chap 5 transport in humans

• what are the main components of blood ?

  plasma, red blood cells, white blood cells and platelets
• what does plasma contain ?

  
  

  • mainly water and substances such as glucose, salts, proteins, amino acids, fats, vitamins, hormones and excretory products like urea
  • red and white blood cells
• what does plasma transport ?

  • blood cells around the body
  • nutrients from the small intestines to other parts of the body
  • excretory products from the organs where they are produced to excretory organs for removal
  • hormones from endocrine glands to target organs
• what is the main function of red blood cells ?

  transport oxygen from the lungs to the other parts of the body
• what are some adaptations of rbc ?

  • circular, biconcave shape
  • no nucleus
  • contain haemoglobin
  • flexible
• explain how haemoglobin in rbc is useful in transporting oxygen

  • haemoglobin combines reversibly with oxygen in the lungs to form oxyhaemoglobin
  • it can then release its oxygen to tissue cells where oxygen concentration is low
• explain how biconcave shape is useful for rbc

  it can increase the surface area to volume ratio, increasing the rate of absorption and release of oxygen
• explain how flexibility in rbc is useful

  it can change into a bell- shaped structure so that they can flow easily through narrow blood capillaries
• explain how having no nucleus is useful in rbc

  there is more space for more haemoglobin to be stored
• what are the 2 main types of wbc ?

  phagocytes and lymphocytes
• what is the function of phagocytes ?

  to perform phagocytosis
• what is phagocytosis ?

  it is the process by which a wbc engulfs and destroys foreign particles such as bacteria
• what is the function of lymphocytes ?

  to produce antibodies
• what does the antibodies that lymphocytes produce do ?

  • recognise foreign particles
  • destroy disease- causing organisms such as bacteria and viruses
  • cause bacteria to clump together for easy ingestion by phagocytosis
  • neutralise the toxins produced by bacteria
• how does blood clot ?

  • when there is a open wound or cut, the platelets are stimulated to convert the soluble fibrinogen to insoluble fibrin threads through a process that involves enzymes
  • the fibrin threads entangle blood cells, forming a clot
  • this seals the wound, preventing pathogens from entering and excessive loss of blood
• what does the surface of the rbc contain ?

  the surface of rbc contain proteins called antigens
• what are antigens represented by ?

  A
• what does A represent ?

  antigens
• what represents antibodies ?

  a
• what does a represent ?

  antibodies
• what antigens and antibodies does blood group A have ?


  antigen A

  antibody b
• what antigens and antibodies does blood group B have ?

  antigen B

  antibody a
• what antigens and antibodies does blood group AB have ?

  antigen A and B

  no antibody
• what antigens and antibodies does blood group O have ?

  no antigens

  antibodies a and b
• what happens if blood groups of different antigens mix ?

  the blood would agglutinate
• which blood group is a universal donor ?

  blood group O
• which blood group is the universal receiver ?

  blood group AB
• blood vessels transporting away from heart from big to small

  arteries -> arterioles -> blood capillaries
• blood vessels transporting towards the heart from big to small

  veins -> venules
• what are some features of arteries and how does help with its function ?

  • they have thick, muscular and elastic walls
  • withstand the high blood pressure in the artery
  • enables it to stretch and recoil, helping to push the blood in spurts along the artery
  • this also gives rise to the pulse
• what are some features of veins and how does it help with its function ?

  • have internal valves to prevent backflow of blood as blood flows more slowly and smoothly
• what is the colourless liquid in the tiny spaces between tissue cells ?

  it is the tissue fluid which transports dissolved substances between the tissue cells and blood capillaries
• what substances diffuse into tissue fluid ?

  dissolved food substances and oxygen diffuse from the blood in the blood capillaries into the tissue fluid
• what substances diffuse out of tissue fluid ?

  • waste products diffuse from the cells into the tissue fluid and are transferred through the blood capillary walls into the blood
  • the blood transports these waste products to the excretory organs for removal
• which side of the heart transport oxygenated blood ?

  left side
• why are the walls of the left ventricle thicker than the right ?

  • the left ventricle pumps blood around the whole body and this requires high pressure, hence requires thicker walls to be able to withstand it
  • the right ventricle only pumps blood to the lungs which is close to the heart
• why are the walls of the ventricle thicker than atria ?

  atria only force blood into the ventricles that are directly below them, not requiring high pressure
• what is the function if the median septum ?

  • it is a muscular wall that separates the right and left sides of the heart
  • this prevents mixing of deoxygenated blood in the right side with oxygenated blood in the left side
  • the mixing of oxygenated and deoxygenated blood will reduce the amount of oxygen carried to the rest of the body
• what is the valve in the left side of the heart ?

  bicuspid valve
• what is the valve in the right side of the heart ?

  tricuspid valve