Respiratory System

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Respiratory System
Ch 23
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Respiration
4 PROCESSES

1. Breathing (Pulmonary Ventilation)
2. External Respiration
3. Internal Respiration
4. Cellular Respiration

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Sinus Cavity

• act as resonance chambers for speech
• mucosa warms and moistens the incoming air
• lightens facial bones

4
Pharynx

• Connects nasal cavity and mouth to larynx and
  esophagus
• 1)     nasopharynx- air passage
• pharyngotympanic (auditory) tube- allows middle
  air pressure to become equalized to atmospheric
  pressure
• Adenoids (pharyngeal) tonsils- mass of lymphoid
  tissue
• traps and destroys pathogens
• produces lymphocytes
• helps fight infection
• 2)     oropharynx- serves as a common conduit for
  air and food
• palatine and lingual tonsils
• 3)     laryngopharynx- accommodates both ingested
  food and air
• located at junction where tracheae and esophagus
  splits
• continuous with esophagus

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Pharynx

• Epiglottis- flexible elastic cartilage
• attached to the wall of the pharynx near the base
  of the tongue
• it closes the glottis in the respiratory tract
  (trachea) when food is swallowed
• Larynx- voice box thyroid cart. that attaches to
  hyoid bone superior and cricoid inferior
• Provides open airway
• Junction for food and air
• Voice production

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Olfactory epithelium
Olfactory tract
Olfactory bulb
Nasal conchae
Route of inhaled air
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Trachea
16 C-shaped rings of hyaline cartilage (thyroid
cricoid tracheal cartilage's, includes
epiglottis (elastic cart) make up
larynx Laryngitis- inflammation of the vocal
cords resulting in inability to speak due to
voice overuse, very dry air, bacterial infection,
and inhalation of irritating chemicals Trachea-
held open by rings of hyaline cartilage, so it
won't collapse during pressure changes when
breathing.
 
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Trachea
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Epithelial Lining of the Trachea
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Vocal Cords

• True vocal cords are inferior to false vocal
  cords
• Sound is produced when expelled air is passing
  through the larynx over the vocal cords

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Lungs
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Alveoli
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Alveoli
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Alveoli
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Thoracic Cavity
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Thoracic Cavity
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Partial Pressure Gradients
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Ventilation-Perfusion Coupling
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Mechanics of Breathing

• 2 muscles involved with breathing
• external intercostal muscles
• diaphragm
• Breathing controlled by
• phrenic nerve from medulla
• pons

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Lung Ventilation
760 mm Hg
756 mm Hg
Negative pressure draws air in
Inspiration
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Lung Ventilation
Positive pressure forces air out
768 mm Hg
Expiration
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Lung Volumes
Tidal Volume- 500 ml Vital Capacity- 4800
ml Residual Volume- 1000-1200ml Total Lung
Capacity- 4400-6400ml IRV- 2800 ml ERV-
1000-1200ml Dead Space- 150 ml
What factors affect lung volume?
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• What happens to TV, IRV, ERV, VC during
  exercise?
• TV ?
• IRV and ERV ?
• TLC and VC- doesn't change
•  

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Breathing Centers in the Brain
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Regulation of Breathing
phrenic
CO2 and H triggers breathing reflex in medulla,
not presence of O2
vagus
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Restrictive vs Obstructive Air Flow

• Restrictive- more diff. to get air in to lungs
• Loss of lung tissue
• Decrease in lungs ability to expand
• Decrease in ability to transfer O2 and CO2 in
  blood
• Diseases
• Fibrosis, sarcoidosis, muscular disease, chest
  wall injury, pneumonia, lung cancer, pregnancy,
  obesity
• ? VC, TLC, RV, FRC

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Restrictive vs Obstructive Air Flow

• Obstructive- more diff. to get air out of lungs
• Airway narrows
• Increase in time it takes to empty lungs
• Diseases
• Emphysema, chronic bronchitis, asthma
• ? VC, ? TLC, RV, FRC

