DI sole 3

Question 1

Effect of ingesting NaCL on ADH and thirst

Answer 1

• Brain osmoreceptors SHRINK and person feels THIRSTY and drinks water
• Brain INCREASE release ADH so more water is re-absorbed (conc urine)
• increased water ingestion and conctrate urine result in EXPANSION of ECF and rise in blood pressure
• increased blood pressure causes DECREASE in ADH secretion
• result PRESSURE DIURESIS (and natriuresis) which causes return to normal ECF volume

Question 2

Effect of ingesting NaCl on Atrial natriuretic peptide

Answer 2

• Ingesting NaCl expands plasma volume
• PLASMA VOLUME EXPANSION stretches the atria which increases secretion of the natriuretic peptides

Question 3

REnal response to volume contraction

Answer 3

• Renin-angiotensin-aldosterone system is ACTIVATED
• ADH from the posterior pituitary gland is stimulated
  
  • increases in Na+ and H20 REABSORPTION
• sympathetic nerves are stimulated
  
  • Decrease glomular filtration rate
  • increase Na+ resopriton in proximal tubule
  • increase renin –> increase angiotensin II
    
    • increase Na+ resorption of proximal tubule
    • activates aldosterone –> increase Na+ and water resorption in collecting ducts

Question 4

Renal response to Volume EXPANSION

Answer 4

• Decreases sypathetic activity (sodium and fluid retaining mechs)
  
  • increase glomerular filtration rate
  • decrease reinin
  • decrease Na+ resorption in proximal tubule
• Increased stretch on the cardiac right atrium releases atraiil natriuretic peptide
  
  • decrease ADH
  • decrease Na+ and water resorption

INCREASE Na+ and WATER EXCRETION!!!!

Question 5

Distribution of ECF between the Interstitial space and vascular system

Answer 5

• Ingested fluid initially goes into the blood, but rapidly becomes distributed between the interstitial spaces and plasma
• blood volume and ECF usually are controlled simultaneously
• there are circumstances, however, in which distribution of ECF between interstitial spaces and blood can vary greatly
• PRINCIPLE FACTORS that cause accumualtion of fluid in interstiital spaces include
  
  • INCREASED CAPILLARY HYDROSTATIC PRESSURE
  • DECREASED PLASMA COLLOID OSMOTIC PRESSURE
  • INCREASED PERMEABILITY OF CAPPILLARIES

Question 6

Renal clearance

Answer 6

• Renal clearance of a substance is the VOLUME OF PLASMA that is COMPLETELY CLEARED OF THE STUBSTANCE by the kidney PER UNIT OF TIME
• It is a theoretical concept since there is no signle volume of plasma that is completely cleared of a substance
• USED TO QUANTIFY THE RATE at which blood flow through the kidneys as well as basic function of the kidneys.

Question 7

Renal clearance calculation

Answer 7

• Cx = clearance of substance X
• Px = plasma conc of X
• V = urine flow rate
• Ux = urine conc of X

GFR = Cx if the substance is freely filtered and not re-absorbed or secreted by the renal tubules

• ex: inulin, creatinine

Question 8

Acute kidney injury (acute renal failure)

Answer 8

• Syndrmoe that results in a sudden DECREASE in kidney function or damage from few hours to few days
• DEFINED as a RAPID DECLINE in GLOMERULAR FILTRATION RATE accompanied by accumulation of waste products in the blood and inability to keep the body balance of luid and electrolytes

Question 9

Causes of acute kidney injury (AKI)

Answer 9

• Pre-renal (result from kidney hypoperfusion)
  
  • intravascular volume depletion (hemorrhage, diarrhea, vomiting)
  • cardaic failure (MI)
  • Peripheral vasodilation (hypotension, shock)
  • renal hemodynamic abnormalities (thrombosis of renal artery)
• Renal (intrinsic, intra-renal)
  
  • vessela nd glomerular injury, tubular epithelial injuyr
  • renal interstitial injury
• Post-renal (urinary tract obstruction
  
  • kidney stones, uretic obstruction, bladder/urethral obstruction

Question 10

Physiological effect of AKI

Answer 10

• Water and sodium overload (edema and hypertension)
• increase in plasma potassium conc (hyperkalemia)
• metabolic acidosis
• anuria (severe AKI)

Question 11

Chronic kidney disease (chronic renal failure)

Answer 11

• It results in progressive and irreversbile loss of large number of functioning nephrons
  
  • symptoms don’t occur until funtion nephrons fall to at least 70-75% below normal
• due to disorders of blood vessels, glomeruli, tubules, renal interstitium, and lower urinary tract
  
  • diabetes, obesity, hypertension, lupus, glomerulonephritis, infection, congenital disorders

Question 12

Glomerulonephritis

Answer 12

• Can be acute or chornic
  
  • acute –> acute kidney injury
  • Chronic –> chronic kidney disease and nephrotic syndrome
• Patients develop hematuria, proteinuria, azotemia, renal sodiuma nd water retention

Question 13

Nephrotic syndrome

Answer 13

• INCREASED GLOMEMRULAR PERMEABILITY to large proteins such as albumin
  
  • GFR is decreased
  • SODIUM AND WATER RETENTION
  • Edema and decrease in plasma volume

Question 14

Describe relationship of HTN with kidney disease

Answer 14

• HTN can exacerbate injury to the kidney and abnormalities of kidney function can cause HTN
• renal lesions that REDUCE THE ABILITY OF KIDNEY TO EXCRETE sodium and water promote HTN
  
  • increased renal vascular resistance
  • decreased glomerular capillary filtration fraction coefficient
  • excessive tubular sodium re-absorption