Renal, Topnotch + CDB Flashcards
Length of the ureter
25-35 cm
Origin of the nephron
Metanephric blastema
Origin of the collecting duct system
Ureteric bud
pH compatible with life
6.8-8.0
Stimulus for EPO production by interstitial cells of kidney
Hypoxia
Form of vitamin D produced in kidneys
1,25-hydroxycholecalciferol
Enzyme in the kidney that converts vitamin D to its active form
1a-hydroxylase
Function of kidney during starvation
Gluconeogenesis
Vertebral level of kidneys
T12-L3
Weight of 1 kidney
150g
Part of kidney that is pain sensitive
Capsule
Organism implicated in staghorn calculi/mg ammonium po4/struvite
Proteus mirabilis
Renal circulation
Renal artery > segmental artery > interlobar artery > arcuate artery > interlobular artery (cortical/radial) > afferent arteriole > glomerular capillaries > efferent arteriole > peritubular capillaries/vasa recta > interlobular vein > arcuate vein > interlobar vein > segmental vein > renal vein
Cxs of glomerular capillaries (2)
1) Highly fenestrated hence responsible for GFR
2) Only capillaries that leas to arterioles and not venules
Hairpin loop-shaped peritubular capillaries of the juxtamedullary nephrons
Vasa recta
Creates corticopapillary osmotic gradient
Countercurrent multipliers
Structure known as the countercurrent multiplier
Loop of Henle
Maintains the corticopapillary osmotic gradient
Countercurrent exchangers
Structure known as the countercurrent exchanger
Vasa recta
Substances moved in circles by the countercurrent exchanger (2)
1) Na
2) Urea
Urge to urinate
150 mL
Reflex contraction
300mL
Sense of fullness
400mL
of nephrons per kidney
1M
The kidneys undergo compensatory regeneration upon __% damage to nephrons
75%
Cortical vs Juxtamedullary nephrons: Percentage
75%, 25%
Cortical vs Juxtamedullary nephrons: Loops of Henle
Short-long
Cortical vs Juxtamedullary nephrons: Capillary network
Peritubular capillaries-vasa recta
Diameter of pores of capillary endothelium
8nm or 80A
Vasoactive substances secreted by capillary endothelium
1) NO
2) ET-1
Form the visceral epithelium in the glomerulus
Podocytes
Where filtrations slits are located in kidneys
Podocytes
Function of mesangial cells
1) Contractile elements
2) Mediate filtration
3) Take up immune complexes
Components of JG apparatus
1) JG cells
2) Macula densa
3) Lacis cells
Glomerular cells of the afferent arterioles
JG cells
What JG cells secrete
Renin
Where macula densa is located
Wall of DCT
Function of the macula densa
Monitor Na concentration in the DCT
Site of kidneys most susceptible to ischemia
PCT
% sodium, K, and H2O reabsorbed in the PCT
66%
% glucose and aa reabsorbed in PCT
100%
Part of loop of Henle permeable to water but not to solutes
Descending limb
Part of loop of Henle permeable to solute but not to water
Ascending limb
Substances that kidneys filter only (2)
1) Inulin
2) Creatinine
Substances that kidneys filter and secrete (2)
1) PAH
2) Organic acids and bases
GFR is __% lower in females
20-25%
Fraction of renal plasma flow that is filtered
Filtration fraction
Normal filtration fraction
20%
Formulas for filtration fraction
GFR/RPF
Substance used to determine RPF (gold std)
PAH
Size of substance freely filtered in kidneys
20A or less
Size of substance not filtered at all in kidneys
> 42
Filterability of 1.0
Freely filtered as water
Filterability of 0.75
Filtered only 75% as rapidly as water
Filterability according to charge
Positive > neutral > negative
Portion of renal corpuscle affected by NSAID and mechanism
Afferent arteriole; inhibition of PG (dilates afferent arteriole)
Portion of renal corpuscle affected by ACEI and mechanism
Efferent arteriole; inhibition of ATII (constricts efferent arteriole)
Glomerular hydrostatic pressure
60 mmHg
Net filtration pressure (GFR)
10 mmHg
Effect on GFR when efferent arteriole is moderately constricted
