Biology

• Red blood cell


  Contains hemoglobin to transport oxygen in the blood
• Hemoglobin


  A quaternary structure protein with four polypeptide chains, each containing a heme group with iron that binds oxygen
• There are different types of hemoglobin found in different organisms and tissues
• Affinity


  The ability of hemoglobin to attract and bind oxygen
• Saturation


  The maximum amount of oxygen that hemoglobin can bind
• Loading/Association


  When oxygen is binding to hemoglobin
• Unloading/Dissociation


  When oxygen is detaching or unbinding from hemoglobin
• Oxyhemoglobin dissociation curve


  • Sigmoid (S-shaped) curve
  • Demonstrates how hemoglobin's affinity for oxygen changes at different partial pressures of oxygen
• High partial pressure of oxygen

  Hemoglobin is almost 100% saturated with oxygen
• Low partial pressure of oxygen

  Hemoglobin is only about 50% saturated with oxygen
• Cooperative binding


  The first oxygens bind with difficulty, but then make it much easier for subsequent oxygens to bind
• Bohr effect


  The decrease in hemoglobin's affinity for oxygen when there is a high concentration of carbon dioxide, which makes the blood more acidic
• High carbon dioxide concentration

  Oxyhemoglobin dissociation curve shifts to the right, indicating decreased affinity for oxygen
• Low carbon dioxide concentration

  Oxyhemoglobin dissociation curve shifts to the left, indicating increased affinity for oxygen
• Hemoglobin types in different animals

  • Fetal hemoglobin (higher affinity)
  • Llama hemoglobin (higher affinity at low oxygen pressures)
  • Dove hemoglobin (lower affinity for faster unloading)
  • Earthworm hemoglobin (higher affinity at low oxygen pressures)
• Different hemoglobin types allow organisms to adapt to their environments by adjusting oxygen binding and release
• The cardiac cycle is looking at the pressure and the volume changes within the heart how that controls the opening and closing of the valves and how the valves make sure the blood flows in One Direction
• Cardiac cycle stages


  1. Diol

  2. Atrial syy

  3. Ventricular syy
• During diol, the atrial and ventricular muscles are relaxed, and blood will flow into the atria as the pressure rises
• Atrial syy


  Atria contract, decreasing their volume and increasing pressure to force blood into the ventricles
• Ventricular syy


  Ventricles contract, decreasing their volume and increasing pressure to force blood out of the heart
• Atrio-ventricular valves


  Open when pressure is higher behind (in atria) than in front (in ventricles)
• Semi-lunar valves


  Open when pressure is higher behind (in ventricles) than in front (in arteries)
• Atrial syy


  Increases atrial pressure, opens atrio-ventricular valves
• Ventricular syy


  Increases ventricular pressure, closes atrio-ventricular valves, opens semi-lunar valves
• Diol


  Decreases pressure in both atria and ventricles, allows blood to flow into the heart
• Cardiac output


  Volume of blood leaving a ventricle per minute, calculated as heart rate x stroke volume
• The valves ensure unidirectional blood flow through the heart
• Interpreting pressure change graphs requires understanding when valves open and close based on pressure differences
• A common exam question is to calculate heart rate from the duration of one cardiac cycle shown on a graph
• Ventilation


  The flow of air in and out of the alveoli
• Ventilation


  1. Inspiration

  2. Expiration
• Muscles involved in ventilation

  • Intercostal muscles
  • Diaphragm
• Inspiration


  1. External intercostal muscles contract

  2. Internal intercostal muscles relax

  3. Ribs raise upwards

  4. Diaphragm contracts and flattens

  5. Volume inside thorax increases, pressure decreases

  6. Pressure gradient causes air to be forced into lungs
• Expiration


  1. Internal intercostal muscles contract

  2. External intercostal muscles relax

  3. Rib cage lowers

  4. Diaphragm relaxes and raises upwards

  5. Volume inside thorax decreases, pressure increases

  6. Increased pressure forces air out of lungs
• Tissue fluid


  A liquid containing dissolved oxygen and nutrients which serves as a means of supplying the tissues with the essential solutes in exchange for waste products such as carbon dioxide
• Hydrostatic pressure


  Pressure created when blood is pumped along the arteries, into arterioles and then capillaries, forcing blood fluid out of the capillaries
• Components of tissue fluid

  • Dissolved nutrients such as amino acids
  • Fatty acids
  • Ions in solution
  • Glucose
  • Oxygen
• Only substances which are small enough to escape through the gap in a capillary are components of the tissue fluid
• Tissue fluid and blood contain solutes

  They have a negative water potential