11.4 Blood (Cambridge (CIE) O Level Biology): Flashcards
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- FrontComponents of Blood
What are the four main components of blood?
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Cards in this collection (24)
What are the four main components of blood?
The four components are:
red blood cells
white blood cells
platelets
plasma
Define tissue fluid.
The fluid formed when plasma is forced out of the capillaries to surround and bathe the body's cells.
Define plasma.
The clear, straw-coloured liquid that transports blood cells and dissolved substances around the body.
How is tissue fluid formed?
As blood passes through the capillaries, some plasma is forced out under pressure through gaps in the capillary walls.
How are red blood cells adapted to carry oxygen?
They are biconcave discs with no nucleus, maximising space for the protein haemoglobin.
How does the composition of tissue fluid differ from plasma?
It is virtually the same, but tissue fluid contains far fewer proteins.
How can red and white blood cells be told apart under a microscope?
Red blood cells are biconcave with no nucleus; white blood cells are round with a nucleus.
Why does tissue fluid contain fewer proteins than plasma?
Proteins are too large to fit through the gaps in the capillary walls, so they stay in the blood.
Red blood cells carry oxygen in the form of .
Red blood cells carry oxygen in the form of oxyhaemoglobin.
Tissue fluid is formed when plasma is forced out of the .
Tissue fluid is formed when plasma is forced out of the capillaries.
What is the function of lymphocytes?
They produce antibodies to defend the body against pathogens.
What is the role of tissue fluid?
It allows the exchange of substances between the blood and the body's cells.
What is the function of phagocytes?
They carry out phagocytosis, engulfing and digesting pathogens.
Give an example of a substance exchanged via tissue fluid.
Carbon dioxide leaves a cell, dissolves in the tissue fluid, then diffuses into the capillary.
Define platelet.
A fragment of a cell involved in blood clotting.
The exchange of substances between cells and the blood takes place via the .
The exchange of substances between cells and the blood takes place via the tissue fluid.
How do platelets help to form a blood clot?
They release chemicals that convert soluble fibrinogen into insoluble fibrin, forming a mesh that traps red blood cells.
Define plasma.
The straw-coloured liquid, mostly water, that makes up about 55% of the blood.
During clotting, soluble fibrinogen is converted into insoluble .
During clotting, soluble fibrinogen is converted into insoluble fibrin.
True or False?
Blood directly bathes the body's cells.
False.
Blood stays within the vessels; tissue fluid bathes the cells.
True or False?
Red blood cells contain a nucleus.
False.
Red blood cells have no nucleus, leaving more room for haemoglobin.
True or False?
Tissue fluid contains fewer proteins than plasma.
True.
Proteins are too large to pass through the capillary walls, so tissue fluid has fewer proteins.
True or False?
White blood cells defend the body against infection by pathogens.
True.
Lymphocytes produce antibodies and phagocytes engulf pathogens.
Water is a good , so many substances can dissolve in plasma and be transported.
Water is a good solvent, so many substances can dissolve in plasma and be transported.
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