Respiratory system

• What is the Larynx?

  connects the back of the nose and the trachea, forming an air passage to the lungs
• What is the trachea, bronchi and bronchioles?

  • Trachea, aka the windpipe, starts at the back of the throat (pharynx) and divides into two bronchi
  • each bronchi leads into one of the lungs where they continue to divide to form smaller bronchioles
  • The trachea and bronchi are tubes that have rings of cartilage along their length to stop them collapsing so that an open passage for air is maintained
  • rings are 'c' shaped in the trachea with the gap at the back to allow food to travel down the oesophagus, that stretches as food passes down
• What is the alveoli?


  At the end of the tiniest bromchioles are the microscopic alveoli, sacs found in clusters at the end of the bronchioles. One sac is called a alveolus. Each alveolus is surrounded by a capillary network where oxygen and carbon dioxide are exchanged through the alveoalar membrane. There are about 300 million alveoli in your lungs.
• What is the diaphragm?

  This is a muscle anchored to the lower ribs that seperates the chest from the abdomen
• What are the intercostal muscles?

  muscles found between the ribs
• What are the pleural membranes?

  Cover the outside of the lungs and line the inside of the chest wall
• What are the roles of pleural membranes?

  • Pleural membranes consist of two layers of thin membrane that are moist and slippery, having a thin film of liquid between the two layers lubricates the surface so that the two pleural layers will slide over each other, allowing the lungs to move easily with the chest cavity
  • This means that they move with the chest wall as breathing occurs
• What is the role of the diaphragm and intercostal muscles?

  • Function of respiration is to deliver oxygen into the body by inspiration and remove the waste carbon dioxide gas by expiration
  • inspiration, intercostal muscles pull the ribcage up and out and the diaphragm flattens inwards. The result of these movements is an increase in volume and a decrease in pressure, forcing air into the lungs so that they inflate
  • expiration, the diaphragm lifts back into a dome shape and the intercostal muscles pull the ribcage in and down. these movements force carbon dioxide out the lungs and they deflate
• What is gaseous exchange?

  A process that involves the exchange of oxygen and carbon dioxide between capillaries and alveoli
• What is the role and structure of alveoli walls in gaseous exchange?

  • exchange of oxygen and carbon dioxide takes place in the alveoli, walls of alveoli are one cell thick, each alveoli is surrounded by capillaries where gases are exchanged
  • structure of alveoli are like bunches of grapes, increasing surface area allowing maximum crossover/diffusion, of the gases back and forth making the process efficient
  • Diffusion allows oxygen to leave alveoli into capillaries and into the bloodstream,carbon dioxide will move out capillaries, into alveoli and to the lungs to be exhaled.
• What are diffusion gradients?

  Diffusion, movement of molecules from an area of high concentration to low concentration. This is the case with gases and for particles dissolved in solutions. Particles diffuse down a concentraction gradient, from high concentration to an area of low concentration.

  • Capillaries have a lower concentration of oxygen than the alveoli
  • Ths results in diffusion of oxygen - from an area of high concentration (alveoli) to an area of lower concentration in the red blood cells (in capillaries)
• What is the role of erythrocytes and plasma in the respiratory process?

  Erthythrocytes transport oxygen via haemoglobin to the body tissues, and plasma transports carbon dioxide that is produced by respiration in the lungs.

  1. Inspiration
  2. Exchange of gases from lungs to blood
  3. Transport of oxygen and carbon dioxide in the blood
  4. Exchanges of gases from blood to tissues
  5. Metabolism
  6. Expiration
• What is cellular respiration?

  ATP is a high-energy molecule found in every cell, its job is to store and supply the cell with the energy it needs. It is sometimes called the energy currency of the body.

  Cellular respiration is a complex set of chemical reactions and processes that take place in the mitochondria to convert biochemical energy from nutrients into ATP and then to release waste products

  2 types of respiration in cells that provide energy:

  • Aerobic: uses oxygen
  • Anerobic: doesnt use oxygen
• What is aerobic respiration?

  • Oxygen and glucose are required for aerobic respiration to take place. It produces waste carbon dioxide and water as well as providing energy.
  • Glucose + oxygen $\rightarrow$ Carbon dioxide + water (32 ATP)
  • A sugar called glucose, from our food, is broken down into water and carbon dioxide, and the energy that was holding the glucose molecule together is released
• What is anaerobic respiration?

  without oxygen, provides less energy

  glucose → pyruvate → lactate (2 ATP)

  • Glycolysis in cell cytoplasm, breaks down glucose + forms pyruvate with production of 2 ATP.
  • Pyruvate used in anarobic if no oxygen is available, in aerobic by a cycle of chemical reactions that yeild more usable energy for a cell
• What happens during anaerobic respiration p2?

  pyruvic acid gives energy to cells through the Krebbs cycle when oxygen is there, when oxygen lacks, it ferments to produce lactic acid that is then oxidised into carbon dioxide and water to prevent build up. If oxygen doesnt become available cells die because lactate is toxic.

  • Anaerobic is likely to occur when oxygen is in short supply, such as when exercising because muscles need energy.