- video. passage of air from outside the body to the lungs and gas exchange
TRANSCRIPT
Passage of air from outside the body to the lungs and gas exchange
3 Main Functions:
• supply oxygen to the blood
• remove carbon dioxide from the blood
• regulate blood pH
Breathing vs Respiration
-getting air to the lungs 3 Types: (movement of gases)
1. External O2/CO2 exchange in lungs
2. Internal gas exchange at the tissue level
3. Cellular utilizing O2 for energy
Conductive Zone vs Respiratory Zone
Nasal cavity
Mouth
Pharynx
Larynx
Trachea
Bronchii
• warm
• humidfy
• filter
-hairs
-mucous
Bronchioles
Terminal bronchiole
Respiratory bronchiole
Alveolar sac
• gas exchange
• each sac covered by network of capillaries short diffusion
- grape like structure
-HUGE surface area
?
Pulmonary artery
Pulmonary vein
-video
“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
So how do we breath?
Diaphragm contracts (moves down)
Chest increases in size 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?
Graphically????
What controls ventilation?
CNS medulla oblongata (contraction/relaxation of muscles)
-O2 vs CO2 needs
Bicarbonate (HCO3)
-blood pH (buffer)
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
Now what happens with the air in the lungs?
Gas Exchange (Alveoli)
• Respiration
• Lungs O2 blood CO2 Lungs
DIFFUSION!!
* Read pages 123-124 *
• Describe partial pressures
• Explain the 3 factors that contribute to gas exchange
•Diffusion pathway
•Barrier thickness
•Surface area
-video
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
Carbon Dioxide Transport
Read page 125: Carbon Dioxide Transport and Ventilation and the Regulation of Blood pH
Make your own brief notes on:
a) The 3 ways in which CO2 is transported in the blood
b) The role pH plays in human ventilation