PSL201Y1 Lecture Notes - Mutation, Reabsorption, Exocytosis
Document Summary
To maintain homeostasis, what comes into the body and what is produced must equal the sum of what. The concept of balance is used by the body and what is eliminated: The volume of plasma is determined almost entirely by its water content because solutes make only a negligible direct contribution to the volume. The amount of solute in plasma indirectly affects plasma volume because changes in plasma osmolarity can cause water to shift between the plasma and other body fluid compartments. The transport of materials across the wall of the gastrointestinal tract normally amounts to a net gain of solutes and water by the body. The transport of materials across the walls of the renal tubules amounts to a net loss of water and solutes by the body. Changes in volume and/or composition occur when materials enter the plasma faster than they exit, or vice versa.
