Hormonal control, Fluid and electrolyte balance, Kidney disease Flashcards
What is the primary route for excreting ions and water?
The kidney
WHat other routes does the body use to excrete water and ions?
Feces
Sweat
Lungs (via CO2 and bicarbonate)
Which systems respond rapidly to fluid/electrolyte imbalance?
Respiratory and cardiovascular systems (uncer neural control)
Which organ responds slowls to fluid imbalance and is under hormonal control?
The kidneys
What are the suorces of water intake?
Ingestion
Metabolism
IV injection
What are the methods of water loss?
Urine
Feces
Insensible loss (skin/lungs)
Pathological causes (vomiting, diarrhea, sweating)
What does vasopressin do?
Increase water reabsorption in the nephron’s collecting duct
What stimulates vasopressin release?
Increased blood osmolarity and low blood volume
What is the mechanism of vasopressin action?
Stimulates aquaporin insertion into apical membrane
What is the half-life of vasopressin?
About 20 minutes
What inhibts vasopressin release?
Alcohol
How does vasopressin secretion vary with time?
Circadian pattern - less urine at night
What happens when NaCl levels rise?
Osmolarity increases –> vasopressin released –> water retained –> thirst stimulated
What does aldosterone do?
Increases Na+ reabsorption and K+ secretion in the distal nephron
What stimulates aldosterone release?
Low blood pressure
What triggers renin secretion?
Decrease in blood pressure
What is the of RAAS activation?
Renin –> angiotensinogen –> ANG I –> (via ACE) –> ANG II
What are the effects of ANG II?
Vasopressin release
Increased thirst
Vasoconstriction
Stimulation of CVCC
Na+ reabsorption in the proximal tubule
What is natriuresis?
Urinary sodium loss
What produces artial natriuretic peptide (ANP)?
Artial myocardial cells
What produces brain natiuretic peptide (BNP) ?
Ventricular myocardial cells and some brain neurons
What are the effects of ANP/BNP?
Increase GFR
Reduce Na+ reabsorption
Supress RAAS
Reduce blood volume
What is normal plasma pH?
7.38 - 7.42
What happens if pH deviates too much?
Protien denaturation and metbaolic dysfunction
What are the body’s buffer systems?
Protiens
Pohsohate ions
Bicarbonate (HCO3)
How aare most acid-base imbalances corrected?
Ventilation (75%)
How do kidneys help with pH balance?
Use ammonia and phosphate buffers to ecrete H+
What does high specific gravity indicate?
Dehydration or diabetes
What can cause acidic or alkaline urine pH?
Diet
Disease
Kidney stone type
What does urine glucose suggest?
Diabetes mellitus
What does high bilirubin in urine indicate?
Liver disease or failure
What does ketones in urine suggest?
Diabetes or low-carb diet
What do plasma proteins in urine indicate?
Kidney damage
What do nitrites/nitrates suggest?
UTI
What does blood in urine suggest?
Infection or kidney damage
What do white blood cells in urine suggest?
UTI
What cause diabetes insipidus?
Poor secretion (cranial DI)
Response (nephrogenic DI) to vasopressin
What is the result of DI?
Polyuria (5-10L/day)
Dilute urine
Intense thirst
Who is at risk for diabetic nephropathy?
30-40% of type 1 diabetics
10-20% of type 2 diabetics
What are key features of diabetic nephropathy?
Early increase in GFR, followed by proteniria and decrease in GFR due to mesangial cell growth
Why are women more prone to UTI’s?
Shorter urethre
Clsoer to anus
What serious kidney infection can UTI’s lead to?
Pyelonephritis
What is glmoerulonephritis?
Inflammation of glomeruli
What leaks into urine with glomerular damage?
Blood proteins (albumin) and cells
Difference between primary and secondary glomerulonephritis?
Primary: Direct kidney disease
Secondary: Due to another condition (e.g., lupus)
What causes kidney stone pain?
Stones blocking the ureter
What are stones made of?
Crystals of inorganic ions (e.g., calcium)
What risk factor increases kidney stone information?
Hypercalciuria and high vitamin D intake
What causes polycystuc kidney disease?
Autosomal dominant mutation (chromosome 16)
What are symptoms of PKD?
Hypertension
Proteinuria
Haematuria
What is the treatment for PKD?
Dialysis or transplant
What happens in chronic renal failure?
Progressive nephron destruction –> decrease in GFR, oliguria/anuria
What causes chronic renal failure?
Hypertension
Diabetes
Aging
Altherosclerosis
WHat hormone is affected in chronic kideny disease?
Erythropoietin (anemia)
What are signs of end-stage renal failure?
Uraemia, acidosis, hyperkalaemmia –> confusion, coma, death
What are the treatments for end stage renal failure?
Hempdoalysis or kidney transplant
What are the two main types of dialysis?
Hemodialysis
Peritoneal dialysis
What is RRT?
Renal Replacement Therapy - dialysis or transplant
