copyright © 2006 pearson education, inc., publishing as benjamin cummings respiratory system take a...
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Respiratory System
Take a big whiff!
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Why do we need to breathe?
All cells need oxygen
Cellular Respiration: Process of breaking down glucose into ATP
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Organs of the Respiratory systemNose
Pharynx
Larynx
Trachea
Bronchi
Lungs –
alveoliFigure 13.1
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Function of the Respiratory SystemOversee gas exchanges between the blood and external environment (air)
Exchange of gases takes place within the lungs in the alveoli
Passageways to the lungs purify, warm, and humidify the incoming air
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Upper Respiratory Tract
Figure 13.2
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Pharynx & Tonsils
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Larynx (Voice Box)
Routes air and food into proper channels
Plays a role in speech
Made of eight rigid hyaline cartilages and a flap of elastic cartilage (epiglottis)
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Trachea (Windpipe)
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Lungs
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Respiratory Tree Divisions
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Respiratory Tree Divisions
1o (primary) bronchi
2o (secondary) bronchi
3o (tertiary) bronchi
Bronchioles
Terminal bronchioles
Alveoli
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Bronchioles
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Respiratory Membrane (Air-Blood Barrier)
Simple squamous epithelium lines alveolar walls
Pulmonarycapillaries cover ext. surfaces of alveoli
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Respiratory Membrane (Air-Blood Barrier)
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Respiratory Membrane (Air-Blood Barrier)
Figure 13.6
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Gas Exchange
Gas crosses the respiratory membrane by diffusion
O2 enters the blood (from alveoli)
CO2 enters the alveoli (from blood)
Macrophages add protection
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Mechanics of Breathing (Pulmonary Ventilation)
Completely mechanical process
Depends on volume changes in the thoracic cavity
Volume changes lead to pressure changes, which lead to the flow of gases to equalize pressure
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Mechanics of Breathing (Pulmonary Ventilation)
Two phases
Inspiration (inhalation)– flow of air into lung
Expiration (exhalation) – air leaving lung
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Inspiration (a.k.a. Inhalation)
Diaphragm and intercostal muscles contract
The size of the thoracic cavity increases (decreasing pressure)
External air is pulled into the lungs due to an increase in intrapulmonary volume
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Expiration (a.k.a exhalation)
Largely a passive process
Depends on natural lung elasticity
As muscles relax, air is pushed out of the lungs
Forced expiration can occur mostly by contracting internal intercostal muscles to depress the rib cage
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Oxygen Transport in the Blood
Inside red blood cells attached to hemoglobin (oxy-hemoglobin)
A small amount is carried dissolved in the plasma
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Carbon Dioxide Transport in the BloodMostly transported in the plasma
A small amt is carried inside red blood cells on hemoglobin
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Gas Exchange
Figure 13.11
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Cilia
Cilia – tiny hairs that beat debris up & out of lungs.
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Mucus a.k.a Phelm
Mucus – warms, moistens, & filters the air.
- To be swallowed or spit out.
Avg Person – 1 liter of phelm a day!
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Factors Influencing Respiratory Rate and Depth
Physical factors Increased body temperature Exercise, Talking, Coughing
Volition (conscious control) Emotional factors Carbon dioxide levels Oxygen levels
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Respiratory Disorders: Chronic Obstructive Pulmonary Disease (COPD)Chronic bronchitis
Emphysema
Major causes of death and disability in US
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Respiratory Disorders: Chronic Obstructive Pulmonary Disease (COPD) COPD patients:
history of smoking (usually)
labored breathing (dyspnea) Worsens over time
coughing and frequent lung infections
Often develop respiratory failure
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Lung Cancer
1/3 of all cancer deaths in US
associated w/ smoking
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Emphysema
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Asthma
Chronic inflamed hypersensitive bronchioles
Response to irritants – constriction, coughing, and wheezing
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Birth Defects
Cystic fibrosis – oversecretion of thick mucus clogs the respiratory system
Cleft palate
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Aging
Elasticity of lungs decreases
Vital capacity decreases
Blood oxygen levels decrease
Stimulating effects of carbon dioxide decreases
More risks of respiratory tract infection
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Lung Model
Cut bottom off small water bottle
Tie fingers from 1 gloveCover bottom of bottle with cuff of glove
Tape to seal Insert deflated balloonWrap mouth-piece of balloon over top of bottle