B5d - Respiratory Systems

B5d - Respiratory Systems

1. Types of Respiratory Systems

   • Because of their respiratory systems, amphibians can only live in moist habitats
   • Amphibians have simple lungs, but use their skin to get oxygen. Because the skin is so permeable they are susceptable to water loss and so live in moist conditions
   • Fish get their oxygen from water being forced over filaments, so only work in water.

2. Gaseous exchange

   • In humans, breathing in depends on the contraction of the intercostal muscles and the muscles in the diaghram
   • The Total Lung Capacity
     • Tidal Air - the amount of air normally breathed in and out while at rest
     • Vital Capcity - the max amount of air which can be exchanged
     • Residual Air - the amount of air which cannot be forced out of the lungs
   • Excghange of gases happens by diffusion between the alveoli and th air in the air sacs.
     • Diffusion occurs because the oxygen concentration in the air is higher than in the deoxygenated blood capillaries
   • The exchange surfaces are adapted for efficient gas exhange - large surface area, good blood supply and permeable, moist and one cell thick
   • Spirometer readings measure different lung capacities and the rate of airflow

3. Respiratory Diseases

   • Asbestosis is caused by inhaling asbestos fibres. They can cause inflammation and scarring of lung tissue, reducing gas exchange.
   • The risk of Lung Cancer is increased by lifestyle factors eg smooking. Lung cells grow rapidly, reducing the surface area available for gas exchange
   • In Cystic Fibrosis there is too much mucus produced in the bronchioles causing breathing difficulties
   • During an Ashtma attack the LINING of airways becomes inflamed, mucus and fluid build up in airways and the muscles around the bronchioles contract, narrowing the airways
     • Symptoms are wheezing, tight chest and difficulty in breathing. Inhalers can be used to relieve symptoms

Images and files in the map