Body Fluid Movement among Compartments (Nursing)

00:01 So we look at how fluids move between the intracellular and extracellular compartments.

00:08 by looking at the different forces that act on these fluids.

00:12 Osmotic and hydrostatic pressures are going to regulate the continuous exchange and mixing of fluids between compartments.

00:23 Water is going to move freely along its osmotic gradient.

00:29 All of our bodies fluid osmolality is almost equal at about 300 milliosmoles.

00:37 Any change in the solute concentration of any compartment is going to lead to a net water flow.

00:45 Remember, water follows salt.

00:48 So if the extracellular fluid osmolality goes up or becomes more salty, water we'll leave ourselves and follow the salt out of the cells into the extracellular fluid.

01:03 Conversely, if the osmolality of the extracellular fluid goes down, then that means that the solute inside of the cells is higher than that outside of the cells and water will then enter our cells.

01:19 So, if we look at movement among compartments, we find that our plasma is going to move in and out of our interstitial fluid.

01:30 This is exchange occurs across our capillary walls.

01:35 Fluid is going to leak from the arteriolar end of our blood capillaries, and be reabsorbed at the venule end of the blood capillaries.

01:46 Any fluid that is not picked up or reabsorbed by the venule is then picked up by the lymphatic vessels.

01:54 They will eventually return this fluid to the blood after filtering it.

02:01 Fluids that move from the interstitial fluid to the intracellular fluid are going to move back and forth across the cell membrane.

02:10 The cell membrane involves two way osmotic flow of water.

02:16 On the other hand, our ions are going to move more selectively into and out of the cells by way of different carrier or transport proteins found in the cellular membranes.

02:29 Nutrients, waste, and gases usually have a unidirectional flow out of the cell.