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Respiration Air Ventilati on Gas exchange (alveoli) Gas transport (blood) Tissues • Uptake O 2 for • Download CO 2

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

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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

1 mmHg = 13.6 mm H2O

1 mmHg = 1.36 cm H2O

760 mmHg

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

Summary

• Respiration

ventilation

perfusion

gas exchange

gas transport

cellular respiration

• CO2production,O2consumption–respir quotient

• Functions of upper airways

• Mechanism of inspiration & expiration

• Lung volumes