2 Renal Physiology refresher and Mendelian forms of HTN Flashcards
Effects of adding fluids
Hypotonic NaCl - Increases intracellular fluid more than extracellular
Isotonic NaCl- Increases extracellular fluid only
Hypertonic NaCl- increases extracellular shrinks intracellular compartmments
Fluid distribution
2/3 intracellular.
280-300 mOsm/l
Net filtration pressure
usually 10mmHg = 60(glomerular hydrostatic) - 18(bowmans capsule pressure) - 32 (glomerular oncotic pressure)
Normal GFR
125 ml
GFR
GFR= ultrafiltration coefficient (net filtration force)
Relationship between GFR and MAP
No change in GFR with higher BP because of autoregulation.
- myogenic
- tubuloglomerular feedback
Hormones that decrease GFR
NE, Epinephrine, Endothelin (all by increasing constriction)
Hormone with no change in GFR/ prevention of decreasing GFR
ANGII (preferentially constricts efferent arteriole)
Hormones/substances that increase GFR
Endothelal derived NO
Prostaglandins
Filtration barrier
Fenestrations = 700 angstroms
Basement membrane= IV collagen, laminin, fibronectin (neg proteins)
Podocyte slit pores = 40-140 angstroms
Solubility of proteins
Myoglobin (17kDa) .75
Albumin (69 kDa) .005
Thin descending loop function
passive resorption of water 2/2 cortical medullary osmotic gradient
Thin ascending limb function
Passive resorption of sodium and excretion of urea to dilute tubular fluid
Thick ascending limb
- 25%sodium resorbed by NA/K/CL transporter
- Na resorbed in exchange for H+
- Sodium potassium ATP pump on interstitial side
- Chloride pore on interstitial side
- positive luminal fluid also pushes K, Na, MG, and Ca into interstitium via paracellular diffusion
Furoseminde
Blocks NA, K, CL cotransporter