“movement of air from outside the body to the lungs”

Diaphragm is the principle muscle in controlling breathing upon stimulation, will contract

Air outside Air inside

PRESSURE CHANGES

High pressure Low pressure

Pleural membrane covers lungs and allows smoother movement

So how do we breath?

Diaphragm contracts (moves down)

Chest increases in size (intercostal muscles) air space increases

Decrease in pressure in the lungs

.: Pressure outside body > inside body

Air rushes in

INHALATION (active process)

EXHALATION (passive/active)

Diaphragm relaxes

Chest decreases in size air space decreases

Increase in pressure in the lungs

.: Pressure outside body < inside body

Air rushes out Quiet breathing

Forced breathing

Ventilation (VE )

“The volume of air that is moved in 1 minute.”

VE (L/min)= VT (L) x f (breaths/min)

Air in and out

Tidal Volume

• volume of air in each breath

• rest = 0.5 L/min

max = 3-4 L/min

Respiratory frequency

• number of breaths per minute

• rest = 12 breaths/min

max = 30-40 breaths/min

Ventilation at maximum?

Using your textbook (page 443) label, name and define the 6 short forms above

Depends on: sex, body type, and lifestyle

So we’ve got the air to the lungs. . .

Lung Volumes

Static

vs

Dynamic

-volumes determined by structure of lung

-volumes dependent on movement of air

TLC = VC + RV

Total Lung Capacity

• max air lungs hold

Vital Capacity

• max air exhaled following max inhale

Residual Volume

• remaining air in lungs after max exhale

VO2: rate at which oxygen is used by the body

-measured in mL/kg/min

mVO2 VO2max

-measure of efficiency of the respiratory system

How do we calculate?

mVO2 = 15 HRmax

HRmin

220-age

O2 Transport• 2% dissolved in plasma

• VAST majority binds to hemoglobin (1.34 ml of O2 per molecule)

• OXYHAEMOGLOBIN DISSOCIATION CURVE

-Percent saturation of hemoglobin (SbO2%)

-Pressure of oxygen in the blood (PO2)

What does this graph illustrate?

The lower the PO2, the less O2 will bind to hemoglobin

Your turn,

In your own words discuss what effect ALTITUDE has on respiration. Read page 449 in your textbook to help with your understanding.