Transport in humans- topic 3

• Platelets are involved in blood clotting which prevents blood loss and the entry of micro-organisms
• Vaccination results in the manufacture of memory cells which enable future antibody production to the pathogen to happen sooner faster and in greater quantity
• Heart rate increases because when you exercise your muscles need more energy to contract so cells will respire more requiring energy, to get more glucose and oxygen to cells the heart beats faster
• artery carry’s blood away from the heart, always oxygenated. thick outer wall, small lumen, thick media
• capillariry is where gas exchange takes place. very small lumen, wall is one cell layer, thick
• Factors that increase risk of CHD is high cholestrol levels, diabetes, physical inactivity, unhealthy diet, smoking
• Unicellular organism rely on diffusion as its surface area is large compared to volume so nutrients and other substances can pass quickly through the membrane and around its body
• Veins carry blood to the heart and are always deoxygenated. Thin outer wall, large lumen, thin media
• immune system response to disease lymphocytes recognise proteins on the surface of pathogens called antigens produces antibodies. Phagocytes ingest and destroy pathogens such as bacteria
• Blood is made up of red blood cells, white blood cells, platelets and plasma
• Adrenaline causes an increase in heart rate
• Multicellular organism may not be fast enough to meet cells requirements therefore cannot rely on diffusion alone to supply there cells with substances such as food and oxygen and to remove waste products
• RBCS have a bioconcave shape (increase SA for diffusion) small and flebile (fit through narrow blood vessels) no nucleus (can contain more haemoglobin). Contain haemoglobin (red protein that combines with oxygen) thin membrane (gasses can easily diffuse through)
• Circulation system

  
• the heart

  
• Plasma Transports carbon dioxide from cells to lungs hormones from glands to organs glucose from liver to cells and urea from liver to kidney