaking into interstitium> increases interstitial pressure and collapses tubule>cell damage and inflammatory>eventually irreversible cell injury and necrosis and apoptosis
Acute tubular injury (ATI) manifestations
ARFfocal/pathcy tubular cell necrosis-epithelium cell casts-fractional excretion of Na less than 99%-urine osmolality <200 (normal 200-800)(getting rid of more Na than we should)-usually affected in the proximal and thick descending (ischemia) or proximal (nephrotoxic)
Cystic Disease of Kidney
-characterized by dilation of tubular structures and cyst formation-when epith cells are unable to sense flow of urine the cells lose polarity and will start to divide uncontrollably and in all directions and form a cyst
What are cilium?
-cilium is on every tubular epith cell-regulate the growth of the kidney cells and the direction they are formed-all epith cells have polarity and cilium always forms on interior or apical side so urine passing through the tubules on its way to the bladder can flow ove the cilium and bend it in the direction of the flow-calcium channel mechanosenso at the base of the cilium senses bending-it sends Ca into cilium which signals the okay-sensing also important in directing kidney cells to grow in proper direction-gene mutations prevent cilium’s signal from reaching the cell-no longer able to sense normal flow of urine the epith cell loses is polarity and starts dividing uncontrollably in all directions to form a cyst
Polycystic kidney disease
-gene mutations will cause sustained cellular proliferation of tubular epith cell>abnormal cell differentiation> development of cystic epithelium and altered cell adhesion>production of cyst and cyst fluid>compress surrounding vasculature and other tubules>calyces pelvis-the fluid contains inflam mediators> fibrosis and enhance fluid secretion
Pyelonephritis patho and manifestations
-infection and inflammation of kidney tubules, interstitial and renal pelvis-acute: patchy interstitial inflammation, intratubular aggregates of neutrophils, formation of pus and abscesses within the interstitial tissue and tubules>tubular necrosisfever, chills, flank pain, dysuria, CV tenderness, leuko casts, bacterial casts, WBC positive-chronic: predominent interstitial inflammation, progressive interstitial firbrosis and diffuse scarring>tubular atrophy>deformation and sclerosis of the renal calicoes and pelvisrecurrent infection, defects in tubular funciton, renal failure
Arterionephrosclerosis
HTN produces hyaline thickening of the arterial and arteriole walls-decrease renal blood flow, ischemia-ongoing>structural thickening and remodeling and decreased renal blood flow-HTN produces microvascular injury, inflammatory response, plasma proteins enter vessel walls, ischemia of glom and post glom structures>stimulates Renin, vasoconstriction, reduces GFR,
Diabetic nephropathy
impairment in the auto regulation of the glomerular microcirculation form DM-glom HTN and hyperfusion>injury-GBM theckening, mesangial expansion and sclerosis from increase in mesangial matrix/proliferation of cells, activation of fibroblasts and mesangial sclerosis>loss of charge GBM, tubular interstitial injury and fibrosis*microalbinuria, proteinuria, renal insufficiency and RF
Postrenal Disease Patho
-dilation of renal pelvis and calyces-compression of vasculature -back up in tubule>initially filtrate diffuses into interstitial and circulatory system but eventually will alter tubular function, impair ability to concentrate urine and diminish GFR-reduced froward tubular flow stimulates renin production and causes HTN-obstruction triggers inflam process>interstitial fibrosis>atrophy
types of kidney stones
-struvite: Mg and ammonium phosphate, very large, occur in alkaline urine due to UTI-cystine stones: inherited d/o affecting reabsorption of certain amino acid produces cystine stones
Azotemia
-increased BUN, Cr and other nitrogenous wastes in the blood-hallmark sign of ARF
ARF
phase 1: initiating eventphase 2: maintenance; azotemia, sustained decrease in UO>oliguria (less than 1 ml/kg/h infants and less than 400 ml/day in adults), anuriaphase 3: recovery: last for months, polyuria, gradual dissipation of azotemia, gradual improvement in ability to filter/conserve ions and fluids
CRF stages
-loss of nephrons increase functional burden of remainders; HTN of nephron; hyper filtration-subsequent fibrosis, scarring and increased rate of nephron destruction and lossstage 1: GFR is 50% normalstage 2: GFR is 20% to50% normalstage 3: GFR less than 20% normalstage 4: GFR is less than 5% normal
CRF manifestations
Cannot secrete enough H or generate enough buffers>kussmaul respirations to “blow off” CO2 and compensate for =ACIDOSIS-impaired water and Na balance, increased blood volume>pulmonary and peripheral edema-stimulation of renin-angiotensin-aldosterone> more HTN and edema -increased K plasma because decreased secretion in tubule-decreased Vitamin D activation because remaining cannot activate enough V D and less calcium absorption and breaks down from bone to get calcium-hyperhosphatemia from calcium reabsorption form bone-GI n/v, PUD=suppresses bone (platelet, leukocytes), wastes build up and affect all systems (K affects heart)
Exocrine pancreas
1 Acini-80%-85%-surround lumen, contain intracellular zymogen granules which contain digestive enzymes-pancreatic duct cells2 pancreatic islets 15-2%