BIOL 2P93 Lecture Notes - Juxtaglomerular Apparatus, Hematocrit, Baroreceptor

• School: Brock University
• Department: Biological Sciences
• Course: BIOL 2P93
• Professor: Jenny Janke

Document Summary

Control of blood plasma volume: typical 70kg person has 5l blood (3l plasma, 2l hematocrit, glomerulotubular balance a change in gfr (flow) => a proportional change in. Na reabsorption so that the fraction reabsorbed is constant: blood volume is normally constant over a wide range, na intake => ecf volume, na intake => mean arterial blood pressure (but blood volume = const) iv. [na] is main determinant of ecf volume & [k] of icf volume: volume/pressure sensors, extra-renal sensors, arterial baroreceptors. 2. intrathoracic low pressure receptors: renal sensors juxtaglomerular apparatus. 3: adh release renal tubules (sense altered hemodynamics) Ii: very sensitive to small changes in osmolality, not sensitive to changes in blood volume until ~10% decrease, then has steep response. Rocking the boat : addition of dry nacl to ecf osmolarity => h2o shift to ecf (icf, addition of h2o to ecf both icf & ecf expand but with maintained ratio & contraction)