1. Structure and Function
The Pulmonary System
Structure and Function

2. Lungs
Lung tissue weighs 1 kg and covers half a tennis court ( square feet)
Lung tissue is times larger than the body’s external surface
Hold 4-6 liters of air.
Unattached to ribs; suspended inside the pleural sacs.

3. Function Ventilation. Breathing (air in and air out) Respiration.
Conduction.
Movement of air through the pulmonary system
Respiration.
Gas exchange (O2 and CO2)

4. Conduction Zone (humidify, filter)
Nasal cavity and Pharynx
Nose moistens, warms, and filters air; mouth does not.
Larynx - voice box
Epiglottis
Valsalva maneuver

5. Conduction Zone (humidify, filter)
Trachea
conducting tube (transports air)
Bronchi
Branches
contains muscle, serves to dilate and constrict
Anatomic dead space

7. Respiration Bronchioles Alveolar sacs (300 million) further branching
Each alveoli is surrounded by a network or covering of capillaries.
Almost forms a “sheet” of blood.
At rest, a single blood cell passes by 2 or 3 alveoli in about 0.5 to 1.0 seconds

10. Respiration (gas exchange)
Occurs through thin walls (0.3 micrometers)
Diffusion of gases from high to low concentration.

11. Types of Respiration Pulmonary (external)
Transfer of O2 and CO2 at the lungs.
250 mL of oxygen is exchanged per minute at rest
200 mL of CO2 is exchanged per minute at rest
These numbers can increase up to 25 times during heavy exercise
Cellular (internal) respiration - transfer of O2 and CO2 in the tissues.

12. Mechanics of Breathing

13. Pleura Pair of membranes (inner and outer) surrounding the lungs
Fluid in between two sacs provides the only attachment of the lungs to the thorasic cavity (ribs).

14. Pleura

15. Pleura

16. Pneumothroax

17. Pressure
Inspiration
Air moves into the lungs due to a lower pressure inside the lungs
Expansion of the rib cage and the lowering of the diaphragm increase the volume
As the volume gets larger, the pressure becomes lower.
                                                             

18. Pressure
Expiration
Air moves out of the lungs due to a higher pressure inside the lungs
Constriction of the rib cage and the raising of the diaphragm decrease the volume
As the volume gets smaller, the pressure becomes higher.

22. Muscles of Ventilation
Inspiration
Rest
diaphragm and E.IC muscles
Exercise
pectorals, scalenes, SCM
Expiration
no muscles
abs, I.IC. muscles)

24. Lungs and Exercise At rest, the blood is 97-98% saturated with oxygen
Exercise, the blood remains 97-98% saturated
Healthy lungs do not limit a person’s ability to exercise
However, respiratory muscles need to be trained like any other skeletal muscle