 Includes
the tubes that remove the particles
from incoming air
 Transport air to and from the lungs
 Respiration: gas exchange between body
cells and atmosphere

air sacs
 Upper
respiratory tract: nose, nasal cavity,
paranasal sinuses, and pharynx
 Lower respiratory tract: larynx, trachea,
bronchial tree, and lungs
 Nose:

Nostrils: openings for air
 Nasal


Cavity
Nasal conchae: divides cavity into passageways


bone and cartilage for support
Helps increase the surface area of mucous membranes
Mucous Membrane filters, warms, and moistens
incoming air
Ciliary action carries particle
trapped in mucus to the pharynx,
where they are swallowed
 Paranasal


Sinuses
Spaces in the bones of the skull that open into
the nasal cavity
Lined with mucous membranes
 Pharynx:
behind the oral cavity and between
the nasal cavity and larynx

Passageway for air and food
 Larynx:
conducts air and helps prevent foreign
objects from entering the trachea



Composed of muscles and cartilages
Lined with mucous membranes
Contains vocal cords


Vibrate from side to side to produce sound with air
passes
Glottis and epiglottis help prevent foods and
liquids from entering the trachea
 Trachea:
extends into the
thoracic cavity in front of the
esophagus

Divides into the right and left
bronchi
 Bronchial



Tree
Consists of branched air passages
Lead form the trachea to air sacs
Alveoli: at the distal end of the
narrowest tubes

Alveolar ducts
 Lungs





Separated by the mediastinum
Enclosed by diaphragm and
thoracic cage
Visceral Pleura: attaches to the
surface of the lungs
Parietal Pleura lines the thoracic
cavity
Each lobe is composed of
alveoli, blood vessels, and
supporting tissue










In 20 minutes your blood pressure will drop back down to normal.
In 8 hours the carbon monoxide (a toxic gas) levels in your blood stream
will drop by half, and oxygen levels will return to normal.
In 48 hours your chance of having a heart attack will have decreased. All
nicotine will have left your body. Your sense of taste and smell will return
to a normal level.
In 72 hours your bronchial tubes will relax, and your energy levels will
increase.
In 2 weeks your circulation will increase, and it will continue to improve
for the next 10 weeks.
In three to nine months coughs, wheezing and breathing problems will
dissipate as your lung capacity improves by 10%.
In 1 year your risk of having a heart attack will have dropped by half.
In 5 years your risk of having a stroke returns to that of a non-smoker.
In 10 years your risk of lung cancer will have returned to that of a nonsmoker.
In 15 years your risk of heart attack will have returned to that of a nonsmoker.

credit - Healthbolt
 Changes
in size of the thoracic cavity
accompany inspiration and expiration
 Atmospheric
pressure forces
air into the lungs
 Occurs when the pressure
inside the alveoli decreases


Diaphragm moves downward
Thoracic cage moves upward
and out
 Surface
tension aids in lung
expansion
 Elastic
recoil of tissues and
surface tension within alveoli
provide the forces of
expiration

Thoracic and abdominal wall
muscles aid expiration
 Respiratory
cycle: one inspiration
followed by one expiration
 Tidal Volume: amount of air that
moves in/out during a single
respiratory cycle


Inspiration Reserve Volume: additional
air that can be inhaled
Expiratory Reserve Volume: additional
air that can be exhaled
 Residual
Volume: air remaining in the lungs
after a maximal expiration
 Vital Capacity: maximum amount of air a
person can exhale after taking the deepest
breath possible
 Inspiratory
Capacity: maximum volume of air a
person can inhale following exhalation of the
tidal volume
 Functional residual capacity: volume of air that
remains in the lungs after a person exhale the
tidal volume
 Total Lung Capacity: vital capacity + residual
volume
Normal breathing is rhythmic and
involuntary
 Respiratory center: brain stem,
pons, and medulla oblongata
 Medullary rhythmicity area: two
neuron groups




Dorsal respiratory group: basic
breathing rhythm
Ventral respiratory group: increases
inspiratory and expiratory
movements during forceful breathing
Pneumotaxic area: regulates
breathing rate
 Chemicals,
stretching of the lung tissue, and
emotional states
 Chemosensitive area:


Blood concentrations of CO2 and H+ influence
chemoreceptors
Stimulation of these receptors increases
breathing rate
 Peripheral
chemoreceptors: located in the
walls of certain large arteries


Sense low oxygen concentration
Increases breathing rate
 Overstretching
lung tissue triggers an
inflation reflex


Shortens the duration of inspiratory movements
Inflation reflex prevents over-inflation of the
lungs during forceful breathing
 Hyperventilation:

decreases blood CO2
Very dangerous when done before swimming
 Gas
exchange occurs in the alveoli
 Alveoli: tiny air sacs clustered at the distal
ends of alveolar ducts
 Respiratory membrane: consists of alveolar
and capillary walls

Blood and alveolar air exchange gases across
membrane
 Diffusion
across the
respiratory membrane

Partial pressure of a gas is
proportional to the
concentration of that gas in a
mixture or the concentration
dissolved in a liquid



Gases diffuse from regions of
higher partial pressure to lower
partial pressure
Oxygen diffuses from alveolar air
into blood
CO2 diffuses from blood into
alveolar air
 Blood
transports gases between the lungs and
cells
 Oxygen Transport: blood transports O2 with
hemoglobin


Oxyhemoglobin is unstable and releases its O2 in
regions where PO2 is low
More O2 is released when:



Blood concentration of CO2 increases
Blood becomes more acidic
Blood temperature increases
 May
be carried in solution or bound to
hemoglobin, or as a bicarbonate ion


Most is transport in the form of bicarbonate ions
Carbonic anhydrase: enzyme that speeds the
reaction between CO2 and H2O to form carbonic
acid

Dissociates to release H+ and bicarbonate ions
 Anatomy
of Breathing Flash Animation
 http://teachhealthk12.uthscsa.edu/studentresources/Anatomyof
Breathing3.swf