11.1THE FUNCTION OF RESPIRATION

• Cyctic fibrosis patients can now live into their 40s and beyond

• Can participate in many physical activities

RESPIRATION

• Bring in oxygen, remove CO2 from body cells

• 4 stages

1. Breathing: inspiration and expiration

2. External respiration: gas exchange between lungs and blood

3. Internal respiration: gas exchange between blood and cells

4. Cellular respiration: reactions in cells to release energy

STAGES OF RESPIRATION

Click “play” to watch video

RESPIRATORY SURFACES

• 2 reqiuirements

1. Large enough for quick gas exchange

2. Moist so gas can dissolve

• Different animals evolve different respiratory surfaces and systems

• Common for all is Ventilation: process of drawing/pumping oxygen-containing medium over respiratory surface

TYPES OF RESPIRATORY SURFACES – OUTER SKIN

• Use entire outer skin

• Diffusion of O2 and CO2 in and out of cells from blood

• Must live in moist environments

TYPES OF RESPIRATORY SURFACES – GILLS

• Extensions of folds in the body surface to increase surface area

• Diffusion of O2 and CO2 in and out of cells from blood

• Live in aquatic environments

TYPES OF RESPIRATORY SURFACES – TRACHEAL SYSTEM

• For insects

• Internal system of branching respiratory tracheae (tube)

• Tracheae connects cells directly to environment for gas exchange (blood not required)

TYPES OF RESPIRATORY SURFACES – LUNGS

• For large animals

• Provide more gas exchange

• Contain sacs lined with a moist surface (epithelium)

• Sacs increase surface area

• Blood transports gases to cells by diffusion

AQUATIC GAS EXCHANGE

• Gill users take water into mouth and ventilate over gills

• Dissolved O2 in water diffuse into blood in the gills

• CO2 diffuses out into water

• Counter-current system:

• Water and blood flow in opposite directions

• O2 and CO2 follow diffusion gradients (high low)

TERRESTRIAL GAS EXCHANGE

• Breathing: move air in and out of lungs

• Brain regulates breathing rate and monitors air volume in lungs

• Diaphragm and intercostal muscles :

• Control air pressure inside lungs

• control inhalation and exhalation

• Diaphragm: dome muscle at bottom of thoracic cavity

• Intercostal muscle: rib muscle Click “play” to watch video

AIR PRESSURE IN LUNGS

• Inspiration (inhalation)

• Intercostal muscles and diaphragm contract

• Rib cage moves up and out

• Diaphragm moves down

• Expand thoracic cavity (air-tight)

• Increase volume pressure decrease

• Air from external environment rush into lungs

AIR PRESSURE IN LUNGS

• Expiration (exhalation)

• Opposite of inhalation

• Intercostal muscles and diaphragm relax

• Rib cage moves down and in

• Diaphragm moves up

• Reduce thoracic cavity (air-tight)

• Decrease volume pressure increase

• Forces air out of lungs

play

stop

BREATHING

MEASURING RESPIRATORY VOLUME

Tidal volume:

air volume inhaled and exhaled in a normal breathing movement (body is at rest).

Inspiratory reserve volume:

additional air volume that can be taken into the lungs beyond a regular (tidal) inhalation.

Expiratory reserve volume:

additional air volume that can be forced out of the lungs beyond a regular (tidal) exhalation.

MEASURING RESPIRATORY VOLUME

Vital capacity (total lung volume):

total air volume that can be moved into or out of the lungs.

vital capacity

= tidal volume + inspiratory reserve volume + expiratory reserve volume

Residual volume:

amount of air that remains in the lungs and passageways even after a full exhalation.

SPIROGRAPHS

• Spirometer measures respiratory volume

HOMEWORK

• P.449 #1,3-12,14