Respiration

• Respiration is a chemical reaction that is carried out in all living organisms
• Structure of the thorax

  1. Ribs

  Bone cage that protects the internal organs such as lungs 

  1. Intercostal muscle

  Muscles between the ribs which control their movement during exhalation and inhalation.

  1. Diaphragm

  A Sheet of connective tissue and muscle that helps change volume of throax, allowing inhalation and exhalation (P1V1 = P2V2)

  1. Trachea 

  Windpipe that connects the mouth and nose to the lungs 

  1. Bronchi

  2 large tubes branching off trachea.

  1. Bronchioles

  Bronchi split into smaller tubers, connected to alveolis.

  1. Alveolis 

  Tiny air sacs where gas exchange takes place
• Alveoli + adaptations

  1. Large surface area to volume ratios
  2. Thin, single layer of cells 
  3. Layer of moisture - allow easier gas diffusion 
  4. High conc. of O2 in alveolis - big concentration gradient faster diffusion
• Tar

  Tar is a carcinogen. Tar causes an increase of production in mucus, destroying the cillia, and mucus builds up, blocking small bronchioles and leading to infections.

  The infections lead to emphysema, meaning the alveoli becomes less elastic and can’t stretch, so many burst. This means there’s less surface area for gas exchange.
• Carbon monoxide binds irreversibly to haemoglobin, which reduces the capacity of blood to carry oxygen. Hence there is more strain on the breathing system, as breathing frequency and depth need to increase in order to get the same amount of oxygen into the blood. This increases the risk of coronary heart disease and strokes
• How our immune system responds to infection

  1. Pathogens are in blood stream and they multiply

  2. They cause symptoms for us by releasing toxins and infection of body cells

  3. Phagocytes that encounter these pathogens starts to engulf and digest it

  4. Lymphocytes that encounter these pathogens start to produce antibodies to the pathogen's specific antigen

  5. Lymphocytes begin to clone itself to produce more antibodies

  6. Antibodies cause agglutination to antigens which slows the pathogens down

  7. Antibodies release chemicals that signal to pathogens of the present of pathogens

  8. Antibodies and memory cells are circulating in the blood system
• Vaccines

  1. A harmless version of the pathogen is injected into our bloodstream
  2. Phagocytes encounter these pathogens and starts to engulf and digest it
  3. Lymphocytes that encounter these pathogens begin to produce antibodies that are specific to the pathogen’s antigen.
  4. Lymphocytes begin to clone themselves to make more antibodies
  5. These antibodies cause agglutination too slow pathogens down. They also release chemicals to phagocytes of the presence of the pathogens.
  6. These antibodies are memory cells circulating around the blood system. 
• Pathway of blood

  1. Deoxygenated blood from the body flows through vena cava

  2. From the right atrium, through the atrioventricular valve then to the right ventricle

  3. The right ventricle contracts and blood is pushed through semilunar valve into the pulmonary artery

  4. Blood travels to the lungs and moves through the capillaries to the alveoli, where gas exchange takes place

  5. Oxygenated blood returns through the pulmonary vein to the left atrium

  6. Through the atrioventricular valve, blood flows to the left ventricle

  7. Ventricle contracts and the blood is forced through the semilunar valve, and out the aorta, providing oxygenated blood to the rest of the body