Blood And Tissue Fluid Flashcards
(23 cards)
What does blood consist of (1)
Cells
Red blood cells which transport oxygen
White blood cells which play a role in the immune system
Cell fragments e.g platelets which are involved in clotting
What does blood consist of (2)
Blood cells are suspended in a watery solution called blood plasma
What is in blood plasma
This contains a range of dissolved molecule such as glucose amino acids and mineral ions (Na+)
It also contains dissolved oxygen which diffuses out of red blood cells.
There are also plasma proteins like albumin, fibrinogen and globulins.
What are the functions of the blood (1)
Transport of oxygen to and from respiring cells
Transport of digested food from the small intestine
Nitrogenous waste products from ells to excretory organs
Hormones
What are the functions of the blood (2)
Transport of food molecules from storage compounds to the cells that need them
Transport of platelets to damaged areas
Cells and antibodies involved in immune response
What occurs in the capillaries and what is it called
Fluid passes out of the blood and bathes the tissue cells, this is called tissue fluid
Where does the tissue fluid leave the blood and what does it do
It leaves the blood at parts of the capillary which are near the artery, transferring molecules such as oxygen and glucose to the tissue cells.
Where does the tissue fluid rejoin the bloodstream and what does it do
Waste molecules from the tissue cells then pass into the tissue fluid. And it returns back to the blodstream at parts of the capillary near the vein.
What is present in tissue fluid
It has the same composition as plasma without the red blood cells and plasma proteins.
What occurs at the arterial end of the capillary (pressure)
The blood has just passed through an artery and an arteriole. Because of this the blood at this end is still under relatively high pressure (hydrostatic pressure).
What does hydrostatic pressure do
It tends to force fluid of the blood and into the tissue cells
What causes oncotic pressure and what does it do
In the blood plasma there are plasma proteins which are hydrophilic lowering the water potential of the blood plasma. So because of this there is a tendency of water to move back into the blood by osmosis at the Venus end (oncotic pressure)
What are the relative pressure at the arterial end and what does this do
The hydrostatic pressure is greater than the oncotic pressure.
So tissue fluid is forces out of the capillary through the gaps between the endothelial cells.
What is a feature of the blood cells and plasma proteins
They are too large to leave so they remain in the blood plasma.
What is the relative pressure at the venous end of the capillary and what does this do
The hydrostatic pressure is much lower than the oncotic pressure, so water moves back into the blood by osmosis.
Why is the hydrostatic pressure low at the venous end and oncotic pressure high.
There is a large amount of water that has left the blood however the oncotic pressure is still high due to the plasma proteins in the blood plasma.
How much of the tissue fluid is reabsorbed and what does the other percentage become
90% of the tissue fluid is reabsorbed back into the blood, however the remaining 10% drain into a series of blind-ended vessels called lymph capillaries.
What do the lymph capillaries connect to
They connect into larger lymph vessels which form the lymphatic system
How does the lymph fluid move along
When the lymph vessels are squeezed by skeletal muscles
What is an adaptation of lymph vessels
They have valves to keep lymph fluid moving forward (preventing backflow)
Where does the lymph fluid return to the blood stream
Under the collarbone to the right and left subclavian veins
What is the composition of lymph
It has a similar composition to plasma and tissue fluid but has less oxygen and nutrients and also contains fatty acids.
What is present along the lymph vessels and what builds up in them and what do they do
Lymph nodes. Lymphocytes build up in the lymph nodes and produce antibodies which then pass into the blood. They also intercept bacteria and other debris from the lymph which is digested by phagocytes.
