Physiology Flashcards
how can plasma volume be measured
radiolabeling albumin
how can extracellular volume be measured
by inulin or mannitol
what type of collagen is present in the basement membrane
type IV collagen
what barriers exist in the glomerular filtration barrier for preventing molecules to enter the glomerulus
charged barrier - GFB contains negatively charged ions which prevent negatively charged ions from crossing through i.e. albumin
size barrier - fenestrated capillary endothelium and podocytes prevent entry of certain sizes of molecules
how can GFR be calculated
inulin clearance as it is neither absorbed nor secreted
GFR = (urine inulin X urine flow rate) / plasma inulin
does Creatinine clearance under or overestimate GFR
slightly overestimates because a small amount of creatinine is secreted from the proximal renal tubules
how can effective renal plasma flow be estimated
using para-amniohippuric acid (PAH) clearance
how to work out filtration fraction
FF = GFR/RPF
what effect does prostaglandins have on the arterioles in the kidney
prostaglandins Dilate Afferent arterioles
PDA
what effect does ACE II have on the arterioles of the kidney
Angiotensin ii Constricts Efferent arterioles
ACE
what effect does afferent arteriole constriction have on GFR and RPF ?
GFR decreases
RPF decreases
what effect does efferent arteriole constriction have on GFR and RPF ?
GFR increases
PRF decreases
what effect does and increase or decrease of protein concentration have on GFR and RPF ?
increased protein - decreases GFR, no change in RPF
decreased protein - increases GFR, no change in RPF
what effect does constriction of ureters have on GFR and RPF ?
decrease GFR
no effect on RPF
where is glucose reabsorbed n the kidney and through which transporter
proximal convoluted tubules by Na/glucose co-transport (GLUT)
why can pregnancy cause glucosuria at normal plasma glucose levels
increased GFR and filtration of all substances inlcuidng glucose. the glucose threshold occurs at lower levels which results in urinary excretion of glucose even at normal blood levels
what part of the kidney does fanconi’s syndrome affect
proximal convoluted tubule
renal tubular defect syndromes and location of which they act on
Fanconi’s bagles
fanconi- PCT
Bartters syndrome - thick ascending loop of henle
Gitelman syndrome - DCT
little syndrome - collecting tubules
SAME - collecting tubules
features of fanconi syndrome
reabsorption defect on the proximal convoluted tubule
increased excretion of glucose, HC03, PO4, and amino acids
results in renal tubular acidosis -> metabolic acidosis, low phosphate and low K
causes of fanconi syndrome
Fanconi Has Multiple Interesting Drinks
hereditary i.e. wilsons
ischaemia
multiple myeloma
drugs i.e. cisplatin, lead poisoning
features of primary hyperaldosteronism but with low aldosterone levels
Liddle syndrome or Syndrome of apparent minealocorticoid excess
where is renin produced from?
juxtaglomerular cells
where is ACE produced from
lungs and kidneys
where are ANP and BNP produced from
ANP - atria
BNP - ventricles
where is erythropoetin produced from
interstitial cells in peritubular capillary bed
what effect does low and high doses of dopamine have on the kidney
low doses - dilates interlobular arteries, afferent arterioles and efferent arterioles to increase renal blood flow
high doses - vasoconstricts
defect in renal tubular acidosis type 1
distal RTA = type 1
inability of alpha intercalated cells in DCT to secrete h which results in no new HCO3 being generated = metabolic acidosis
defect in renal tubular acidosis type 2
proximal RTA = type II
defect in proximal convoluted tubule reabsorption of HCO3 = increased secretion = metabolic acidosis
urinary PH of RTA type 1 and 2
type 1 urinary PH > 5.5
type 2 urinary PH < 5.5 but can be > 5.5 when filtered HCO3 exceeds resorptive threshold
how does CKD affect calcium and phosphate
unable to excrete phosphate = hyperphosphataemia
this in turn causes low calcium which stimulates parathyroid gland = hyperparathyroidism
= osteodystrophy
effects of IV 5% dextrose
the dextrose is quickly metabolised so is essentially like drinking water.
pure water causes serum osmolaliy to reduce which reduces ADH release. Reduced ADH would cause less aquaporin channels to be inserted into the collecting duct = dilute urine as less water is being reabsorbed. It would also reduce urea absorption as ADH causes reabsorption of urea to maintain interstitial conc gradient
primary site of absorption of the following electrolytes;
Na, K, Cl, glucose, Ca, Mg, PH04
Na, Cl, glucose, K –> proximal convoluted tubule
Mg –> thick ascending loop of henle
how is magnesium levels maintained
not regulated by hormones unlike other electrolytes. Mainly regulated by absorption in the thick ascening loop of henle.
Tight junctions due to caludin 16 and 19 allow for the paracellular movement of Mg required for reabsorption
what part of the kidney is impermeable to water
ascending loop of henle
what part of the kidney becomes permeable to water in the presence of ADH
collecting duct
what part of the kidney is responsible for tubuloglomerular feedback
macula densa
located in distal convoluted tubule
what is the main electrolyte absorbed in thick asencing loop of henle
magnesium
eosinophillic nodular glomerulosclerosis
kimmesteil wilson lesions = diabetic nephropathy
glomerulonephritis associated with HIV
focal segmental glomerulosclerosis
spike and dome appearance of flouroscopy
membranous glomerulonephritis
glomerulonephritis that can be associated with solid tumours
membranous
what type of hypersensitivity reactionis post strep glomerulonephritis
type III
glomerulonephritis associated with HBV/HCV
membranoproliferative
glomerulonephritis associated with SLE
diffuse proliferative
lumpy bumpy of flouroscopy
post strep glomerulonephritis
splitting and tram stracks on H&S and PAS stains
membranoproliferative glomerulonephritis
glomerular subendothelial immune deposits
diffuse proliferative
glomerular mesangial immune complex deposits
membranoproliferative
