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Respiration
Air
Ventilation
Gas exchange (alveoli)
Gas transport (blood)
Tissues
• Uptake O2
for energy
• Download CO2
Consumption of O2 and production of CO2
Determination by spirometry
Respiratory quotients for carbohydrates and fats
RQ =CO2 produced
O2 consumed
200 ml / min
250 ml / min= 0.8 =
Sugar + O2 CO2 + H2O
energy
Function of Upper Airways
• Warm
• Humidify
• Filter / clean
/immune defense
AirExtensive vascular mucous membrane
• Maintain / provide airway
• Special functions: smell
taste
voice
Pharnyx and Larnyx
1. Maintenance of airway
2. Pharnyx immune defense
Airway maintenance:
1. Intrinsic tone of pharngeal muscles, tongue
2. Relfexes: swallowing reflex
cough reflex
Airway maintenance is compromised:
• muscle floppy
• reflexes
1. Unconscious
face down and to side
gravity assists
2. Alcohol
3. Opiates, barbiturates, anaesthetic gases, artificial airways
4. Sleep
Fig. shows envelopment of the alveoli by pulmonary capillaries.
From periphery via R side of heart
To periphery via L side of heart
Inspiration is active process: muscle contractionChest volume
Lung vol
Air pressure
Air in through mouth and nose
Expiration (quiet) involves controlled muscle relaxation
Chest volume
Lung vol
Air pressure
Air out through mouth and nose
Normal airflow achieved
Lungs
• inspiration 1 mmHg
• expiration + 1 mmHg
• Max inspir effort
50 mmHg
• Max expir effort
+ 100 mmHg
Mouth
• 0 mmHg
Muscles of Respiration
Quiet breathing:
• Inspiration: diaphragm — phrenic N. C3,4,5
• Expiration: controlled relaxation, diaphragm
Heavy breathing:
• Accessory muscles
•Inspiration: external intercostals, neck muscles
•Expiration: abdominal muscles, internal intercostals