Increase
Effect on GFR when efferent arteriole is severely constricted
Decrease
Effect on GFR when ultrafiltration coefficient (Kf) is increased
Increase
Causes of decreased Kf
1) DM
2) Htn
3) Renal diseases
Cause of increased hydrostatic pressure in the bowman’s space
Urinary tract obstruction
Glomerular filtration forms
Primitive urine
% CO received by kidneys
25%
Organs that are sensitive to ischemia
1) Brain
2) Liver
3) Kidney
Type of infarct in the kidney
Wedge-shaped white or anemic infarct
Renal cortex vs medulla: greater renal blood flow
Renal cortex
BP at which renal autoregulation is optimal
80-170 mmHg
Massive sympathetic stimulation that results in massive vasoconstriction of kidneys
CNS ischemic response
Substances secreted as autoregulatory mechanisms to maintain GFR
1) Adenosine
2) NO
3) ATII
Effect of adenosine on kidneys
Afferent arteriole vasoconstriction
Effect of nitric oxide on kidneys
Afferent arteriole vasodilation
Percentage of solute reabsorbed is held constant
Glomerulotubular balance
Concentration at which substance starts to appear in the urine
Renal threshold
Concentration at which all excess substance appear in the urine or the limit to the rate at which solute can be transported (reabsorbed)
Renal transport maximum
Renal Tmax of glucose
375 mg/dL
Renal threshold of glucose
200 mg/dL
Filtered load at renal threshold of glucose
250 mg/min
Normal filtered load of glucose
125 mg/min
Kidney transport mechanism that does not exhibit Tmax and threshold
Gradient-time transport
Factors that affect transport of substances that use the gradient-time mechanism (3)
1) Electrochemical gradient
2) Membrane permeability
3) Time
Relationship between flow rate and rate of transport in gradient-time transport
Inverse
Epithelium of PCT
Low columnar with extensive brush border
Osmolarity of PCT
Isosmotic
Epithelium of thin segments of loop of Henle
Simple squamous
Epithelium of thick segments of loop of Henle
Simple cuboidal
% of filtered water reabsorbed in loop of Henle
20%
% of filtered Na,K,Cl reabsorbed in loop of Henle
25%
Ion channel inhibited by loop diuretics (Furosemide, Bumetanide, Ethacrynic acid)
Na-K-2Cl
Epithelial lining of distal tubule
Simple cuboidal
Aka Goormatigh or Polkissen cells or agranular cells
Lacis cells
Cells found in second part of distal tubule
1) Principal cells
2) Intercalated cells
Function of principal cells (3)
1) Reabsorb Na
2) Secrete K
3) Reabsorb H2O
Function of intercalated cells (2)
1) Reabsorb K
2) Secrete Na
3) HCO3 regulation
Transport systems by which intercalated cells secrete H+ (2)
1) Na-H countertransport
2) H-ATPase
Part of kidney responsive to aldosterone
DT
Part of kidney responsive to vasopressin
DT and CD
% filtered water reabsorbed in DT
5
Part of renal tubules impermeable to urea
DT
Part of renal tubules permeable to urea
CD
Site for regulation of final urine volume and concentration
CD
Effect of aldosterone on kidneys (3)
1) Na reabsorption
2) Water reabsorption
3) K secretion
Effect of ATII on kidneys (2)
1) Na reabsorption
2) Water reabsorption
Effect of ANP and BNP on kidneys
Decrease Na reabsorption
Effect of PTH on kidneys
1) Increase Ca reabsorption
2) Decrease PO4 reabsorption
3) Increase 1a-hydroxylase
Triggers for ADH secretion and respective sensors
1) Increased osmolarity (Hypothalamus)
2) Decreased BP (atrial stretch receptors)
3) Decreased blood volume (carotid sinus and aortic arch)
Effect of alcohol on body fluid regulation of kidneys
Decreases ADH secretion
Hormone secreted by DT and CD that acts similar to ANP
Urodilatin
Change in osm that triggers ADH secretion
1%
Change in blood volume that triggers ADH secretion
10%
Stimulus for renin secretion by JG cells
Decrease in BP
Effect of renin
Angiotensinogen > angiotensin I in liver
