RESPIRATION  Up to this point, respiration referred to cellular respiration, the life function that releases energy from glucose for cell’s activities.

The RESPIRATORY SYSTEM Includes organs and tissues that bring in the oxygen for aerobic respiration Also removes the carbon dioxide produced from cellular respiration

RESPIRATORY SYSTEM includes  Nose, which warms, filters, and moistens air  The air flows through the pharynx, past the epiglottis, which is a flap to prevent choking

AIR  Moves through the trachea and bronchi which also contain ciliated cells to clean the air  Cilia beat constantly to move “junk” upwards

TRACHEA  (aka windpipe) and bronchi are held open by cartilage rings  The bronchi branch into bronchioles

ALVEOLI  The air sacs, called alveoli, where actual diffusion occurs, are at the end of the bronchioles  These alveoli are thin-walled “bubbles” surrounded by capillaries

Alveoli  Expand and contract when we breathe  Alveoli create a large surface area for gas exchange  Image a box that measures 1 meter on each side. The total surface area inside the box is 6 square meters. Now take same amount of space (1 cubic meter) and divide it into 100,000 little cubes that are 1 centimeter on each side. The surface are on the inside of all those little cubes is 600 square meters.

Gas Exchange  Happens at the alveoli by diffusion.  Carbon dioxide from the capillaries diffuses into alveoli to be exhaled.  Oxygen from the alveoli diffuses into the capillaries to be transported to cells.  Gases move from high to low concentration-no energy is used by the cells for this process.

Mechanics of Breathing  The diaphragm is a muscle across our body underneath our lungs  When it contracts, it expands the chest cavity, causing air to rush in (‘member high to low pressure in earth science?)

Exhalation  Is actually a form of excretion (eeeyuu), ridding our body of the wastes of metabolism: carbon dioxide, moisture, excess heat

DISORDERS  Bronchitis is an inflammation (“itis”) of the bronchi  Emphysema collapses all those little alveoli, decreasing surface area for gas exchange