Respiratory SystemRespiratory System

Anatomy and PhysiologyAnatomy and Physiology

FunctionsFunctions Delivering air to the lungsDelivering air to the lungs Bringing oxygen into the bodyBringing oxygen into the body

– Diffuses ODiffuses O22 from lungs into blood from lungs into blood

– Circulatory system takes over to deliver OCirculatory system takes over to deliver O2 2 to cellsto cells

– Why do we need OWhy do we need O22??To maintain our energy levels/make ATPTo maintain our energy levels/make ATP

Expelling the carbon dioxide back into the air to Expelling the carbon dioxide back into the air to help maintain blood pHhelp maintain blood pH– Diffuses CODiffuses CO22 from blood into lungs from blood into lungs

COCO22 and H and H22O when mixed makes carbonic acid and lowers O when mixed makes carbonic acid and lowers pH of blood.pH of blood.

Parts of the Respiratory SystemParts of the Respiratory System NoseNose – provide opening for air to enter/exit nasal – provide opening for air to enter/exit nasal

cavitycavity Nasal Cavity Nasal Cavity – hollow space behind the nose, – hollow space behind the nose,

conducts air to pharynx, sense of smellconducts air to pharynx, sense of smell– Hair, mucus, blood capillaries, and ciliated epithelium that Hair, mucus, blood capillaries, and ciliated epithelium that

line the nasal cavity filter, moisten, warm, and eliminate line the nasal cavity filter, moisten, warm, and eliminate debris from the passing air (prevents respiratory debris from the passing air (prevents respiratory infections).infections).

Ethmoid bone

Parts ContinuedParts Continued PharynxPharynx – throat, posterior to nasal cavity – throat, posterior to nasal cavity

-passageway of food moving from oral cavity to -passageway of food moving from oral cavity to esophagusesophagus

-passageway of air moving between nasal cavity -passageway of air moving between nasal cavity and larynxand larynx

Parts ContinuedParts Continued LarynxLarynx – passageway for air moving in and out of – passageway for air moving in and out of

trachea (superior to trachea), prevents foreign trachea (superior to trachea), prevents foreign objects from entering tracheaobjects from entering trachea– 8 rings of cartilage and the mucous membrane 8 rings of cartilage and the mucous membrane

has 2 pairs of foldshas 2 pairs of folds– Houses vocal cords “voice box” – vibrate for Houses vocal cords “voice box” – vibrate for

speechspeech

Laryngitis - vocal cords swell, they vibrate differently, leading to hoarseness.Nodules - benign non-cancerous growths on the vocal cords are most often caused by voice misuse or overuseleading to hoarseness.Acid reflux – inflammation, redness, can lead to a sore or even laryngeal cancer if untreated.

Parts ContinuedParts Continued Thyroid cartilage Thyroid cartilage – big piece of shield-shaped – big piece of shield-shaped

cartilage in front of the larynx (Adam’s apple) – cartilage in front of the larynx (Adam’s apple) – males onlymales only

EpiglottisEpiglottis – flap of cartilage that closes off the – flap of cartilage that closes off the larynx when swallowing so that food goes down larynx when swallowing so that food goes down the esophagus and not to the lungs (if anything the esophagus and not to the lungs (if anything but air enters the larynx – it causes us to but air enters the larynx – it causes us to cough)cough)

Parts ContinuedParts Continued TracheaTrachea – windpipe (1” wide & 4” long), splits into – windpipe (1” wide & 4” long), splits into

L & R bronchi L & R bronchi – – lined with ciliated mucous membrane to sweep lined with ciliated mucous membrane to sweep debris away from lungs towards pharynx, debris away from lungs towards pharynx, reinforced with cartilage rings to keep it open reinforced with cartilage rings to keep it open (snaps shut when hit)(snaps shut when hit)

TracheaTrachea blockage of tracheablockage of trachea

– heimlich maneuverheimlich maneuver– blockage causes asphyxiation in blockage causes asphyxiation in

minutes minutes tracheostomy tracheostomy

Parts ContinuedParts Continued BronchiBronchi – trachea divides into 2 to go to – trachea divides into 2 to go to

each lungeach lung Bronchioles or bronchial tree Bronchioles or bronchial tree – smaller and – smaller and

smaller branches that end with alveolismaller branches that end with alveoli– Branching increases surface area to absorb Branching increases surface area to absorb

more O2 (lungs are small but each have more O2 (lungs are small but each have surface area the size of a tennis court).surface area the size of a tennis court).

