Download Respiratory system

Respiratory system
Organs of the respiratory system

Upper respiratory tract
 Nose

Internal hairs guard the nostrils and prevent entry of large
particles
 Nasal

cavity
Extensive network of blood vessels that warms the air to that
of the body
 Paranasal

sinuses
Reduce the weight of the skull and are resonant chambers
that affect the sound of the voice
 Pharynx

Helps produce sounds of speech
Organs of the respiratory system

Lower respiratory tract
 Larynx
 Prevents foreign objects from entering trachea
 Houses vocal cords
 Glottis


Opening/ lumen of the larynx
Epiglottis

Cartilage flap that closes the trachea during swallowing
 Trachea
 Bronchial
 lungs
tree
Breathing mechanism

Pulmonary ventilation is the movement of
air from outside the body into the bronchial
tree and alveoli followed by the reversal of
this air movement
 Actions
responsible for these air movements
Inspiration
 expiration

Inspiration
Atmospheric pressure is the force that
causes air to move into the lungs
 If pressure inside lungs and alveoli
decreases outside air will be pushed into
the airways

 Surface
tension holds the surfaces of pleural
membranes together allowing expansion of
lungs in all directions

Sufficient to cause alveoli to collapse

Produce surfactant to decreases the tendency to
collapse
Expiration

Passive process
 Lungs
and thoracic cage recoil and return to
normal shape
 Abdominal organs recoil and push upward on
diaphragm
 Surface tension of alveoli decrease the
diameter

These factors cause an increase in pressure

Cause air to be forced out of respiratory passages
Respiratory air volumes





Tidal volume- the total amount of air that enters and
leaves in a normal breath
Inspiratory reserve volume- additional volume added to
tidal volume during forced inspiration
Expiratory reserve volume- additional volume plus tidal
volume during forced expiration
Residual volume- amount of air that remains even after
the most forceful expiration
Vital capacity- inspiratory reserve volume combined with
the tidal volume and the expiratory reserve volume


Lung capacity- vital capacity plus residual volume


The maximum amount of air a person can exhale after taking the
deepest breath possible
Total varies with age, sex, and body size
Dead space- areas in trachea, bronchi, and bronchioles
where air gets trapped and there is no gas exchange
Control of breathing
 Respiratory
Medullary
 Two
center
rhythmicity
groups of neurons
Dorsal
respiratory group
 Basic rhythm of breathing
Ventral
respiratory group
 More forceful breathing
 Activate muscles that are associated with
more forceful expirations
Control of breathing
 Pneumotaxic
Control
area
the rate of breathing
 Transmits
impulse to the dorsal respiratory
group continuously
 Regulates the duration of the inspiratory
burst
 When
the pneumotaxic signals are strong the
inspiratory burst have shorter durations and the
rate of breathing is increased, when the
pneumotaxic signals are weak the inspiratory
burst have longer burst and the rate of
breathing is decreased
Factors affecting breathing

Chemicals in body fluids
 Increases
with high concentrations of carbon dioxide
or hydrogen ions

Degree to which lung tissue is stretched
 Inhalation reflex- regulates the depth of breathing
 Stimulated when respiratory organs are stimulated as a result
of the lungs being over stretched


Shortens the inspiratory movements
Emotional state
 respiratory
muscles are voluntary and can be altered
consciously
Alveolar gas exchange

Alveoli
 Microscopic
clusters of air sacs
 Respiratory membrane
separates the air in the alveolus with the blood in
the capillary
 Gas exchange occurs here

Alveolar gas exchange



There is a difference in partial pressure in
capillary blood and alveolar air
Because of the difference between these partial
pressures, carbon dioxide diffuses from the
blood where its pressure is higher through the
respiratory membrane and into the alveolar air.
Oxygen diffuses from the alveolar air into the
blood as a result a pressure differences
Transport of gases

Oxygen transport
 Almost
all oxygen is combined with
hemoglobin

This chemical reaction produces oxyhemoglobin

Relatively unstable bonds and as oxygen pressure (Po2)
decreases oxygen is released
 Happens in tissues where cells have used oxygen in
their respiratory process
Transport of Gases

Oxygen release factors
 Concentration
 Blood

pH
More acidic
 Blood

of CO2 in blood
temperature
As these increase more oxygen is
released
Transport of gases

Carbon dioxide transport
 CO2

is transported to lungs in 1 of 3 ways
As CO2 dissolved in blood


as part of a compound formed by bonding to
hemoglobin


Determined by partial pressure
carbaminohemoglobin
As part of a bicarbonate ion
CO2 reacts with water forming carbonic acid
 Then dissociates releasing H+ and bicarbonate ions


Blood passes through lung capillaries and
CO2 diffuses out