circulatory system

• red blood cell carry oxygen with haemoglobin
• red blood cell have no nucleus
• white blood cells are phagocytes, lymphocytes and granulocytes
• platelets clot the blood
• biconcave shape - larger surface area
• red blood cell is the most abundant cell in the blood
• oxygenated red blood cells are bright red
• haemoglobin binds to oxygen molecules
• the biconcave shape allows more haemoglobin to be packed into the cell
• macrophages defend pathogen
• phagocytosis is to engulf pathogen
• antitoxin neutralise toxins (made by bacteria)
• lymphocytes produce antibodies
• antibodies kill pathogen
• white blood cells have nucleus
• platelets are cell fragments
• platelets clot scab at wound
• plasma carry urea, blood cells, hormones, CO2, amino acid, glucose
• plasma is yellow
• arteries carry oxygenated blood
• veins carry deoxygenated blood
• capillaries exchange nutrients with tissues
• heart has four chambers
• human have double circulatory system
• left right switch in the diagram (imagine a person facing you, their left is my right)
• right atrium receives deoxygenated blood from vena cavae
• upper chambers are atrium
• lower chambers are ventricles
• vein - blood vessels that bring blood into the heart through atrium
• vena cava (vein)- bring deoxygenated blood into the right atrium
• valve separate atrium and ventricle
• valve prevent blood flowing backward
• elastic fibres in arteries- stretch/recoil (to withstand pressure)
• smooth muscle in arteries - contract (to change blood flow)
• narrow lumen in arteries - keeps the pressure at quite high level
• high blood pressure in arteries
• arteries move away from heart (transfer oxygen to body parts)
• veins have lower blood pressure (than arteries)
• vein have thinner elastic fibres & muscle (than arteries)
• valves in veins prevent backflow of blood