AsthmaAsthma

Parts ContinuedParts Continued AlveoliAlveoli – air sacs lined with epithelium – air sacs lined with epithelium LungsLungs – most of the lungs are made of the – most of the lungs are made of the

alveoli (300 million) held together with alveoli (300 million) held together with connective tissueconnective tissue– Left lung – 2 lobes/ Right lung – 3 lobesLeft lung – 2 lobes/ Right lung – 3 lobes– Covered by serous membrane (pleura) – keep Covered by serous membrane (pleura) – keep

the lungs from rubbing against the thoracic the lungs from rubbing against the thoracic cavity and adhere lungs to the chest wall for cavity and adhere lungs to the chest wall for inflation during breathinginflation during breathing

AlveoliAlveoli Movement of material happens from the alveoli Movement of material happens from the alveoli

to the capillaries by simple diffusion (oxygen to the capillaries by simple diffusion (oxygen enters the capillaries and carbon dioxide leaves enters the capillaries and carbon dioxide leaves them and enters the alveoli)them and enters the alveoli)

Macrophages move in and out and destroy Macrophages move in and out and destroy bacteria that get inbacteria that get in– Air is one way in – debris, smoke, pollutants, etc. Air is one way in – debris, smoke, pollutants, etc.

needs to be eliminatedneeds to be eliminated Embedded in the epithelial cells are cells that Embedded in the epithelial cells are cells that

make lung make lung surfactantsurfactant – lipid coating that keeps – lipid coating that keeps alveoli from collapsingalveoli from collapsing– ““Wind knocked out of you”Wind knocked out of you”

Surface area for gas exchange of each lung (300 Surface area for gas exchange of each lung (300 million alveoli) is about the size of 1 tennis courtmillion alveoli) is about the size of 1 tennis court

Alveoli

DiaphragmDiaphragm DiaphragmDiaphragm controls breathing, not lungs controls breathing, not lungs

– Muscle controlled by brain (passive process Muscle controlled by brain (passive process when sitting)when sitting)

When relaxed, diaphragm is curved upward and When relaxed, diaphragm is curved upward and when contracted, it flattens out.when contracted, it flattens out.

Diaphragm and BreathingDiaphragm and Breathing Lungs respond to air pressure differences within Lungs respond to air pressure differences within

thoracic cavitythoracic cavity Inhalation:Inhalation:

– Diaphragm contracts (flattens), the volume in the Diaphragm contracts (flattens), the volume in the thoracic cavity increases so the pressure decreasesthoracic cavity increases so the pressure decreases

– Atmospheric pressure is higher than the pressure in the Atmospheric pressure is higher than the pressure in the thoracic cavity so it automatically flows inthoracic cavity so it automatically flows in

– Intercostal muscles also expand the ribs aiding in lung Intercostal muscles also expand the ribs aiding in lung expansion and the decrease in pressure (lungs adhere to expansion and the decrease in pressure (lungs adhere to the thoracic wall by the pleural membrane)the thoracic wall by the pleural membrane)

Diaphragm and BreathingDiaphragm and Breathing Lungs respond to air pressure differences within Lungs respond to air pressure differences within

thoracic cavitythoracic cavity Exhalation:Exhalation:

– Diaphragm relaxes (moves upward), the volume in the Diaphragm relaxes (moves upward), the volume in the thoracic cavity decreases so the pressure increasesthoracic cavity decreases so the pressure increases

– Atmospheric pressure is lower than the pressure in the Atmospheric pressure is lower than the pressure in the thoracic cavity so it automatically flows outthoracic cavity so it automatically flows out

