biology topic 1

• Solvent


  Substances dissolve in it
• dipolle


  Having a slightly positive charge and negative charge
• Cohesive


  They tend to stick together
• Cohesion


  Attraction between molecules of the same type
• Which side of the heart carries oxygenated blood?


  left
• Why is the left side of the heart thicker?

  Because it carries oxygenated blood
• Where does blood from the vena cava go to?

  Right atrium
• Where does blood from the pulmonary vein go to?

  Left atrium
• Why does the heart have coronary arteries on the surface?

  It needs oxygen it's own supply of oxygen to pump the blood around the body
• What is the valve between the atrium and ventricle?

  Atrioventricular valves
• What is the valve between the right ventricle and the pulmonary artery?

  Semi lunar valve
• What is the valve between the left ventricle and aorta?

  Semi lunar valve
• What do valves do?


  Stop the back flow of blood
• Why do animals have a heart and circulation

  The cells of all living organisms need a constant supply of reactants for metabolism

  
  

  Single-celled organisms can gain oxygen and glucose directly from their surroundings, via diffusion due to short diffusion distances

  
  

  Larger organisms, however, are made up of many layers of cells and have larger energy requirements, meaning that the time taken for substances such as glucose and oxygen to diffuse to every cell in the body would be far too long as the diffusion distances involved are too great

  
  

  To solve this problem their exchange surfaces are connected to a mass transport system (the circulatory system) which is powered by the heart
• What is mass transport

  the bulk movement of gases or liquids in one direction, usually via a system of vessels and tubes
• What do mass transport systems do?

  Bring substances quickly from one exchange site to another.

  
  

  maintain diffusion gradients at exchange sites and between cells and their fluid surroundings

  
  

  Ensure effective cell activity by supplying reactants and removing waste products
• What are the three blood vessels?

  Arteries, veins and capillaries
• What do the arteries do?

  Carry blood from the heart to the rest of the body
• Structure of an artery?

  Thick muscle wall, lots elastic fibres, small lumen
• What are the functional features within an artery

  To withstand the high pressure of the blood, to be able to stretch and recoil
• What do veins do?

  Take blood back to the heart
• Structure of veins?


  Large lumen, thin muscle wall, little elastic tissue
• Why do veins have different features to arteries?

  Veins are different because the blood that goes to them are under lower pressure.
• what is atheroma?


  it is a fatty deposit that makes the lumen get smaller.
• How does atherosclerosis occur?

  1)there is damage to the endothelial wall

  2)this triggers an inflammatory response

  3)white blood cells accumulate with chemicals in the blood

  4)WBC enlarge with cholesterol and form a atheroma

  5)this stretches the artery making it lose elasticity

  6)calcium deposits and fibrous tissue build up forming plaque

  7)lumen size reduces, higher chance of damage
• what does atheroma do?

  it produces postive feedback of the lumen getting smaller ad there being a higher chance of damage to the arteries.
• Explain the process of blood clotting

  1)Platelets in the blood release serotonin and thromboplastin

  2)in the presence of calcium ions, thromboplastin will catalyze with prothrombin to form thrombin.

  3)Thrombin + fibrinogen = fibrin
• what is fibrin used for?

  create the mesh that traps red blood cells.
• explain the link between atherosclerosis and blood clotting

  Atherosclerosis will make the lumen smaller so the chance of blood clotting is increased due to the fatty deposits.
• what are the lifestyle factors that affect CVD?

  Diet, high blood pressure, smoking and inactivity
• explain diet in terms of affecting CVD

  High saturated at diet increases blood cholesterol and atheroma formation.
• explain high blood pressure in terms of affecting CVD

  This increases the risk to the damage of the arterial wall
• how does smoking affect CVD?

  - CO reduces amount of O2 in the blood so not enough o2 can get to tissue > stroke

  - nicotin makes platelets sticky
• how does inactivity affect CVD?

  This increases blood pressure
• what a factors that are beyond control in terms of CVD?

  Genetics, age and gender
• What are antihypertensives?


  drugs that reduce blood pressure
• what are benefits of antihypertensives?

  - They can be given in combination to reduce blood pressure as they work in different ways

  - Blood pressure can be monitored at the home so the patient can see if the drugs are working
• what are risks of hypertensives?

  Could cause fainting, headaches, drowsiness
• What are statins?


  They are drugs which lower the amount of 'bad' cholestrol in blood.
• benefits of statins


  Reduce the risk of developing CVD