How do substances move through capillary walls?
How do substances move through capillary walls?
Capillaries therefore allow molecules to diffuse across the capillary walls….Exchange of molecules
- Oxygen diffuses through the capillary wall, into the tissue fluid and the cells.
- Carbon dioxide diffuses from the cells into the tissue fluid, then across the capillary walls into the blood plasma .
What causes liquid to flow out of the capillaries?
Hydrostatic Pressure CHP is the force that drives fluid out of capillaries and into the tissues. As fluid exits a capillary and moves into tissues, the hydrostatic pressure in the interstitial fluid correspondingly rises.
What is the fluid forced out of capillary beds?
20 Cards in this Set
| Lymph fluid and some plasma proteins originate (escape) from the | Blood Plasma |
|---|---|
| The fluid that is forced out of the capillary beds by hydrostatic and osmotic pressures and into the tissue spaces is called | Lymph |
| Lymph flows | Toward the heart only |
How do hydrostatic and osmotic pressures determine fluid movement across the walls of capillaries?
Hydrostatic and osmotic pressure determine fluid movement across capillaries by raising and lowering the pressure within cells. If there is less pressure on the interior of the capillary, the greater pressure on the outside of the exterior of the capillary will influence water to diffuse inside.
What substances Cannot move across capillary walls?
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.
Does all the fluid that leaves the blood at the arterial end return at the venous end?
the net filtration pressure of the blood is higher at the arterial end than it is at the venous end. The fluids reenter the capillaries at the venous end because… the net filtration pressure of the blood is higher at the arterial end than it is at the venous end.
Why would the osmotic pressure be low in someone who is starving?
In starvation, the formation of plasma proteins is reduced and therefore the protein osmotic pressure may not be sufficient to keep fluids inside the blood stream. The level of plasma proteins becomes low, and the fluid forces in the capillaries become unbalanced.
Which layer of the blood vessel wall is responsible for vasoconstriction?
tunica media
The tunica media is the layer of an artery which is responsible for vasoconstriction and vasodilation. Within this layer the vessel wall is smooth muscle. When the smooth muscle contracts, that is called vasoconstriction and the diameter of the artery decreases.
How is fluid transported between capillaries and tissues?
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.
How does hydrostatic pressure affect the flow of fluid in the capillary?
Hydrostatic pressure is the force generated by the pressure of fluid within or outside of capillary on the capillary wall. The net filtration pressure derived from the sum of the four forces described above determines the fluid flow into or out of the capillary.
Which is a form of osmotic pressure generated by the capillary walls?
Oncotic pressure is a form of osmotic pressure exerted by proteins either in the blood plasma or interstitial fluid. Hydrostatic pressure is a force generated by the pressure of fluid on the capillary walls either by the blood plasma or interstitial fluid.
What should the pressure be at the arterial end of the capillary bed?
Thus, even at the arterial end of the capillary bed, the net filtration pressure would be below 10 mm Hg, and an abnormally reduced level of filtration would occur. In fact, reabsorption might begin to occur by the midpoint of the capillary bed. False.