Chapter 13
The Respiratory
System
Respiration
• Function
– conducting zone - air to lungs
– respiratory zone - alveoli and capillaries
• Processes
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pulmonary respiration
external respiration
respiratory gas transport
internal respiration - alveoli
Upper Respiratory
Structures
• The nose and nasal cavity
• functions
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humidifies “moistens” for 02 diffusion
warms to speed up diffusion
cleans with cilia
Cleans & moistens with mucus
• structures
– nostrils - external nares
– nasal septum
– nasal cavity - houses sinuses
• Paranasal Sinuses
– location
• frontal sphenoid ethmoid maxillary
– functions
• warm moisten and clean
• lighten skull
• speech resonance
– problems
• rhinitis - inflammation of nasal mucosa
• sinusitis - inflammation of sinuses
• Pharynx
– 5 inch muscular pathway for food and air
– Uvula – flap which covers the nasal opening when
swallowing
– tonsils
Lower Respiratory System
• Larynx
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–
–
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“ voice box”
epiglottis - flap closes when you swallow
glottis - slit like passage between vocal cords
vocal folds – vibrate for voice production
Thyroid cartilage- “Adam’s apple”
• Trachea
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windpipe 4 inches
lined w/ cilia , mucus, pseudostratified
C shaped rings of cartilage
Heimlich manuever
tracheostomy - surgical opening
• Bronchi
– right & left
branch into each lung
– bronchial tubes
– bronchioles
– alveolar sacs – alveoli surrounded by capillaries
Breathing or Ventilation
• Factors Involved - 12-15breaths / min
– inspiration - air in
– expiration – air out
MRV 6 L / min
TV 500 ml / breath
– atmospheric pressure
– intrapleural pressure
– Boyle’s Law
• pressure of a gas varies inversely w/ volume
• Inspiration
– air going in
– sequence
•
•
•
•
•
ribs move up and out
diaphragm moves down “Contracts”
larger chest cavity volume up
pressure drops
air goes in
• Expiration
– passive process relaxation of inspiratory muscles
– sequence
•
•
•
•
•
•
ribs down and in
diaphragm relaxes moves up
smaller chest cavity volume down
pressure up
air goes out
abdominal muscles help force out air
• Nonrespiratory Air Movements
– cough
• forces glottis open
– Sneeze- air out thru nasal cavities
– crying & laughing
• short inspirations
– hiccups
• spasms of diaphragm - phrenic nerve
– yawn
• deep inspiration
• Air Volumes and Capacities
– Spirometer *
• measures respiratory capacity
– tidal volume *
• TV 500 ml , normal breathing
– inspiratory reserve volume
• forced inhalation 2100 - 3100 ml
– expiratory reserve volume
• air forced out 1200 ml
– residual volume *
• 1200 ml , keep lungs & alveoli inflated
– inspiratory capacity
• TV & IRV = 3600 ml
– expiratory capacity
• TV & ERV = 1700 ml
– functional residual capacity
• 2400 ml
– vital capacity *
• total amount of exchangeable air 4800 ml
– total lung capacity
• 6000 ml TV + IRV + ERV + RV
– anatomical dead space
• 150 ml
air in conducting passways
• Respiratory Sounds
– bronchial
• air rushing in
– rales
• rasping
– wheezing
• whistling
Respiratory Disorders
• COPD
– chronic obstructive pulmonary disorder
• features
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–
–
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history of smoking
dyspnea - labored breathing
frequent coughing / infections
hypoxic : retain CO2
• emphysema
– pink puffers
– alveoli enlarges , air goes in hard to exhale and
airways collapse
• chronic bronchitis
– blue bloaters
– a lot of mucus inflammation CO2 retained chronic
infections
• Lung Cancer
• 1/3 of all cancer deaths in U.S. & 90% are smokers
• Second leading cause of death in US
– squamous cell
– adenocarcinoma
– small cell carcinoma
Developmental Aspects
• Surfactant
– detergent like lipoprotein
– reduces water cohension & keeps alveoli sacs
inflated
• IRDS
– infant respiratory distress syndrome
– premature babies
• Cystic Fibrosis
– oversecretion of mucus
• SIDS- sudden infant death syndrome
• Asthma
– chronic inflammation of bronchial passageways
• Others
– hypersensitive irritants, tuberculosis & pneumonia,
sleep apnea
Gas Transport
• Transport of Oxygen
– attached to hemoglobin oxyhemoglobin
– temperature effect temp goes up
• more oxygen released into tissues
– pH effect pH drops
• more oxygen released - less hemoglobin
affinity happens during exercise
– impairments of oxygen
• hypoxia
– not enough O2 to cells
– Anemia, blockage, lack of blood
• CO poisoning
– CO binds with hemoglobin
Control of Respiration
• Phrenic and Intercostal Nerves
– move diaphragm and ribs
• Respiratory Centers
– medulla - respiratory rhythm 12-18 breaths/min
– pons - transition from expiration to inspiration
• Factors influencing respiratory rate
– physical
• exercising, talking, coughing, body temp.
– Volition “conscious”
• hold breath, singing
– emotional
• excited scared, sympathetic
– chemical
• levels of CO2 and O2 and pH of blood