Tissue Fluid Formation Flashcards
(20 cards)
What is a tissue?
A group of cells with the same function.
What is the tissue fluid?
The liquid that surrounds the cells in your body.
What is the tissue fluid composed of?
Water, glucose, amino acids, fatty acids, ions and oxygen.
Describe the formation of tissue fluid.
At the arteriole end of capillaries:
1. There is a hydrostatic pressure inside capillaries (due to
contraction of ventricles) than tissue fluid (so net outward force)
2. Forcing water (and dissolved substances) out of capillaries
3. Large plasma proteins remain in capillary
How are molecules forced out of the capillaries?
The capillaries have small gaps in their walls.
What is the process of tissue fluid formation also known as?
Ultrafiltration
What are 3 molecules that are too large to be forced out?
Platelets
Red blood cells
Large proteins
Why is tissue fluid not red in colour?
There are no red blood cells.
Explain the return of tissue fluid to the circulatory system.
At the venule end of capillaries:
1. Hydrostatic pressure reduces as fluid leaves capillary (also due to friction)
2. (Due to water loss) an increasing concentration of plasma proteins lowers water potential in
capillary below that of tissue fluid
3. Water enters capillaries from tissue fluid by osmosis down a water potential gradient
4. Excess water taken up by lymph capillaries and returned to circulatory system through veins.
How is a low water potential established in the capillaries?
Large molecules remain in the capillaries and thus create a lower water potential.
What is meant by the venule end?
The venule end is the end of the capillary bed that is nearest to the veins.
How does the waste in the blood get into the blood to be removed from the body?
Water re-enters the capillaries by osmosis.
Within the water, there’ll be dissolved waste molecules such as carbon dioxide and urea.
They are then reabsorbed with the water by osmosis back into the blood.
What happens if water isn’t reabsorbed?
If it isn’t reabsorbed, you’ll run out of liquid in your blood and your cells will become covered in so much liquid that you’ll see swellings in your body.
Suggest and explain causes of excess tissue fluid accumulation.
1)Low concentration of protein in blood plasma
○ Water potential in capillary not as low → water potential gradient is reduced
○ So more tissue fluid formed at arteriole end / less water absorbed at venule end by osmosis
○ Lymph system may not be able to drain excess fast enough
2)High blood pressure (eg. caused by high salt concentration) → high hydrostatic pressure
○ Increases outward pressure from arteriole end AND reduces inward pressure at venule end
○ So more tissue fluid formed at arteriole end / less water absorbed at venule end by osmosis
○ Lymph system may not be able to drain excess fast enough
Why won’t all the tissue fluid be reabsorbed back into the capillary?
Because eventually equilibrium will be reached - osmosis.
How will the rest of the tissue fluid be absorbed when equilibrium is reached?
The rest of the tissue fluid is absorbed into the lymphatic system and eventually drains back into the bloodstream near the heart.
What system is used when equilibrium is reached?
Lymphatic system
What does the lymphatic system have that is similar to veins?
Lymph vessels. They have valves.
What is a risk factor?
An aspect of a person’s lifestyle or substances in a person’s body / environment. That have been shown to be linked to an increased rate of disease
Give examples of risk factors for cardiovascular disease.
Age.
Diet in high salt or saturated fat.
Smoking.
Lack of exercise.
Genes.
