HUMAN PHYSIOLOGY …..a brief review of the normal physiological functioning of selected human body systems.

Respiratory System Consists of… n Nose n Mouth n Upper Throat n Larynx n Traches n Bronchi n Lungs n Diaphragm n Muscles of chest

Nose vs. Mouth Nose… n Air is warmed and moistened n Mucus membranes n Cilia Mouth…

Throat n Nasal cavity pharynx (throat) n Nasopharynx –Upper ext. of throat –Defender against infectious organisms n Esophagus (food/liquids to stomach) & trachea (air/gases to lungs) n Epiglottis –guards opening of trachea

Larynx n Serves as passageway for air between pharynx and trachea n Exhalation via larynx controlled voluntarily voice organ n Lined with ciliated mucus membranes n Vocal cords in front of larynx

Trachea (Windpipe) n 4.5” long / 1” in diameter n Extends from bottom of larynx through neck, and into chest cavity n Lined with mucus membrane and cilia n Divides into left and right bronchi

Bronchi n Branches to left and right lungs

Lung Anatomy Composed of: n Pleura n Alveoli

Types of Lung Deposition n IMPACTION –occurs at branching n SETTLING – increases with penetration into the respiratory system n DIFFUSION - significant only for small particles in the alveoli

Particle Deposition À Particles > 8-10 um removed in nasal area Á Particles um generally deposited in upper respiratory system Á Particles approximately 2 um generally deposited in upper respiratory system and alveolar or pulmonary airspaces Á Particles 1 um deposited in alveolar spaces

Fate of Deposited Particle Determined by… n Size n Solubility n Chemical reactivity

Dust-laden air can do damage if... n concentration exceeds body’s ability to eliminate it n is chemically or phys- iologically damaging n initiates allergic action n is inhaled by an impaired respiratory system

Natural Defenses n Warming/cooling, humidifying n Mucus lining n Cilia n Branching respiratory tree n Muscular contraction