(respiration and gas exchange)

• respiration is the chemical reaction that releases energy from glucose in cells, it happens in mitochondria
• aerobic respiration is the chemical reaction in cells that use oxygen to break down nutrient molecules to release energy
• anaerobic respiration is the chemical reaction in cells that releases energy from nutrient molecules without oxygen
• anaerobic respiration releases less energy per molecule of glucose
• oxygen breaks down lactic acid into carbon dioxide and water
• oxygen debt is when the amount of oxygen needed to remove lactic acid, it replaces body's reserves of oxygen
• parts of the resporatory system:

  1. trachea
  2. ribs
  3. intercostal muscles
  4. lungs
  5. bronchi
  6. branchiolies
  7. alveoli
  8. diaphram
• when breathing in, the chest expands, diaphram contracts (moves downwards), rib cage lifts. The volume increases as pressure decreases
• when breathing out, the intercostal muscles relax, rib cage relaxes, diaphram relaxes (lifts). The volume decreases as pressure increases
• ventillation is the process of which air moves in and out of lungs (helps maintain concentration gradient)
• trachea connects throat to bronchi
• bronchioles are air passages in lungs that end with alveoli
• bronchi are air passages that link trachea to bronchioles
• diaphram is a dome shaped muscle separating the thorax from abdomen
• intercostal muscles are between ribs that contract to pull ribs up when breathing in
• ways alveoli are adapted for gas exchange:

  • large surface area (quicker diffusion rate)
  • thin wall (short diffusion distance)
  • moist (helps oxygen dissolve into blood)
  • permeable walls (allow gas to pass through)
• blood consists of plasma, red blood cells, white blood cells (lymphocyte + phagocyte), platelets
• red blood cells carry oxygen throughout the body and contain haemoglobin. They have a bioconcave shape to increase surface area for oxygen to bind to
• white blood cells protect body against pathogens through phagocytosis and antibody protection. 70% are phagocytes, 30% are lymphocytes
• plasma transports glucose, CO2, amino acids, lactic acid throughout the body. 90% is water
• platelets are fragments of cells, clots wounds
• ways body protects against pathogens:

  • respiratory sytem (trachea and bronchi produce mucus to catch pathogens)
  • eyes (tears have protective enzymes)
  • ears (mucus prevents pathogen entering)
  • skin (antimicrobial secretions)
  • stomach/digestive system (HCL acid kills pathogens)
• lymphocytes attach antigens to antibodies on pathogens. Pathogens stick together (limit movement), burst open, or have phagocytes engulf them. Antigen shapes are specific to antibodies
• phagocyte finds pathogens and attaches onto it, engulfs and digests it, residue is removed
• pulminary artery (right) is from heart to lung
• vena cava (right) is from body to heart
• ventricle is the lower chamber of the heart, atrium is the top chamber
• aorta (left) is from the heart to body
• pulminary vein (left) is from the lung to heart
• process of heart beating:

  1. blood from body goes through vena cava into atrium (right) + blood from lung goes through pulminary vein into atrium (left)
  2. atria contract to push blood to ventricles
  3. valves close to stop blood from re-entering heart
  4. blood goes from right ventricle through pulminary artery to lung + blood goes from left ventricle through aorta to body
• left ventricle is thicker than right ventricle because it needs more muscles and thicker walls to pump higher blood pressure to body
• ventricles are thicker that atriums because it needs thicker walls and muscles to pump a higher blood pressure
• pulmonary = lungs

  cardiac = heart

  hepatic = liver

  renal = kidney
• pulmonary artery = heart to lung

  pulmonary vein = lung to heart
• hepatic artery = heart to liver

  hepatic vein = liver to heart

  hepatic portal vein = intestines to liver to heart
• renal artery = heart to kidney

  renal vein = kidney to heart
• structure of arteries

  • thicker walls
  • narrower lumen
  • more muscle
  • no valves
  • more elasticity
• structure of veins:

  • wider lumen
  • thinner wall
  • less elasticity
  • less muscles
  • valves
• structure of capillaries:

  • very small lumen
  • thin 1 cell thick wall
• after excercise, more enrgy and oxygen is needed, so respiration + heart + breathing rate will increase to replace lactic acid