Blood Pressure : Salt's effects on your body
lower osmotic pressure = more fluid retention in blood = higher blood pressure. strated the reciprocal relationship between plasma colloid the colloid osmotic pressure of tissue fluids has been . effect of blood pressure changes on fluid move- ment through the . vascular volume for reasons explained earlier. This was. To do this, your kidneys use osmosis to draw the extra water out of your blood. This process uses a delicate balance of sodium and potassium to pull the water.
The key to remember about osmosis is that water flows from the solution with the lower solute concentration into the solution with higher solute concentration. This means that water flows in response to differences in molarity across a membrane. The size of the solute particles does not influence osmosis.
Equilibrium is reached once sufficient water has moved to equalize the solute concentration on both sides of the membrane, and at that point, net flow of water ceases. Here is a simple example to illustrate these principles: Two containers of equal volume are separated by a membrane that allows free passage of water, but totally restricts passage of solute molecules.
Solution A has 3 molecules of the protein albumin molecular weight 66, and Solution B contains 15 molecules of glucose molecular weight Into which compartment will water flow, or will there be no net movement of water? Tonicity When thinking about osmosis, we are always comparing solute concentrations between two solutions, and some standard terminology is commonly used to describe these differences: The solutions being compared have equal concentration of solutes.
The solution with the higher concentration of solutes. The solution with the lower concentration of solutes. Diffusion of water across a membrane generates a pressure called osmotic pressure.
If the pressure in the compartment into which water is flowing is raised to the equivalent of the osmotic pressure, movement of water will stop. This pressure is often called hydrostatic 'water-stopping' pressure.
The term osmolarity is used to describe the number of solute particles in a volume of fluid. Osmoles are used to describe the concentration in terms of number of particles - a 1 osmolar solution contains 1 mole of osmotically-active particles molecules and ions per liter.
The classic demonstration of osmosis and osmotic pressure is to immerse red blood cells in solutions of varying osmolarity and watch what happens. Blood serum is isotonic with respect to the cytoplasm, and red cells in that solution assume the shape of a biconcave disk.
To prepare the images shown below, red cells from your intrepid author were suspended in three types of solutions: Isotonic - the cells were diluted in serum: Note the beautiful biconcave shape of the cells as they circulate in blood.
Hypotonic - the cells in serum were diluted in water: Identify the primary mechanisms of capillary exchange Distinguish between capillary hydrostatic pressure and blood colloid osmotic pressure, explaining the contribution of each to net filtration pressure Compare filtration and reabsorption Explain the fate of fluid that is not reabsorbed from the tissues into the vascular capillaries The primary purpose of the cardiovascular system is to circulate gases, nutrients, wastes, and other substances to and from the cells of the body.
Small molecules, such as gases, lipids, and lipid-soluble molecules, can diffuse directly through the membranes of the endothelial cells of the capillary wall. Glucose, amino acids, and ions—including sodium, potassium, calcium, and chloride—use transporters to move through specific channels in the membrane by facilitated diffusion. Glucose, ions, and larger molecules may also leave the blood through intercellular clefts. Larger molecules can pass through the pores of fenestrated capillaries, and even large plasma proteins can pass through the great gaps in the sinusoids.
Some large proteins in blood plasma can move into and out of the endothelial cells packaged within vesicles by endocytosis and exocytosis. Water moves by osmosis. Bulk Flow The mass movement of fluids into and out of capillary beds requires a transport mechanism far more efficient than mere diffusion.
This movement, often referred to as bulk flow, involves two pressure-driven mechanisms: Volumes of fluid move from an area of higher pressure in a capillary bed to an area of lower pressure in the tissues via filtration. In contrast, the movement of fluid from an area of higher pressure in the tissues into an area of lower pressure in the capillaries is reabsorption.
Two types of pressure interact to drive each of these movements: Hydrostatic Pressure The primary force driving fluid transport between the capillaries and tissues is hydrostatic pressure, which can be defined as the pressure of any fluid enclosed in a space. Blood hydrostatic pressure is the force exerted by the blood confined within blood vessels or heart chambers. Even more specifically, the pressure exerted by blood against the wall of a capillary is called capillary hydrostatic pressure CHPand is the same as capillary blood pressure.
CHP is the force that drives fluid out of capillaries and into the tissues.
What is the relationship between blood pressure and osmotic pressure regarding? | Yahoo Answers
As fluid exits a capillary and moves into tissues, the hydrostatic pressure in the interstitial fluid correspondingly rises. This opposing hydrostatic pressure is called the interstitial fluid hydrostatic pressure IFHP. Generally, the CHP originating from the arterial pathways is considerably higher than the IFHP, because lymphatic vessels are continually absorbing excess fluid from the tissues.
Thus, fluid generally moves out of the capillary and into the interstitial fluid. This process is called filtration. Osmotic Pressure The net pressure that drives reabsorption—the movement of fluid from the interstitial fluid back into the capillaries—is called osmotic pressure sometimes referred to as oncotic pressure.
Whereas hydrostatic pressure forces fluid out of the capillary, osmotic pressure draws fluid back in. Osmotic pressure is determined by osmotic concentration gradients, that is, the difference in the solute-to-water concentrations in the blood and tissue fluid.
A region higher in solute concentration and lower in water concentration draws water across a semipermeable membrane from a region higher in water concentration and lower in solute concentration. As we discuss osmotic pressure in blood and tissue fluid, it is important to recognize that the formed elements of blood do not contribute to osmotic concentration gradients.
Rather, it is the plasma proteins that play the key role. Solutes also move across the capillary wall according to their concentration gradient, but overall, the concentrations should be similar and not have a significant impact on osmosis. Because of their large size and chemical structure, plasma proteins are not truly solutes, that is, they do not dissolve but are dispersed or suspended in their fluid medium, forming a colloid rather than a solution.
The pressure created by the concentration of colloidal proteins in the blood is called the blood colloidal osmotic pressure BCOP.
Its effect on capillary exchange accounts for the reabsorption of water.
The plasma proteins suspended in blood cannot move across the semipermeable capillary cell membrane, and so they remain in the plasma. As a result, blood has a higher colloidal concentration and lower water concentration than tissue fluid. It therefore attracts water. We can also say that the BCOP is higher than the interstitial fluid colloidal osmotic pressure IFCOPwhich is always very low because interstitial fluid contains few proteins.