blood Flashcards
What are the four main components of blood?
- RBC
- WBC
- plasma
- platelets
what is the function of the blood? (four functions)
- transport substances around body
- distribute heat energy around body
- defend against disease
- seals cuts to protects against infection
what is the function of plasma?
carries cells and dissolved substances and helps to distribute heat energy
name some substances that plasma transports
- RBC
- WBC
- platelets
- CO2 and O2
- digested food
- hormones
- waste
- water
what is the function of platelets?
clump together when blood vessel becomes damaged to form clots
describe what happens when you get a cut
- platelets respond by releasing an enzyme that causes the formation of a fibrin
- fibrin traps blood cells to form a clot
- this seals the cut and prevents blood from leaking out and pathogens from getting in
what is the function of an RBC?
transports o2 from the lung to body tissues
how are RBCs adapted for its function?
- biconcave disc shape to increase surface area so more oxygen can be absorbed
- no nucleus so more room for haemoglobin
- can change shape without breaking as it squeezes single file through the capillaries
what is the function of a WBC?
protects body against disease, some produce antibodies, others engulf disease
what is a phagocytes function?
engulf and digest pathogens they find in the bloodstream
describe how a phagocyte engulfs a pathogen
- moves towards pathogen
- cytoplasm surrounds the pathogen
- digestive enzymes released to break down and destroy the pathogen
what is a lymphocytes function?
makes antibodies to attack pathogens
describe how the body protects against disease
- lymphocytes recognise a pathogen by the antigens on its surface
- when recognised, the lymphocytes make antibodies which attach and clamp the pathogens together
- the phagocyte then engulfs and digests pathogens
- digestive enzymes break down pathogens inside the vacuole of phagocyte
- memory cells remember the antigen to react quickly next time
