Tissue fluid Flashcards
What is tissue fluid?
a substance that surrounds body cells
How does it help cells?
cells get their resources through tissue fluid (it contains glucose, oxygen, small proteins)
What is tissue fluid comparable to?
plasma- the main difference is that tissue fluid does not contain big proteins
How is tissue fluid formed?
-at the arterial end of the capillary, there is a high hydrostatic pressure, and lower osmotic pressure
-this forces plasma out of the capillaries, where it is now called tissue fluid
-towards the venous end, there is lower hydrostatic pressure, and higher osmotic pressure
-big proteins remain in the blood, which lowers the water potential in the capillaries compared to the tissue fluid
-therefore water moves back into the blood by osmosis
-90% of the tissue fluid drains back into the capillary, 10% returns to the blood by the lymphatic system
What can and cannot be in tissue fluid?
can- water molecules, minerals and salts, glucose and urea, small proteins and amino acids
cannot- large proteins, red blood cells, platelets
Difference between the circulatory system and the lymphatic system?
circulatory- blood flows in a closed, continuous loop
lymphatic- lymph flows in an open circuit from tissues to lymphatic vessels
What is lymph?
a generally colourless fluid similar to tissue fluid, but containing MORE lipids and LESS proteins
What does lymph do?
helps to keep the volume of tissue fluid constant
What happens when you are malnourished?
-not enough food results in a lack of protein in the blood
-this means that when the smaller molecules leave with the tissue fluid, there are not enough bigger proteins left behind to lower the water potential of the blood significantly
-this means that tissue fluid does not return to the capillary, causing it to build up
What happens when you have elephantiasis
this means that a parasitic worm/consistent contact with volcanic ash has obstructed the lymphatic vessels, stopping tissue fluid from being drained, so collects in the limbs