Where and angiotensin I is converted to angiotensin II and enzyme responsible
Lungs and kidneys via ACE
CKD with normal size
1) SLE
2) HIV
3) PTB
4) Amyloidosis
5) Sarcoidosis
All tubular capillaries are derived from
Efferent arterioles
Onion-skinning or fibrinoid necrosis is seen in what renal disease
Malignant nephrosclerosis
Most common site of abdominal aneurysm
Infrarenal/before bifurcation of abdominal aorta
Symptom of abdominal aneurysm
Abdominal bruit
Most common type of htn
Essential/idiopathic
Most common cause of secondary htn
Renovascular dse
Most common renovascular disease
Renal artery stenosis
Filtration rate - reabsorption rate + secretion rate
Excretion rate
How many times is plasma volume filtered in a day
60x
% water reabsorbed from filtered volume
99%
% phenol reabsorbed from filtered volume
0%
Regulation of urine concentration (2)
1) Medullary countercurrent system
2) Vasopressin
High permeability of thin descending limb to water is via
Aquaporin-1
Nodular sclerosis of glomerular membrane is seen in what disease
DM
Microscopic finding in kidneys with DM
Kimmelsteil-Wilson Lesions
Microscopic finding in kidneys with minimal change disease
Effacement of podocytes
Combined blood flow through both kidneys in an average adult
1100mL/min
Renal vessels with greatest resistance (4)
1) Interlobar artery
2) Interlobular artery
3) Afferent arteriole
4) Efferent arteriole
Formula for renal blood flow
(R artery pressure-R vein pressure)/Total renal vascular resistance
Drug that causes diabetes insipidus by interfering with ADH receptors on DT
Lithium
Major ion secreted into tubules coupled with sodium entry
Hydrogen
Forces that propel the urine along the ureter
1) Gravity
2) Peristaltic contractions
Treatment for post-operative bladder atony
Bethanechol
Where EPO is produced
Interstitial peritubular cells
Usual daily urine output
700-1400mL
Why ACEI exacerbates cough
ACE inhibits bradykinin
Normal venous pH
7.35
Normal interstitial fluid pH
7.35
Body fluid buffer systems (3)
1) Bicarbonate
2) Phosphate
3) Intracellular proteins
The respiratory buffer responds to
H+ levels
Respiratory regulation of acid-base balance is __% effective in returning pH back to normal
50-75%
Respiratory regulation returns pH back to normal within ___ minutes
3-12
Mechanisms of renal regulation of acid-base balance (3)
1) Excess H+ secretion
2) HCO3 reabsorption
3) Production of new HCO3 using ammonia and phosphate buffers
Normal HCO3
22-26 mmol/L
Normal pCO2
35-45 mmHg
Acid-base imbalance due to conditions resulting in decreased ventilation
Respiratory acidosis
Acid-base imbalance due to conditions resulting in increased ventilation
Respiratory alkalosis
Respi acid vs alka: Airway obstruction
Respi acid
Respi acid vs alka: Pneumonia
Respi alka
Respi acid vs alka: ARDS
Respi acid
Respi acid vs alka: Pulmonary embolus
Respi alka
Respi acid vs alka: COPD
Respi acid
Respi acid vs alka: High altitude
Respi alka
Respi acid vs alka: Psychogenic
Respi alka
Respi acid vs alka: Salicylate intoxication
Respi alka
Formula for plasma anion gap
Na - (HCO3 + Cl-)
Met acidosis where there is excess organic anions to maintain electroneutrality
HAGMA
Met acidosis where there is increased chloride to maintain electroneutrality
NAGMA
HAGMA (11)
MUDPILES
Methanol, uremia, DKA, paraldehyde, propylene glycol, iron, isoniazid, idiopathic acidosis, lactic acidosis, ethylene glycol, ethanol, salicylic acid
NAGMA (6)
HARD UP
Hyperalimentation, acetazolamide, RTA, diarrhea, ureteroenteric fistula, pancreaticoduodenal fistula
Conditions resulting in metabolic alkalosis (5)
1) Loop diuretics
2) Thiazide diuretics
3) Vomiting
4) Hyperaldosteronism
5) Ingestion of alkaline drugs
Osmolarity of medullary interstitium
1200-1400
Segment of tubules that is virtually impermeable to water
TALH
Most important cause of high medullary osmolarity
TALH
