Human Anatomy and Physiology Physiology of air breathing The lungs.

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Human Anatomy and Physiology Physiology of air breathing The lungs

Transcript of Human Anatomy and Physiology Physiology of air breathing The lungs.

Page 1: Human Anatomy and Physiology Physiology of air breathing The lungs.

Human Anatomy and Physiology

Physiology of air breathing The lungs

Page 2: Human Anatomy and Physiology Physiology of air breathing The lungs.

Respiration

Oxygen utilization varies with activity Rest: 200 ml/min. Exercise: 6,000 ml/min.

Importance Breathing increases due to metabolic

demands Regulated by pH of ECF

Page 3: Human Anatomy and Physiology Physiology of air breathing The lungs.

Organization

Conducting zone Trachea, 1° - 3° bronchi

Respiratory zone Bronchioles, alveolar ducts

alveoli

Trachea1°

brochioles

Alveolor ducts

alveoli

Page 4: Human Anatomy and Physiology Physiology of air breathing The lungs.

Functions of pathway

Conducting zone Warm, cleanse and humidify air Phonation (vocal cords) Regulation of air flow (dilation/constriction)

Page 5: Human Anatomy and Physiology Physiology of air breathing The lungs.

Functions of pathway Respiratory zone

Gas exchange

Page 6: Human Anatomy and Physiology Physiology of air breathing The lungs.

Functions of pathway Respiratory zone

Cell type I (gas exchange) Cell type II (surfactant)

Page 7: Human Anatomy and Physiology Physiology of air breathing The lungs.

Gas Exchange Gases must penetrate 3 membranes

1.

2.

3.

Page 8: Human Anatomy and Physiology Physiology of air breathing The lungs.

Diffusion distances Shorter is better

Animal Diffusion distance (µm)

Toad

Birds

pigeon

swallow

shrike

Mammals

rat

human

shrew

1.3 - 3.0

0.1 - 1.4

0.09

0.17

0.13 - 0.26

0.36 - 2.5

0.27

Page 9: Human Anatomy and Physiology Physiology of air breathing The lungs.

Lung ventilation Closed compartment

Head, diaphragm, sternum, ribs and intercostal muscles

Pleura Parietal (chest) Visceral (lungs) Pleural fluid

Page 10: Human Anatomy and Physiology Physiology of air breathing The lungs.

Ventilation steps

Exchange of air between atm. and alveoli Ventilation, bulk flow

Exchange of O2 and CO2 between alveoli and lung capillaries Diffusion

Transport of gases by blood Bulk flow

Exchange of gases between blood and tissues Diffusion

Page 11: Human Anatomy and Physiology Physiology of air breathing The lungs.

Ventilation

Inspiration Expiration

Atmospheric Pressure760 mm Hg

Alveolar Pressure<760

Alveolar Pressure>760

Page 12: Human Anatomy and Physiology Physiology of air breathing The lungs.

Ventilation

What pressure changes? Ans: alveolar pressure Bulk flow: F = K (∆P) How does pressure change?

Page 13: Human Anatomy and Physiology Physiology of air breathing The lungs.

Ventilation Cavities

Pleural, pulmonary Intrapleural pressure. Why have it?

Tendency of lung recoil Surface tension of alveolar fluid Opposed by chest wall elasticity

Intrapulmonary pressure Balloon within a balloon

Page 14: Human Anatomy and Physiology Physiology of air breathing The lungs.

Ventilation

ExpirationInspiration

Page 15: Human Anatomy and Physiology Physiology of air breathing The lungs.

Ventilation

Page 16: Human Anatomy and Physiology Physiology of air breathing The lungs.

Air flow

Flow (F) = ∆P/R ∆P: change in pressure between

atmosphere and alveoli R: resistance of airways

Page 17: Human Anatomy and Physiology Physiology of air breathing The lungs.

Air flow

∆P: altered by contraction of inspiratory and expiratory muscles

Resistance Inversely proportional to 4th power of radius

R =1

r4 A B

R =1

1

R =1

81

Page 18: Human Anatomy and Physiology Physiology of air breathing The lungs.

Air flow Lung compliance

V = change in volume P = change in pressure

V

P

Athletes have a high lung compliance

Page 19: Human Anatomy and Physiology Physiology of air breathing The lungs.

Lung volumes Respirometer

Page 20: Human Anatomy and Physiology Physiology of air breathing The lungs.

Lung volumes

Page 21: Human Anatomy and Physiology Physiology of air breathing The lungs.

Dead space Anatomical dead space Alveolar dead space (inspired dead space)

Total dead space