Ch 12 Pt2 Flashcards
External Respiration
Exchange of gases at alveoli (lung level)
Internal Respiration
Exchange of gases at muscular level
Cellular Respiration
Utilization of O2 by the muscles as they use and uptake O2, then secrete CO2
Movement of air depends on 2 things:
Pressure gradient and Resistance
High pressure to low pressure or high concentration to low concentration is:
Pressure Gradient
Tissue friction or airway resistance is:
Resistance
Tissue friction: as lungs move (20%)
Airway friction: between gas and walls of airway (80%)
Boyles Law
The pressure of a gas is inversely related to its volume
-how the lungs function/ how we get air in and out
low pressure= high volume,
High pressure= low volume
Inspiration is…
Always an active process
-muscles have to contract in order to breath in
Main/ Primary inspiration muscles are: (2)
Diaphragm: dome shaped muscle directly below the lungs and directly above visceral organs
External Intercostals: muscles running alongside ribcage
How does the diaphragm and external intercostals cause inhalation
Diaphragm: contracts upon neural stimulation -flattens and moves down -elongates the chest cavity
External Intercostals: elevate the rib cage and expand chest cavity further
-laterally (side to side) and anterposteriorly (front and back)
Pleura:
Thin, double layered membrane that lines the chest cavity and external lung surfaces
-changes in chest cavity are transferred to lungs because of pleura
2 types of Pleura:
Visceral (pulmonary) and
Parietal (chest) pleura: lines the region of the thoracic cavity between the lungs
-adherence of lungs to chest cavity
When’s lungs expand:
Volume Increases, meaning pressure decreases
-due to pressure gradient
Intrapulmonary pressure is what related to atmospheric pressure
Less than atmospheric pressure, meaning air flows into the lungs due to pressure gradient
During heavy forced breathing, inspiration is assisted by what other muscles (3)
Pectoralis major, scalene, sternocleidomastoid, etc
Expiration is:
A passive process (at rest)
The relaxation of the inspiratory muscles (external intercostals., diaphragm)
-elastic recoil of the lungs
In expiration, Intrathoracic (intrapulmonary) pressure is greater than:
The atmospheric pressure
-air flows out
During forced breathe, expiration is:
Active -uses:
Internal Intercostals: actively pull ribs down (faster than recoil of lungs -air forced out faster)
Abdominal muscles- contract and increase intra-abdominal pressure -force the visceral up against the diaphragm and move it back to domed position
Air flow due to pressure gradients:
Inspiration
Increase volume, decrease pressure
Air= 760mmHg, Lunhs= 758mmHg
-air flows from high to low, flows into lungs
Air flow due to pressure gradients:
Expiration
Decrease in volume and increase in pressure
Air: 760mmHg, Lungs 762mmHg
-air flows out -high to low pressure
Respiratory Pump
Changes in intra-thoracic and intra-abdominal pressure assist in venous return
-pressure increase, vena cava transports blood back to heart
-pressure decrease, veins return to original size
Respiratory Circulation 2 systems:
Pulmonary CIrculation -pulmonary artery and vein, capillaries
-services external respiration
Respiratory/ bronchiole Circulation
-services internal respiration
Pulmonary Circulation
Pulmonary artery -right ventricle to lungs
-deoxygenated blood
Pulmonary vein -lung to left atria
-oxygenated blood
Pressure is higher in artery than vein
Bronchial Circulation
Small arteries that originate from aorta, travel through the lungs, return as veins that empty into pulmonary veins
Deoxygenated blood carrying veins empty into oxygenated space
