Transcript The Respiratory System

The Respiratory System
System Overview
• Includes tubes that remove
particles from incoming air
and transport air in and out
of the lungs
• Microscopic air sacs for
gas exchange
• Organs include:
– Nose, nasal cavity, and
paranasal sinuses
– Pharynx
– Larynx
– Trachea
– Bronchial tree
– Lungs
Steps of Respiration
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1.
2.
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4.
Respiration = the process of gas exchange
between the atmosphere and body cells
Ventilation
Gas exchange between blood and air in
lungs
Gas transport between lungs and body
cells
Gas exchange between blood and body
cells
Upper and Lower Respiratory
Tracts
• Upper Respiratory
Tract
– Organs located outside
the thorax
• Lower Respiratory
Tract
– Organs located within
the thorax
The Nose
• Supported by bone and
cartilage
• Nostrils
• Nasal cavity
• Nasal septum
• Nasal conchae
– Support mucous
membranes
– Pseudostratified columnar
epithelium and goblet
cells
– Extensive network of
blood vessels to warm air
Paranasal Sinuses
• Air-filled spaces
within:
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–
Maxillary bones
Frontal bone
Ethmoid bone
Sphenoid bone
• Reduce skull weight
• Resonance chambers
Pharynx
• Behind the oral cavity
and between the nasal
cavity and the larynx
• Passageway for food
and air
• Helps produce speech
Larynx
• Enlargement at the top of
the trachea and below the
pharynx
• Conducts air in and out of
the trachea
• Prevents foreign objects
from entering trachea
• Houses vocal cords
• Epiglottis
Vocal Cords
• Horizontal folds of muscle and
CT with a mucous membrane
covering
• False vocal cords
• True vocal cords
• Speech is formed by changing
the shape of the pharynx and
oral cavity
– Words formed by the tongue and
lips
– Loudness
– Pitch
• Glottis
Trachea
• AKA windpipe
• Extends in front of the
esophagus and into the
thoracic cavity
• Splits into left and right
bronchi
• Ciliated epithelium and goblet
cells
– Filters incoming air
– Sweeps particles out into
pharynx
• 20 hyaline cartilage rings
• Soft tissue on posterior 
esophagus can expand as food
is swallowed
Bronchial Tree
• Branched airways
leading from trachea to
lungs
• Structurally similar to
trachea with less
cartilage
• Mucous membranes filter
incoming air and
distribute air to alveoli
Passage of Air Though the
Bronchial Tree
• Primary bronchi 
secondary bronchi 
bronchioles 
alveolar ducts 
alveoli
Lungs
• Soft, spongy, cone-shaped
organs in thoracic cavity
• Lungs separated by the
heart
• Enclosed by thoracic cage
and diaphragm
• Suspended from bronchi
and some large blood
vessels
• Right lung (3 lobes) is
larger than left (2 lobes)
• Visceral pleura
Alveoli
• Microscopic air sacs
• Clustered at distal ends of
alveolar ducts
• Consist of tiny spaces
within simple squamous
epithelium walls
• Dense capillary network
• Large surface area for gas
exchange
• Surfactant
Breathing
•
Breathing consists of 2 processes:
1. Inspiration (inhalation)
2. Expiration (exhalation)
•
Air moves into the lungs because of
atmospheric pressure.
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When lung pressure is lower than atmospheric
pressure because of diaphragm and intercostal
muscle contractions  inspiration
When muscles relax and lungs and thoracic
cage return to normal size  expiration
Control of Breathing
• Controlled by the
respiratory center of the
medulla oblongata and the
pons
• May also be affected by
– Chemicals in body fluids
(CO2, H+, O2)
– Degree to which lung tissue
stretches
– Emotional state
– Hyperventilation