TOPIC 8

• Blood is a tissue that has red blood cells, white blood cells, platelets and plasm
• Red blood cells carry oxygen around the body.
• Platelets are involved with clotting to stop bleeding when we get injured.
• White blood cells engulf and produce antibodies
• red blood cells don’t have nucleus for more oxygen space
• Arteries carry blood away from the heart
• arteries have : Thick walls, walls that are strong and elastic
• Arteries carry oxygenated blood except pulmonary artery
• Capillaries connect arteries and veins
• capillaries are very narrow and the wall is one cell thick
• Capillaries have permeable walls for substance to diffuse
• Veins carry blood back to the heart
• veins have thin walls and bigger lumen
• Veins have valves to prevent back flow of blood
• Veins carry deoxygenated blood except pulmonary vein
• Right atrium is the pacemaker
• More muscle on left side of heart to pump blood around the body
• Cornary artery supplies oxygen to heart muscle
• Aorta sends oxygenated blood around the body
• vena cava receives deoxygenated blood
• Faulty valves can be replaced by biological or mechanical valves
• cardiac output = heart rate x stroke volume
• heart rate is number of times it contracts per minute
• Heart pumps blood in a double circulatory system
• metabolism is the sum of all reactions in a cell or body
• repeat experiment at different temperatures
• the extra amount of oxygen required to remove all lactic acid from the cells is the oxygen debt
• during exercise the heart rate, breathing rate and breathing volume increases
• respiration is an exothermic reaction that releases energy for metabolic reactions
• anaerobic respiration releases less energy
• liver oxidises lactic acid and converts it back into glucose
• soda lime absorbs carbon dioxide produced by organism
• diffusion is the net movement of particles from an area of high concentration to an area of low concentration
• shorter diffuse distance, large surface area to volume ratio and increased concentration gradient
• Plasma transports hormones, waste, cells and carbon dioxide
• Anaerobic 


  Glucose ---> Lactic acid
• if surface area : volume ratio decreases the rate of diffusion slows down
• Arteries have elastic fibers that stretch for blood to enter
• Soda lime used in experiment to measure volume decrease when oxygen is getting used up
• Temperature affects the rate of respiration and is an independent variable