Download The Respiratory System

The Respiratory System
Involves the
exchange of
gases between
cells, blood and
the atmosphere
Types of Respiration

Pulmonary ventilation
inspiration
 expiration
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External respiration
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occurs in the lungs
Internal respiration
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occurs in the tissues
Organs of Respiration
Nose,
Pharynx,Larynx,Trachea,
Bronchial Tree, Lungs
NOSE
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Moistens, warms, and
filters air
Houses olfactory
receptors
Serves as resonating
chamber for speech
Nasal septum divides
nasal cavity
PALATE
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Serves to separate the nasal cavity
from the oral cavity
Hard palate
Soft palate
Uvula
PHARYNX
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Nasopharynx - upper portion, region
above the soft palate
Oropharynx - middle portion, area
behind the oral cavity
Laryngopharynx - lower portion, area
below the epiglottis
LARYNX
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Functions to prevent food or fluid from
entering the respiratory system during
swallowing and allows air flow during
breathing
Production of sound is secondary
function
Larynx
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Unpaired cartilages - thyroid, cricoid,
epiglottis
Paired cartilage - arytenoid,
corniculate, cuneiform
Vocal folds
Glottis
TRACHEA
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Tubelike structure leading from the
larynx to bronchial tree
Consists of smooth muscle and “C”
shaped hyaline cartilage rings
Lined with psuedostratified ciliated
columnar epithelium
Mucociliary escalator
BRONCHIAL TREE
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Includes a right and left primary
bronchus which divides to produce
secondary bronchi, tertiary bronchi and
bronchioles
Terminal bronchioles branch into
respiratory bronchioles which divide
into alveolar ducts that connect to
alveoli
ALVEOLI
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Functional unit of the lungs where
gas exchange occurs (300 million)
Thin walls made of simple squamous
epithelium
Type I and type II alveolar cells
Diffusion of gases takes place across
an alveolar-capillary respiratory
membrane
LUNGS
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Paired organs in the thoracic cavity
Right lung : 3 lobes
 horizontal/oblique fissure
Left lung : 2 lobes
 oblique fissure
Apex/Base
Hilus
PLEURAL MEMBRANES
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Parietal pleura
Visceral pleura
Pleural cavity
Pleurisy
Pneumothorax
Physiology of Respiration
Pressures
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Atmospheric pressure - 760mm Hg
Intrapleural pressure - is always less
than atmospheric and alveolar pressure
Alveolar (intrapulmonary) pressure changes with phases of breathing
Pressure changes in lungs are produced
by variations in lung volume
BOYLE’S LAW
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The pressure of a gas is inversely
proportional to its volume
More volume-less pressure
Less volume - more pressure
Inspiration
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Alveolar pressure is
below atmospheric
pressure due to
increased volume
Air flows into lungs
760 vs 758 mm Hg
Expiration
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Alveolar pressure is
above atmospheric
pressure due to
decreased volume
Air flows out of lung
762 vs 760 mm Hg
Respiratory Air Volumes
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Tidal volume
Inspiratory reserve volume
Expiratory reserve volume
Vital capacity
Residual volume
Spirometer
Regulation of Respiration
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Medullary rhythmicity center - medulla
oblongata controls basic rhythm of
respiration
Control centers in the pons
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pneumotaxic center inhibits inspiration
apneustic area stimulates inspiration
Gas Transport
Oxygen Transport
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98% of oxygen is bound to hemoglobin
as oxyhemoglobin
Each hemoglobin molecule has the
capacity to bind with four oxygen
molecules
Hypoxia
Factors Affecting Hemoglobin
Saturation

Partial pressure of oxygen
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increase pO2, the greater the % saturation
pH - in an acid environment, O2 splits
more readily from hemoglobin
Temperature - the higher the
temperature, the more oxygen released
from hemoglobin
Carbon dioxide tranport
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70% of CO2 is transported in the plasma
as bicarbonate ion
23% of CO2 is bound to the globin part
of hemoglobin as carbominohemoglobin
7% is dissolved in the plasma
RESPIRATORY DISORDERS
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COPD (Chronic
Obstructive
Pulmonary Disease)
Asthma
Bronchitis
Emphysema
Lung Cancer
Tuberculosis
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Cystic Fibrosis
Cheyne-Stokes
Respiration
Pneumonia
Sleep Apnea
SIDS