overview of renal physiology Flashcards
Hypovolemia
A deficit in intravascular volume
Signs of hypovolemia
- signs of low effective circulating volume
- it activates all mechanism that go along with low ECF including renin, angiotensin
Dehydration
- state of intracellular volume loss
- can only be seen in setting of hypernatremia (this is what pulls volume out of the cells)
Things your kidneys do for you
- Clean blood of toxins
- Balance electrolytes
- Balance water intake/losses
- Produce or modify hormones
- Vitamin D
- Erythropoietin - Calcium/phosphate/PTH
- bone health - Acid base balance
- Manage blood pressure
- Growth
- Psychosocial/developmental
Areas of the nephron
- Renal corpuscle
- Proximal convoluted tubule
- Loop of Henle
- Distal convoluted tubule
- Collecting duct
- Papillary duct
Renal corpuscle function
Production of filtrate
composed of bowmans capsule + glomerulus?
Proximal convoluted tubule function
Reabsorption of water, ions, and all organic nutrients
Loop of henle function
Further reabsorption of water (descending limb) and both sodium and chloride ions (ascending limb)
Distal convoluted tubule function
Secretion of ions, acids, drugs, toxins
Variable reabsorption of water, sodium ions and calcium ions (under hormonal control)
Collecting duct function
Variable reabsorption of water and reabsorption or secretion of sodium, potassium, hydrogen, and bicarbonate ions
Papilary duct function
Delivery of urine to minor calyx
4 compartments of the kidney
1) Vascular
2) Interstitial
3) Glomerular
4) Tubular
How any liters does kidney filter per day in adult male
Approx 180 L per day in adult male
Global assessment of renal clearance
-usually measured by glomerular filtration rate
Average glomerular filtration rate
90-120 ml/min
How does kidney balance electrolytes
- via transporter systems throughout tubule (both energy requiring and passive)
- can absorb and secrete various substances to maintain homeostasis
Effect of damage to one segment of tubule
-may lead to compensatory function of another segment
Prime directive for Kidney
Preserve vascular function –> via salt preservation (99% + of salt in reabsorbed)
How much urine is produced per day
0.5- 10 L per day
Factors that control water balance
- osmotic load
- renin/angiotensin
- antidiuretic hormone
- renal blood flow
- renal concentration gradient
How kidney produces/modifies hormones
1) activates vitamin D by 1-alpha-hydroxylation of 25-vit D from the liver to make 1, 25-Vit D
2) Produces erythropoietin from interstitial cells which assists in production of RBCs
How kidneys contribute to bone health (3)
1) production of 1, 25 Vit D
2) control of Calcium and phosphate reabsorption/loss
3) respond to variety of external stimuli such as PTH or Acidosis in ways that can affect bone
How kidneys contribute to acid/base handling
1) Reclaim HCO3 that is filtered (proximal tubule)
2) Regenerate the lost buffering capacity to allow on-going acid production (distal tubule)
What complex interactions are involved in blood pressure
1) Salt and water balance
2) Sympathetic nervous system
3) Hormonal effects
- angiotensin, renin, aldosterone
How kidney is involved in growth (3)
- chronic acidosis
- inability to clear IGF-BPs
- bony abnormalities
How kidney is involved in Psychosocial /development
- uremia clouds the min
- significant developmental delay in infants not dialyzed well enough
- math and abstraction reasoning affected disproportionately
- effects on QoL, anger, management, forgetfullness
