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