Download Pulmonary vs. Cellular Respiration

Function of the Lungs
• Primary - to provide a means of gas
exchange between environment and body
• Secondary - maintenance of acid-base
balance and as a resevoir for blood
Ventilation vs. Diffusion
• Ventilation - moving air into and out of the
lungs
– oxygen is moved into the lungs and CO2 is
moved out during ventilation
• Diffusion - random movement of molecules
from area of high concentration to low
concentration
– because O2 concentration is high in the lungs,
and low in the blood, O2 diffuses into the blood
from the lungs (converse for CO2)
Structure
• Conductive zone - area where no gas
exchange occurs, air is simply moved
through (eg. trachea, bronchii)
• Respiratory zone - area where gas exchange
does occur (eg. alveoli)
Major Organs of the Respiratory System
Position of the Pleura and Mediastinum
Pathway of Air to Alveoli
Alveolus at Microscopic Level
Mechanics of Breathing
• Bulk Flow
– movement of air from the environment to the
lungs
– occurs due to pressure differences at end of
system
Cont’d
• Inspiration
– major muscle involved is the diaphragm
– (diaphragm only skeletal muscle in body
considered essential for life)
– intrapulmonary pressure reduced below
atmospheric
– during exercise
• external intercostals, pectoralis minor, scalene,
sternomastoids increase volume of thorax
More
• Expiration
– intrapulmonary pressure exceeds atmospheric
– passive at rest
– during exercise
• rectus abdominus, internal obliques involved
Mechanics of Inspiration and Expiration
• Pulmonary - ventilation (breathing) and gas
exchange in the lungs
• Cellular - O2 utilization and CO2
production in the tissues
Muscles Involved in Respiration