Respiration Air Ventilation Gas exchange (alveoli) Gas transport (blood) Tissues Uptake O 2 for energy Download CO 2

Consumption of O 2 and production of CO 2 Determination by spirometry Respiratory quotients for carbohydrates and fats RQ = CO 2 produced O 2 consumed 200 ml / min 250 ml / min = 0.8 = Sugar + O 2 CO 2 + H 2 O energy

Function of Upper Airways Warm Humidify Filter / clean /immune defense Air Extensive 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 contraction Chest 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

1 mmHg = 13.6 mm H 2 O 1 mmHg = 1.36 cm H 2 O

760 mmHg

Normal airflow achieved Lungs inspiration  1 mmHg expiration + 1 mmHg Max inspir effort  50 mmHg Max expir effort 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

Summary Respiration ventilation perfusion gas exchange gas transport cellular respiration CO 2 production,O 2 consumption–respir quotient Functions of upper airways Mechanism of inspiration & expiration Lung volumes