NESCAUM Health Effects Workshop, Bordentown, NJ Physiology 101 NESCAUM Health Effects Workshop, Bordentown, NJ Joann Held July 29, 2008

VENTILATION: The process of moving air in & out of the lungs Tidal Volume: Volume of air entering or leaving the lungs during a single breath Vital Capacity: Tidal volume + Inhalation reserve + Expiration reserve Residual Volume: What’s left after forced exhalation Expiration does not empty the lungs completely. If it did, the alveoli would collapse, and it would take a lot of work and energy to reinflate the lungs. Also, blood is perpetually circulating through the lungs… So, even after a very deep exhalation, the lungs remain about one-fifth full of air - an amount called the residual volume.

Lung Function Testing A method for evaluating whether the respiratory system has been impaired

Spirometry Tidal Volume Vital Capacity FEV1 (Volume of air expired in 1 second) FVC (Forced Vital Capacity) PEF (Peak Expiratory Flow) Spirometry is the classic pulmonary function test, which measures the volume of air inspired or expired as a function of time. It can monitor quiet breathing and thereby measure tidal volume, And also trace deep inspirations and expirations to give information about vital capacity. Spirometry may also be used to measure forced expiration rates and volumes and to compute FEV1/FVC ratios.

Protective Functions of the Respiratory System Filtration and Preconditioning Impaction and Mucus-transport Pulmonary Clearing

Nasopharynx : aka nasopharyngeal or extrathoracic

Filtration Nasal hair and warm, humid conditions of nasal passages act together to remove particles & soluble gases. Particles absorb moisture as they move through moist air of upper respiratory region, making them larger and causing them to strike walls of throat, nose, etc. Gases that are very soluble can be absorbed before reaching the lower lung. Particles are then eliminated by sneezing, coughing, nose-blowing, and spitting, or by the digestive system.

Impaction

Removal of Smaller Particulate Branching of the bronchopulmonary tree provides opportunity of impaction Fine Particulate: Collect in middle part of respiratory system - the tracheobronchial region

Particle Deposition

Pulmonary Clearance Ultra-fine Particulate & Less Soluble Gases Collect in the most remote portions of lungs - the alveoli In the alveoli they may float and then be expelled with the next breath or two; or They might be captured by phagocytes and eliminated Phagocytes are in the alveolar epithelium and “eat” invaders.

Defense Mechanisms Mucus Membrane Cilia Phagocytes Macrophages Mucus Membrane: Warms the air & moistens it, in order to protect the bronchiolesand alveoli. Cilia (whiplike) found in the mucus membranes lining the nasal cavity & trachea tap particles that might irritate delicate lung tissues. * Alveolar macrophages ingest and destroy invading bacteria and viruses.

GAS EXCHANGE Exchange of oxygen and carbon dioxide between alveolar air & lung capillaries is by diffusion.

Beyond the Lungs: Some Examples DIRECT EFFECTS Chemical Interactions Neurological Impacts INDIRECT EFFECTS Liver Metabolism Kidney Metabolism