B4- organising animals and plants

• What does blood consist of

  • red blood cells
  • White blood cells
  • Platelets
  • Plasma
• What are red blood cells

  • make up half of our blood
  • Carry oxygen from lungs to bodies tissues to use in cellular respiration
• how does blood carry oxygen

  • haemoglobin combines with oxygen
  • once tissues are reaches oxyhemoglobin splits back into haemoglobin and oxygen
  • oxygen is free to diffuse
• adaptations of red blood cells

  • don’t have a nucleus - more space for haemoglobin and oxygen
  • biconcave disk - large surface area to absorb oxygen
• How do white blood cells defend against pathogens

  • phagocytosis - engulfs microorganisms
  • Antibodies - bind onto pathogens
  • Antitoxins - neutralise any toxins
• what are platelets

  small fragments of cells (no nucleus)

  float about in blood
• function of platelets

  • to form clots
  • To form a barrier against microorganisms that could cause infection
• what is plasma

  • what makes blood watery so it can flow
• what does plasma carry

  • red blood cells
  • White blood cells
  • Platelets
  • Nutrients (glucose and amino acids)
  • Waste products (co2, urea)
  • Hormones
  • Proteins
  • Antibodies
  • Anti toxins
• Function of each blood vessels

  Arteries– carry blood away from heat

  Capillaries - exchange nutrients and oxygen with tissues

  Veins- Carry blood into heart
• what do arteries Do

  Carry very high pressure blood away from heart to organs
• Structure of arteries

  • thick muscular walls - withstand high blood pressure
  • elastic fibres stretch when the surge of blood passes through and then recoil in between surges - keeps blood moving
• function of capillaries

  To diffuse substances such as glucose and oxygen into cells

  C02 diffuses from cells back into blood
• adaptations of capillaries

  • very thin walls - short diffusion path
• function of veins

  to transport blood from organs back to the heart slowly and at low pressure
• Adaptation of veins

  • Thin wall - blood pressure is low so wall doesn’t need to be thick
  • Valves to prevent backflow - when blood flows in correct diretion valves open, if it flows backwards they shut
• What is a double circulatory system

  Where blood passes through the heart twice

  Heart - lungs - heart - organs - heart
• Benefit of double circulatory system

  Allows for higher pressure and rapid delivery of oxygen and nutrients to body cells
• What is the heart

  an organ of muscle tissue - pumps blood around the body
• What are the chambers of the heart

  left atrium (top right)

  Right atrium (top left)

  Left ventricle (bottom right)

  Right ventricle (bottom left)
• What separates the atria and ventricles

  Valves
• What is the function of the vena cava

  Bring deoxygenated blood from the body to the heart - right atrium
• function of pulmonary artery

  Deoxygenated blood passes from heart to lungs - right ventricle
• Function of pulmonary vein

  Bring oxygenated blood from lungs into heart - left atrium
• Function of aorta

  Oxygenated blood Pumped from heart to the body in the aorta - left ventricle
• order of blood

  • enters left atrium (from lungs) and right Atrium (from body)
  • Atria contract and blood is forced into ventricles
  • Ventricles contract and blood is forced out Of the heart
  • Valves stop blood from black flowing into atria when ventricles contract
• Why is the left sides wall thicker

  • left ventricle pumps blood around entire body
  • Needs a greater force
  • Right ventricle only pumps blood to lungs
• Where are the coronary arteries

  Branch out of aorta and spread into heart muscles
• Purpose of coronary artery

  Provide oxygen to muscle cells of the heart

  Oxygen used in respiration to provide energy for contractions
• What is heart rate controlled by

  Pacemaker - group of cells in right atrium
• What is an artificial pacemaker

  Small electrical device which corrects irregularities in heart rate
• What are cardiovascular diseases

  Diseases of heart and blood vessels

  Non-communicable

  Not infectious
• What is coronary heart disease

  • layers of fatty material build up in coronary arteries
  • Causes coronary arteries to narrow
  • Reduces flow of blood
  • Lack of oxygen for heart muscles
  • Can lead to a heart attack where heart is starved of oxygen
• What are statins

  • drugs which reduce cholesterol levels in blood
  • Slows down rate fatty materials build up
• advantages of statins

  • proven to reduce risk of coronary heart disease
• disadvantages of statins

  • unwanted Side effects - liver problems
• what are stents

  • when there is almost a total blockage of coronary arteries
  • A tube which is inserted into artery to keep it open
  • Blood can flow normally through artery
  • will not prevent other regions of coronary artery for narrowing
  • Does nit treat underlying cases of disease
• Diseases caused by heart valves

  • valves do not fully open so heart has to pump harder
  • Can cause heart to enlarge
  • Valves are leaky - weak and tired
• valves replacements

  • metal (mechanical) or from and animal such as a pig
  • mechanical valves can last a lifetime but increase risk of blood clots - patients have to take anti clotting drugs
  • Animal valves do not last long ad need to be replaced - do not need to take drugs
• What is heart failure

  When the heart cannot pump enough blood around the body

  Need a donated heart (+lungs)