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: 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

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