The Circulatory System

Alternative transcript:

heart muscle with oxygen and nutrients. blood vessels: there are 3 types of blood vessels: 1. arteries: carry blood away from the heart 2. capillaries: exchange materials at the tissues 3. veins: carry blood towards the heart arteries: ARTERIES capillaries: veins: BLOOD VESSELS blood is pumped at a high pressure so the walls are strong and elastic walls are thicker than lumen (hole in between) thick layers of muscle and elastic fibres CAPILLARIES VEINS permeable so substances can diffuse only 1cm thick - increase rate of diffusion as it has less distance supply food and o2 and take waste like co2 lower rate of blood flow 2. white blood cells 3. platelets 4. blood plasma blood is pumped at a low pressure so walks are not as thick big lumens and thin walls to help blood flow valves - ensure blood doesn't flow backwards blood: there are four types of things in the blood: 1. red blood cells red blood cells white blood cells adaptations: red blood cells: role: transport o2 from lungs to rest of body. platelets white blood cells: role: defend body against pathogens methods: large surface area to volume ratio to increase rate of diffusion has a biconcave disc shape so o2 can fit nicely has haemoglobin. when it combines with o2 it becomes oxyhaemoglobin no nucleus - more space small and flexible - easily pass through the capillaries phagocytosis- process which a white blood cell binds to, and then engulfs a pathogen, in order to destroy it. antibodies- bind to pathogens and help immune cell destroy the pathogens. they have a nucleus platelets: role: clot the blood when a blood vessel breaks importance: Prevents blood from leaving the blood vessels Prevents pathogens from entering the blood has no nucleus as platelets are only fragments of cells plasma blood plasma: role: carry substances and cells around the body carries: replacing blood: Lost blood can be replaced in two ways: 1. artificial blood red blood cells, white blood cells, and platelets nutrients: glucose, amino acids, fatty acids and glycerol waste: co2 and urea hormones and antibodies 2. real blood in a blood transfusion artificial blood: salt water solution replaces the volume of liquid that is lost so your heart can continue to pump blood around the body no red blood cells, so can't carry o2 blood transfusion: contains real blood with red blood cells not readily available