Transcript THE RESPIRATORY SYSTEM

THE RESPIRATORY SYSTEM
PASSAGEWAYS & LUNGS
FUNCTIONS of the respiratory system:
– #1 = obtaining oxygen & removing
carbon dioxide = gas exchange
– filtering incoming air
– controlling the temp & water content of
incoming air
– producing vocal sounds
– plays important roles in the sense of
smell & regulation of blood pH
cleaning dirty air:
– there’s millions of particles of foreign
matter in air!
– air must be filtered before it reaches the
lungs
– the nasal cavity, trachea, & bronchial tree
are all lined with ciliated cells that secrete
mucus via goblet cells
– the cilia beat upward towards the
pharynx, where foreign matter is
swallowed or coughed up
the EVENTS of respiration:
1) breathing / ventilation = moving air into
or out of the lungs
2) external respiration = gas exchange
between blood & the air in the lungs
3) gas transport in blood between the
lungs & body cells
4) internal respiration = gas exchange
between blood & body cells
• cell respiration = using O2 to break
glucose & form ATP
PARTS of the respiratory system:
upper respiratory tract
– nose w/ 2 nostrils
– nasal cavity / nasal passages
• divided into R & L by the nasal
septum (may be deviated)
– paranasal sinuses = air-filled spaces in
the bones of the skull
– pharynx = a passageway for air & food
UPPER respiratory tract
PARTS of the respiratory system:
lower respiratory tract
– larynx = contains the vocal cords
– Trachea = “windpipe”
– bronchial tree – branched air passages that
lead from the trachea to the air sacs, or
alveoli
parts of the respiratory system:
LOWER respiratory tract
– 2 lungs: the right lung has 3 lobes &
the left has 2 lobes
– assisted by the diaphragm
– controlled by the medulla
oblongata & pons
in the brain stem
lower respiratory tract
the PATH air takes:
– air is taken in through the nose or mouth
= inspiration
– air flows into the pharynx & passes the
epiglottis
– it moves through the larynx (voicebox)
– it travels down the trachea which splits
into 2 tubes
the PATH air takes:
– a bronchial tube / bronchus leads into
each lung
– It branches into smaller bronchioles
– Bronchioles end in alveoli where gas
exchange takes place
– this pathway is reversed for expiration
alveoli = the place of gas
exchange:
– the bronchi branch like a tree
(bronchus bronchioles alveoli)
– alveoli are the sacs of the lungs where
O2 & CO2 are exchanged by diffusion
between the air and blood
alveoli = the place of gas
exchange:
– grape-like clusters of alveoli are
surrounded by networks of tiny blood
vessels / capillaries
– the walls of capillaries and of alveoli are
only 1 cell thick
blood transport of gases:
– external respiration = the exchange of
O2 & CO2 between the air in the alveoli
and the blood that circulates through its
capillaries
– once oxygen diffuses into the
bloodstream, it is pumped by the heart
to all cells in the body
blood transport of gases:
– cellular respiration = the process by
which cells use oxygen to break down
glucose (via glycolysis) & release
energy to form ATP
blood transport of gases:
– carbon dioxide is a waste product & it
diffuses into the blood which carries it
back to the lungs, then it is exhaled
– blood going into the alveoli is low in O2
& high in CO2
– blood returning from the alveoli is higher
in O2 & low in CO2
lung capacity:
– tidal volume = the amount of air that
moves in during a respiratory cycle (1
inhalation + 1 expiration)
– residual volume = air remaining in lungs
after a maximal exhale
– vital capacity = the maximum amount of
air a person can exhale after taking in
the deepest breath possible
– total lung capacity = the vital capacity +
the residual volume
THE MECHANICS OF
BREATHING 
• breathing is accomplished via the action of
the diaphragm & the muscles between the
ribs & is assisted by air pressure
• inhaling contracts the muscles between
the ribs & causes the rib cage to rise
• inhaling also contracts the diaphragm,
flattening it, causing it to move lower in
the chest cavity
THE MECHANICS OF
BREATHING 
• both of these muscular contractions
increase the space in the chest cavity,
which creates a slight vacuum
• air rushes to fill the space because the
pressure outside your body is greater than
the pressure inside your lungs
THE MECHANICS OF
BREATHING 
• when you exhale (expiration), the rib
muscles & diaphragm relax which lowers
the rib cage & diaphragm
• this decreases the volume of the chest
cavity & forces air out of the alveoli
THE MECHANICS OF
BREATHING 
• healthy lungs are elastic: they stretch as
you inhale & go back to their original size
when you exhale
• they are never completely empty – even
after exhaling (residual volume)
CONTROL OF RESPIRATION 
• usually respiration is involuntary
• the respiratory center is in the brain stem
& includes portions of the pons & medulla
oblongata
• it is partially controlled by the medulla
oblongata which maintains the
homeostasis of blood chemistry
CONTROL OF RESPIRATION 
• the medulla oblongata responds to higher
levels of CO2 in blood by sending nerve
impulses to the rib muscles & the
diaphragm, causing these muscles to
contract & you inhale
RELEVANT VOCABULARY
• apnea = temporary cessation of breathing
• asphyxia = O2 deficiency & excess CO2 in
blood & tissues
• bronchitis = inflammation of the bronchial
lining
• cystic fibrosis = a genetic disorder which
causes the production of extremely thick,
sticky mucus which encourages infection +
clogs the pancreas + impairs absorption of
nutrients + leads to salty sweat
RELEVANT VOCABULARY
• emphysema = a progressive, degenerative
disease that destroys alveolar walls
therefore reducing the volume of gas
exchange
RELEVANT VOCABULARY
• hyperventilation = prolonged rapid & deep
breathing
• pleurisy = inflammation of the pleural
membranes
• rhinitis = inflammation of the nasal cavity
lining
• sinusitis = inflammation of the sinus cavity
lining
• spirometer = an
instrument that measures
respiratory air volume
• tracheotomy = incision in
the trachea for
exploration or for removal
of a foreign object