The Respiratory System
3 Main Functions

Supply O2 to the blood

Remove CO2 from blood

Regulate blood pH (acid-base balance)

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External respiration: processes that occur within
the lung involving the exchange of O2 and CO2
Internal respiration: exchange of gases at tissue
level, O2 is delivered and CO2 is removed
Cellular respiration: process where the cells use
O2 to generate energy through the different
metabolic pathways
Respiratory System Structure

Structures of the respiratory system can be
divided into two main zones:

Conductive zone

Respiratory zone
Conductive Zone


Composed of all of
the structures that
convey air form the
outside of the body
through the lungs
Includes: mouth and
nose, pharynx, larynx,
trachea, primary and
secondary bronchi,
tertiary bronchioles
and terminal
bronchioles
Respiratory Zone



Composed of respiratory bronchioles, alveolar
ducts, and alveolar sacs
All of these structures are involved with the
exchange of gases between inspired air and the
blood
Alveolar sacs (alveoli) are grape-like structures
that provide a large surface area for the
diffusion of gases into and out of the blood

Mechanisms of
Breathing
Movement of air from
outside of the body to
the inside of the body
is dependent on
differences in air
pressure

Air moves from
regions of higher
pressure to regions of
lower pressure
Diaphragm



Diaphragm: large flat specialized muscle. With
stimulation from the brain, it contracts and
moves downward to create more space in the
chest cavity. This results in a decline in air
pressure within the chest and lungs
With the contraction of the diaphragm, the air
pressure within the chest cavity is lower than
the air pressure outside the body
This results in inspiration – air rushing into the
lungs from outside
Video

http://www.youtube.com/watch?v=vu_ONM3Bj9
A&feature=related
Ventilation

Ventilation = the combination of inspiration and
expiration




The volume of air that is moved by the lungs in one
minute
Influenced by two factors: the volume of air in
each breath, and the number of breaths taken
Tidal Volume = the volume of air in each breath
Respiratory Frequency = number of breaths
taken per minute
Adaptations to Training


Regular aerobic training leads to very few
adaptations in the respiratory system
The only observable changes with training are
in ventilation (combination of inspiration and
expiration)

Increase in tidal volume (Vt) and decrease in
respiratory frequency (f)
Respiratory Disease


Asthma: spasm of the smooth muscle that lines
the respiratory system

Oversecretion of mucous

Swelling of the cells lining the respiratory tract
http://www.youtube.com/watch?v=qW2KL6TsF
Ck&NR=1
COPD




COPD: Chronic Obstructive Pulmonary
Disease
Describes a family of disease that lead to a
dramatic reduction in airflow
Differs from asthma in that the conditions
persist and cannot be relieved as quickly or as
effectively with medication
People with COPD cannot perform everyday
activities without experiencing dyspnea
(laboured breathing)