Ecg Cardiology

PULMONARY PHYSIOLOGY

(everything from Watkins/Delaney’s notes is in here, but there’s some extra stuff from the physio for dummies text)

INTRODUCTION

Lung respiratory and conducting zones

Respiratory zone – respiratory bronchioles, alveolar ducts & sacs

Conducting zone – bronchioles, bronchi, trachea

Alveoli have largest cross-sectional area

Bronchioles have smooth muscle & cartilage

23 divisions of branches into ever smaller conduits

Mucous-secreting, ciliated cells line conducting zone airways. Large particles stop at nose, smaller

ones caught in cilia, finest particles (like asbestos) make it into alveoli

Gas exchange can be divided into four functional components:

Ventilation – movement of air into lungs (need pump to generate flow, pipes slow down flow – R)

Perfusion – movement and distribution of blood through pulmonary circulation

Diffusion – movement of O2 and CO2 across air-blood barrier or alveolar-capillary membrane

Control of breathing – process of regulation of gas exchange to meet metabolic needs of moment

Respiratory quotient, RQ = CO2 produced = 200 ml/min. = 0.8 (average)

CO2 consumed

250 ml/min.

Carb RQ = 1, fat RQ = 0.7, protein RQ = 0.8

A = alveolar

a = arterial blood

v = venous blood

Non-respiratory functions of respiratory system:

(upper airway includes nose, paranasal sinuses, naso- and oropharynx, larynx)

1) route for water loss, heat elimination (warms, moistens air so alveoli don’t dry out – oxygen and

carbon dioxide can’t diffuse across a dry membrane)

2) enhances venous return (respiratory pump)

3) helps normalize pH by altering amount of CO2 (H+-producing) exhaled

4) enables speech, singing, other vocalization – larynx – vocal cords act as ‘vibrator’

5) defends against inhaled foreign matter (filters particulates or microbes via mucous coat

propelled towards larynx by ciliary action, cough reflex, sneeze reflex, immunoglobulins – both

locally produced and brought into lung from other sites)

6) removes,...