RESPIRATION

The exchange of gases between aliving organism and its environment

FUNCTIONS OF THERESPIRATORY SYSTEM

Intake of O2 Remove CO2

Maintains homeostasis: pH, CO2 acid-base balance of blood

Endocrine functions

Respiratory system

Surface exposed to the environment is large 70 sq.m

Movement of air:10000 liters a dayHalf liter each breathIncreases during work/exercise60 liters per minute

FUELO2 CO2

H2O

METABOLISMMETABOLISM =SUM OF CHEMICAL ANDPHYSICAL PROCESSESWHICH MAINTAIN LIFE

VENTILATIONVENTILATION

O2CO2

UTILIZATIONUTILIZATION

TRANSPORTATIONTRANSPORTATION

DIFFUSIONDIFFUSION

PHASES OFPHASES OFRESPIRATIONRESPIRATION

Respiratory system

Neuro-regulatory mechanisms“The Pump” Musculo-skeletal :

rib cage, respiratory muscles, pleura

Conducting Airways : nose, pharynx, larynx, trachea, bronchi

Gas exchange surface: alveoli

Defense mechanismsHeart-lung interactions

RESPIRATORY MUSCLES

TRACHEA

BRONCHI

BRONCHIOLES

ALVEOLAR DUCTS

ALVEOLI(AIR SACS)

NASAL PASSAGE

TRACHEAITIS

BRONCHITIS

BRONCHIOLIOLITIS

ALVEOLAR DUCTS

ALVEOLITIS(AIR SACS)

RHINITIS

TRACHEAMAIN BRONCHI

PULMONARYVEINSPULM

ARTERIES

ALVEOLUS

BLOODCAPILLARY

O2

CO2

Capillary

Alveolus

RBC

BLOOD

Respiratory system

Neuro-regulatory mechanisms“The Pump” Musculo-skeletal :

rib cage, respiratory muscles, pleura

Conducting Airways : nose, pharynx, larynx, trachea, bronchi

Gas exchange surface: alveoli

Defense mechanismsHeart-lung interactions

Defense mechanisms

Clearance by Physical-physiological

– Rapid bulk removal

Cellular detoxification orImmunologic processing

Physical-physiologicalAgainst penetration and retention

– Gases: Humidification, Dilution, Neutralization,

Absorption– Particulates: Filtration– Laryngeal closure– Bronchospasm– Slow breathing, breathholding

Removal– Coughing, sneezing, gagging– Mucociliary transport– Alveolar clearance

A physiologic defense response may result in disease

Clearance by Cellular detoxification orImmunologic processing Highly controlled inflammatory

pathways = physiologic responseAmplified-uncontrolled expression of

those pathways = disease

Exposure

Impact onSignaling molecules-pathways Target cells responses

Altered homeostasis

InflammationStructural remodeling eg collagen + or –

e.g. Fibrosis or Emphysema

Gene polymorphisms determine responses

In blood, bronchial secretions, tissue:

Cells Macrophages Neutrophiles Eosinophiles Lymphocites Mast cells Basophiles Giant cells

Humoral Signaling moleculesEicosanoids:

– cytokines,– tachykinins,– reactive species – surfactant

proteinsAntiproteasesDefensins

SmokingSmoking

Leukocytes Leukocytes

Proteases Proteases

Destruction Destruction emphysemaemphysema

AntiproteasesAlpha 1 antitrypsin

O3O3

NOx

SO2

Activated Macrophage24 hrs to Clear 50%

3 mm/min

2 hours

Via lymphatics

3-4 months to

Clear 50%

Respiratory Diseases Symptoms Signs

Dyspnea on exertion

at rest Cough Expectoration Hemoptysis Wheezing Chest tightness Chest pain Fatigue, Wgt loss

Breathing rate, labored

Wheezes, ronchi

CracklesDullnessBreathsounds

Diagnostic studies

History and physical exam Imaging studies

Chest X-rayComputerized Axial Tomography CT & High Resolution CT

Pulmonary Function Tests : spirometry, lung volumes, diffusing capacityArterial Blood Gases PaO2, PaCO2, pH, HCO3

Exercise stress testing: SaO2 +++ Polysomnography

Invasive procedures

Fiberoptic BronchoscopyTransbronchial biopsyPercutaneous needle biopsyOpen lung biopsyVideo Assisted ThoracoscopyThoracocentesisPulmonary angiography

Bronch, pfts

Pulmonary Function Tests Spirometry

VOLUME

TIME1 SEC

FEV1=forced expiratory volume in first second

FVC = Vital capacity

Spirometry

Computerized Axial Tomography

BRONCHOSCOPY