Exchange in the Capillaries Flashcards
What is blood?
The fluid used to transport materials around the body.
What is hydrostatic pressure?
The pressure that a fluid exerts when pushing against the sides of a vessel or container.
What is lymph?
The fluid held in the lymphatic system.
What is the lymphatic system?
A system of tubes that returns excess tissue fluid to the blood system.
What is oncotic pressure?
The pressure created by the osmotic effects of the solutes.
What is plasma?
The fluid portion of the blood.
What is tissue fluid?
The fluid surrounding the cells and tissues.
What does the plasma contain dissolved in it?
Oxygen, carbon dioxide, minerals, glucose, amino acids, hormones and plasma proteins.
What are the cells that you would find in the plasma?
Erythrocytes, red blood cells
Leucocytes, various white blood cells
Platelets.
How is tissue fluid formed?
By plasma leaking from the capillaries.
What does the tissue fluid do?
Supplies cells in the tissue with the oxygen and nutrients that they require.
The movement of plasma into tissue fluid is what?
Mass flow.
Describe the order of blood vessels through an organ.
Arteries Arterioles Capillaries Venules Veins
At the arterial end of the capillary what is the pressure like?
The hydrostatic pressure is very high.
What does the hydrostatic pressure do to the blood plasma?
It pushes it out of the capillaries into the cells of the tissue and turns into tissue fluid.
Why are red blood cells not pushed out due to the hydrostatic pressure?
They are to large to pass through the capillary membrane.
Why does tissue fluid surround the body cells?
So that the exchange of gases and nutrients can occur across the plasma membrane.
Not all tissue re-enters the blood. Where does it go?
Some tissue fluid is directed into another tubular system called the lymphatic system.
What does the lymphatic system do?
Drains excess tissue fluid out of the tissue and returns it to the blood system via the subclavian vein in the chest.
What is the fluid in the lymphatic system called?
Lymph
What does lymph contain more of than tissue fluid?
Lymphocytes as they are produced in the lymph nodes.
What are lymph nodes and what are they involved in?
They are swellings found at intervals along the lymphatic system, which have an important role in the immune system.
What happens regarding the lymph nodes and capillaries if a tissue is infected?
The capillaries become more leaky and release larger amounts of tissue fluid, which is then directed into the lymphatic system. This helps direct bacteria towards the lymph nodes.
The hydrostatic pressure of blood does what?
Pushes fluid out into the tissues.
The hydrostatic pressure of the tissue fluid does what?
Tends to push fluid into the capillaries.
The oncotic pressure of blood does what?
Tends to pull water back into the blood.
What does the oncotic pressure of the tissue fluid do?
Pulls water into the tissue fluid.
