Circulatory system and the Blood Flashcards
What main 4 components make up the blood?
Plasma, platelets, white blood cells, red blood cells
What is a plasma?
A pale yellow liquid which carries things around the body.
What does the plasma transport?
CO2
Urea
Hormones
Nutrients
Amino acids
Heat energy
What are platelets?
Small fragments of cells that help blood clot.
Explain the process of blood clotting.
They release chemicals when the blood is exposed to air, which cause soluble fibrinogen to be converted to insoluble fibrin. Fibrin forms a mesh, which traps platelets and red blood cells to form a clot.
What are the types of white blood cells?
Phagocytes
Lymphocytes
What is the function of red blood cells?
Transport oxygen around the body
Bind to haemoglobin
How are red blood cells specialised for their job?
They contain haemoglobin which combines with oxygen to form oxyhaemoglobin which transports oxygen to respiring cells.
They have no nucleus so more haemoglobin can be packed into each cells so more oxygen can be transported.
Biconcave shape
How does the biconcave shape help a red blood cell?
Increases their surface area: volume ratio and decreases the distance to the centre of the cell which increases the rate of diffusion.
What are phagocytes?
Larger cells with a multi-lobed nucleus
Engulf and digest pathogens
What are lymphocytes?
Cells with a very large nucleus
Make and release antibodies, which bind to and destroy pathogens.
What is a pathogen?
A microorganism that can cause disease.
How do phagocytes fight pathogens?
Phagocytes detect things that are foreign body. They then engulf the pathogens and digest them.
Phagocytes are non-specific - they attack anything that’s not meant to be there.
How do lymphocytes fight pathogens?
When lymphocytes come across a foreign antigen they start to produce antibodies.
These lock on to the invading pathogens and mark them out for destruction by other white blood cells.
Antibodies are then produced rapidly and flow around the body to mark all similar pathogens.
Memory cells are also produced in response to a foreign antigen. They can reproduce very fast if the same antigen enters the body again.
How do vaccinations protect from future infections?
Vaccinations involve injecting dead or inactive pathogens into the body. They are harmless but still have antigens so the body can produce antibodies to attack them.
Memory cells will be produced so if a similar pathogen enters the body again the body knows how to combat it.
What are the three types of blood vessels?
Arteries
Capillaries
Veins
What is the function of the artery?
Can transport blood at high pressure without bursting
Allows artery to stretch and recoil to keep blood flowing at high pressure.
Helps to control flow of blood by widening and narrowing.
What is the function of capillaries?
Short diffusion distance of substance from blood into tissues
What is the function of the vein?
Blood is flowing at lower pressure so thick wall not needed
Prevents blood flowing backwards.
What is the structure of the artery?
Thick outer wall
Thick layer of elastic tissue
Thick layer of muscular tissue
What is the structure of a vein?
Fairly thin outer wall
Thin layer of muscle and elastic tissue
Semilunar valves
What is the structure of a capillary?
Wall is one cell thick
The right atrium of the heart receives ________________ blood from the body through the _______ ______
deoxygenated
vena cava
The deoxygenated blood from the right atrium moves through to…
the right ventricle which pumps it to the lungs via the pulmonary artery.
