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The Respiratory System
for student copy
Functions of the Respiratory System
• Gas Exchange
Organs of the Respiratory System
• Upper Respiratory Tract– Nose– Pharynx– Larynx
• Lower Respiratory Tract– Trachea – Bronchi– Lungs
Nose
• framework composed of bone & cartilage• 2 nostrils called: external nares– where air enters the nasal cavity– rt & lt separated by nasal septum• site of nose bleeds@ internal edge: internal nares
Pharynx
• throat • 3 divisions:1. Nasopharynx– begins @ internal nares end of soft palate
2. Oropharynx– edge of soft palate hyoid bone
3. Laryngopharynx – hyoid bone upper edge of esophagus
3 Parts of the Pharynx
Larynx
• “voice box”• Cartilage• Parts:– Epiglottis– Glottis– Thyroid cartilage– Cricoid cartilage
Larynx
• moves upward when you swallow – tips epiglottis over the glottis (opening of trachea)– allows food esophagus (--/ down trachea to lungs)– if not swallowing: glottis is open allowing air lungs
– http://www.linkstudio.info/images/portfolio/medani/Swallow.swf
Trachea• rings of cartilage maintain its shape to prevent it
from closing• forks into 2 bronchi
Bronchus
• each enters a lung where it branches into smaller & smaller bronchioles resembling an inverted tree
Bronchioles
• fine tubes that allow passage of air• smooth muscle surrounds them when
contracts airways constrict• epithelium covered with cilia & mucus
• mucus traps dust, particulates• cilia beat upward removing trapped particles from
airways (moves particles ~1-3 cm/hr)
Bronchioles
Gas Exchange in Lungs
Pulmonary Function Tests
• “PFTs”• subject breathes into a closed system in which
air is trapped w/in a bell floating in water• bell moves up when patient exhales / down
when they inhale
Pulmonary Function Tests
• Tidal Volume:– amt of air expired
• Vital Capacity:– max amt of air that can
forcefully exhaled after a max inhalation
Spirogram
Anatomical Dead Space• not all inspired air will get into the lungs • exhaling does not force all air out of the body
Hemoglobin
• helps transport oxygen, carbon dioxide, & buffer blood
• as carbon dioxide leaves cells & diffuses thru interstial fluid then into capillary it combines with water to form carbonic acid
Hgb Loading & Unloading Oxygen
Respiratory pH Balance
Respiratory Acidosis
• hypoventilation • accumulation of CO2 in
tissues• pH decreases• plasma HCO3- increases
Respiratory Alkalosis
• hyperventilation• excessive loss of CO2
• pH increases• plasma HCO3- decreases• CO2 in blood increases