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Chronic Obstructive Pulmonary Diseases
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COPD
Chronic bronchitis- (obstructive) inhaled
irritants lead to chronic excessive mucous
production and inflammation and fibrosis of that
mucosa ? the amt of air that can be inhaled use
bronco- dilators and inhalers Emphysema-
(obstructive and restrictive) enlargement of
alveoli alveolar tissue is destroyed resulting
in fewer and larger alveoli inefficient air
exchange smoker's disease ? amt of air that can
be exhaled Asthma- (obstructive disorder) cold,
exercise, pollen and other allergens from
1979-1989 the number of asthmatic deaths doubles
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COPD
Tuberculosis (TB)- (restrictive) infectious
disease cause by bacterium Mycobacterium
tuberculosis. Spread through air borne bacteria
from infected person's cough. Total lung capacity
declines Symptoms fever night sweats, wt. loss,
racking cough, and spitting up blood Polio- TLC
declines (restrictive) Eliminated in U.S. and
Western Hemisphere Still exists in Africa Lung
cancer- promoted by free radicals and other
carcinogens very aggressive and metastasizes
rapidly
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Smokers lung
Normal lung
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Dalton's Law of Partial Pressure
The total pressure of a gas exerted by a mixture
of gas is the sum of the gases exerted
independently.
Air partial pressure (mm Hg) N2 78.6 597 O2 21
.0 159 CO2 0.04 0.3 H2O 0.46 3.7 Total 100 760

Partial pressure is directly related to its in
the total gas mixture. E.g., at 1 atm PO2 159
mm Hg
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Henry's Law
When a mixture of gas is in contact w/a liquid,
each gas will dissolve in the liquid in
proportion to its partial pressure.
Gasses can go in and out of solution e.g., open
soda, get CO2 bubbles (CO2 is under pressure)
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Decompression Sickness
It is caused when N2 enters the blood circulation
and the tissues. When extra N2 leaves the
tissues, large bubbles form. N2 bubbles can
travel throughout the system and into the lungs
and blood routes. Treatment hyperbaric chamber
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Erythrocytes
Function- transport respiratory gases
Lack mitochondria. Why?
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Hemoglobin Structure
Hemoglobin- quaternary structure 2 ? chains and 2
? chains
1 RBC contains 250 million hemoglobin molecules
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Uptake of Oxygen by Hemoglobin in the Lungs
O2 binds to hemoglobin to form oxyhemoglobin
High Concentration of O2 in Blood Plasma High pH
of the Blood Plasma
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O2 pickup CO2 release
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Unloading of Oxygen from Hemoglobin in the Tissues
When O2 is released?deoxyhemoglobin
Low Concentration of O2 in Blood Plasma Lower pH
of the Blood Plasma
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O2 release CO2 pickup
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Carbon Dioxide Chemistry in the Blood
CO2 H2O ? H2CO3 ? HCO3- H
bicarbonate ion
carbonic acid
enzyme carbonic anhydrase
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Transport of Carbon Dioxide from the Tissues to
the Lungs

• 60-70 as bicarbonate dissolved in the
• plasma (slow reaction)
• 7-10 dissolved in the plasma as CO2
• 20-30 bound to hemoglobin as HbCO2
• CO2 hemoglobin ? HbCO2

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Haldane Effect
Haldane Effect- the amt of CO2 transported in the
blood is markedly affected by the degree of
oxygenation of the blood The lower the P02 and
hemoglobin saturation w/O2, the more CO2 that can
be carried by the blood
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Carbon Monoxide Poisoning

• CO poisoning (hypoxemia hypoxia)
• CO binds 200x more readily w/hemoglobin
• acts as a competitive inhibitor
• symptoms cherry red lips, confused, headache
• does not produce characteristic signs of hypoxia
  (cyanosis and respiratory distress)
• treatment hyperbaric chamber

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INQUIRY

• Identify the lipoprotein molecule that reduces
  surface tension within the alveoli so they do not
  collapse during exhalation.
• Even after the most forceful exhalation, a
  certain volume of air remains in the lungs. What
  is the volume of air called?
• Describe the physical structure of alveoli.
• What structures warm and moisten incoming air?
• What body cavity are the lungs located?
• What tissue lines the lungs?
• What stimulates the breathing response?
• Calculate total lung capacity given
• RV 1000, TV 500, ERV 1100, IRV 2500, VC
  4100