Lungs + heart

• function of lungs-Give oxygen to bloodstream where it can then be transported around the rest of the body
• The lungs

  A) Trachea

  B) Bronchus

  C) Bronchiole

  D) Alvoli

  
• Adaptations of alveoli

  • Large surface area
  • Made up of one layer of very thin cells which creates a short diffusion pathway to increase the rate at which carbon dioxide and oxygen can diffuse across( from blood capillaries/into blodd capillaries)
  • Wall is moist to allow gases to dissolve increasing the rate of diffusion
• Gas exchange at the alveolus

  A) Moisture lining

  B) Red blood cell picks up oxygen

  C) Wall is one cell thick

  D) Capillary wall one cell thick

  E) Deoxygenated

  F) Blood from the heart

  G) High oxygen concentration

  H) Oxygenated

  I) Low carbon dioxide concentration

  
• Circulatory system- transports oxygen and nutrients to our body's tissues
• Blood vessels- network of tubes that carry blood throughout the circulatory system
• Arteries- carry blood away from the heart, have thick walls with elastic tissue to cope with high pressure.
• Veins- return deoxygenated blood back to the heart, thinner than arteries as they don’t need to cope with high pressures.
• Circulatory system relies on

  1. The blood to carry oxygen and nutrients
  2. Blood vessels to hold the blood
  3. The heart to pump the blood to keep it moving through the vessels
• Double circulatory system-For every heartbeat the heart pumps blood to body cells and lungs at the same time
• Double circulatory system

  A) Oxygenated blood

  B) Deoxygenated blood

  C) The heart

  D) Pulmonary vein

  
• The heart

  A) Valves

  B) Pulmonary vein

  C) Aorta

  D) Ventricle

  E) Chamber

  F) Muscular wall

  G) Vena cava

  H) pulmonary arterry

  
• The heart is made out of cardiac muscle
• The heart is a double pump that squeezes the blood around the body and to the lungs to pick up oxygen.
• Right side of the heart pumps blood to the lungs to pick up oxygen
• The left side of the heart pumps blood around the rest of the body
• Pulmonary vein brings oxygenated blood from the lungs
• Left ventricle is the chamber with the thickest muscle
• Atria receives blood from veins
• Valves prevent backflow of blood
• Aorta takes oxygenated blood to the body
• Vena cava brings deoxygenated blood from the body to the heart
• Coronary heart disease:

  • Coronary arteries ( which supply blood to the heart muscle) begin to get blocked
  • This is due to a build-up of fatty materials in the lining of the vessels
  • This causes the lumen to become narrower so less blood can flow through
  • If blood flow to the coronary arteries is stopped the supply of oxygen to the heart muscle is reduced
  • This can cause pain,heart attacks or death
• Risk factors for CHD include smoking, high cholesterol levels, obesity, lack of exercise, diabetes, family history and stress.
• Treatments for CHD: Stents

  • Wire mesh inserted into artery using a balloon to push it into place
  • Opens the coronary artery which allows more blood flow to the heart muscle
  • The heart muscle can then respire aerobically and release the energy needed for heart muscle contraction
• Treatments for CHD: Statins

  Group of medicines that help to lower cholesterol by reducing production of cholesterol inside the liver
• Statins should only be used for people with high cholesterol AND a family history of heart disease
• Valve problems

  Valves withstand lots of pressure and can become leaky or too stiff to open
• Symptoms of valve problems:

  • Breathlessness
  • Fatigue
  • No treatment can result in death
• Mechanical valves->Made out of titanium
• Mechanical valves advantages

  • Made from a hard wearing and strong material
  • Lasts a long time
• Mechanical valves disadvantages

  • Can cause blood clots so medication is needed
• Biological valves are taken from pigs, cows or human donors
• Advantages of biological valves:

  • No need to take medication
• Disadvantages of biological valves:

  • Weaker than mechanical valves
  • Only last 12-15 years
  • People may have objections about using animal parts
• Natural heart pacemakers

  • Heart rate is controlled by group of cells in the right atrium which produce small electrical impulses which spread through the muscular walls of the heart causing them to contract
• If natural pacemakers stop working:

  Too slow->Tiredmess due to lack of oxygen and glucose

  Too fast->Increased blood pressure which causes illness
• Artificial pacemakers:

  • Electrical device implanted into the chest
  • Sends electrical signals to the heart to stimulate heart muscle to beat properly
• Heart transplants are used when the heart completely fails
• Advantages of heart transplants:

  • Save persons life