HUMAN PHYSIOLOGY

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HUMAN PHYSIOLOGY

• ..a brief review of the normal physiological
  functioning of selected human body systems.

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Respiratory System

• Consists of
• Nose
• Mouth
• Upper Throat
• Larynx
• Traches
• Bronchi

• Lungs
• Diaphragm
• Muscles of chest

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Nose vs. Mouth

• Nose
• Air is warmed and moistened
• Mucus membranes
• Cilia
• Mouth

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Throat

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

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Larynx

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

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Trachea (Windpipe)

• 4.5 long / 1 in diameter
• Extends from bottom of larynx through neck, and
  into chest cavity
• Lined with mucus membrane and cilia
• Divides into left and right bronchi

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Bronchi

• Branches to left and right lungs

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Lung Anatomy

• Composed of
• Pleura
• Alveoli

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Types of Lung Deposition

• IMPACTION occurs at branching
• SETTLING increases with penetration into the
  respiratory system
• DIFFUSION - significant only for smallparticles
  in the alveoli

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Particle Deposition

• Particles gt 8-10 um removed in nasal area
• Particles 2.5-3 um generally deposited in upper
  respiratory system
• Particles approximately 2 um generally deposited
  in upper respiratory system and alveolar or
  pulmonary airspaces
• Particles 1 um deposited in alveolar spaces

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Fate of Deposited Particle

• Determined by
• Size
• Solubility
• Chemical reactivity

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Dust-laden air can do damage if...

• concentration exceeds bodys ability to eliminate
  it
• is chemically or phys-iologically damaging
• initiates allergic action
• is inhaled by an impaired respiratory system

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Natural Defenses

• Warming/cooling, humidifying
• Mucus lining
• Cilia
• Branching respiratory tree
• Muscular contraction