1. THE RESPIRATORY SYSTEM PASSAGEWAYS & LUNGS

2. 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

3. 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

4. the EVENTS of respiration:
breathing / ventilation = moving air into or out of the lungs
external respiration = gas exchange between blood & the air in the lungs
gas transport in blood between the lungs & body cells
internal respiration = gas exchange between blood & body cells
cell respiration = using O2 to break glucose & form ATP

5. 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

6. UPPER respiratory tract

7. 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

8. 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

9. lower respiratory tract

11. 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

12. 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

13. 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

14. 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

15. 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

16. blood transport of gases:
cellular respiration = the process by which cells use oxygen to break down glucose (via glycolysis) & release energy to form ATP

17. 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

19. 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

20. 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

21. 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

23. 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

24. 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)

25. 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

26. 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

27. 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

28. RELEVANT VOCABULARY
emphysema = a progressive, degenerative disease that destroys alveolar walls therefore reducing the volume of gas exchange

29. 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

30. spirometer = an instrument that measures respiratory air volume
tracheotomy = incision in the trachea for exploration or for removal of a foreign object