Tissue Fluid Flashcards
What is tissue fluid?
The fluid which surrounds cells
What does tissue fluid contain?
-Water
-O2
-CO2
-Nutrients
-Electrolytes/ions
-Hormones
-Urea (liver only)
-WBC’s and antibodies (if infection)
What does tissue fluid not contain?
-RBC’s/platelets
-Large plasma proteins as they are too big to leave capillaries
How do cells interact and use tissue fluid?
Take in substances needed from the tissue fluid and release waste into it such as CO2
How is tissue fluid formed?
Fluid is forced out of capillaries by pressure filtration because the hydrostatic pressure inside the capillaries is higher than in the surrounding tissues
What is the first way in which tissue fluid is reabsorbed?
Some is reabsorbed due to oncotic pressure
What is Oncotic pressure?
Where plasma proteins inside capillaries generate a low water potential inside the capillaries so fluid enters by osmosis
What is the second way in which tissue fluid is reabsorbed?
Some is returned via the lymphatic system which is screened by lymphocytes en route
What would be caused by some of this tissue fluid if it was left behind?
Cause swelling/oedema increasing the pressure inside tissues and blood volume/pressure would decrease.
What is the tissue fluid called when inside the lymphatic system?
Lymph
What is one benefit of the lymphatic system?
It can be ‘screened’ by lymphocytes whilst in the lymphatic system. Happens mostly at the lymph nodes
Why do lymph vessels have valves?
To prevent backflow
Why do lymph vessels have a thin layer of smooth muscle in their walls?
To help lymph flow
How does lymph re-enter the blood?
Via the subclavian vein due to oncotic pressure
What does this mean for the lymph?
The blood pressure and volume is restored just before entering the heart
