Download The Respiratory System

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/Swall
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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