Volume inc, pressure dec, air enters Volume dec, pressure inc, air exits

Breathing ContinuedBreathing Continued Tidal VolumeTidal Volume – volume of air inhaled and – volume of air inhaled and

exhaled (500 mls/1pt.)exhaled (500 mls/1pt.) Inspiratory Reserve VolumeInspiratory Reserve Volume – amount that can – amount that can

forcibly be taken in over tidal volume (2000-3000 forcibly be taken in over tidal volume (2000-3000 mls)mls)

Vital capacityVital capacity – Maximum air the lungs can hold – Maximum air the lungs can hold (4500 mls)(4500 mls)

Expiratory Reserve VolumeExpiratory Reserve Volume – amount that can – amount that can be forcibly exhaled after tidal expiration (about be forcibly exhaled after tidal expiration (about 1000 mls)1000 mls)

Residual VolumeResidual Volume – amount of air left in the – amount of air left in the lungs even after forced expiration (about 1000 lungs even after forced expiration (about 1000 mls) – allow gas exchange between breaths and mls) – allow gas exchange between breaths and keeps alveoli inflatedkeeps alveoli inflated– Lose this when getting the “wind knocked out of you”Lose this when getting the “wind knocked out of you”

Sneezing and coughing clear the air passages of Sneezing and coughing clear the air passages of debris and excess mucousdebris and excess mucous

Gas ExchangeGas Exchange Oxygen diffuses from inside the Oxygen diffuses from inside the

alveoli (20%) to the capillaries of the alveoli (20%) to the capillaries of the lungs (~0%)lungs (~0%)

Most of it is picked up by hemoglobinMost of it is picked up by hemoglobin After the blood is pumped to the After the blood is pumped to the

body and reaches the capillaries of body and reaches the capillaries of the body’s tissues – the oxygen is the body’s tissues – the oxygen is dumped off by hemoglobin and dumped off by hemoglobin and diffuses out of the RBC into the diffuses out of the RBC into the interstitial fluid surrounding the cellsinterstitial fluid surrounding the cells

It then diffuses into the cellsIt then diffuses into the cells

How does more Oxygen Get to the How does more Oxygen Get to the Cells that Need it the Most?Cells that Need it the Most?

i.e. cells doing the most worki.e. cells doing the most work1.1. Blood is diverted to the most active areas Blood is diverted to the most active areas

(precap. sphincters shut off blood to certain areas (precap. sphincters shut off blood to certain areas not in use)not in use)

-upper body workout vs. lower body-upper body workout vs. lower body

-don’t swim for an hour after you eat-don’t swim for an hour after you eat

2.2. Hemoglobin drops off OHemoglobin drops off O2 2 quicker in areas of low Oquicker in areas of low O2 2

and high COand high CO2 2 (higher acidity) and holds onto it in (higher acidity) and holds onto it in reverse situations.reverse situations.

3.3. The higher the concentration difference of oxygen The higher the concentration difference of oxygen between blood and cells, the faster the rate of between blood and cells, the faster the rate of diffusiondiffusion

Control of RespirationControl of Respiration Controlled by the autonomic nervous system Controlled by the autonomic nervous system Normally breath 12-15 times/minuteNormally breath 12-15 times/minute Do have some conscious control over breathing Do have some conscious control over breathing

but autonomic centers will ignore information if but autonomic centers will ignore information if ph of blood is low (can’t hold your breath until ph of blood is low (can’t hold your breath until you die)you die)

Mostly controlled by level of carbon dioxide in the Mostly controlled by level of carbon dioxide in the blood (pH) – act on the medulla oblongata in the blood (pH) – act on the medulla oblongata in the brainbrain

Oxygen concentration is also measured in the Oxygen concentration is also measured in the aorta and carotid arteries which send signals to aorta and carotid arteries which send signals to the medulla – only when oxygen is dangerously the medulla – only when oxygen is dangerously lowlow

Hyperventilating – breathing real fast – lose too Hyperventilating – breathing real fast – lose too much carbon dioxide too fast, blood becomes a much carbon dioxide too fast, blood becomes a little basic and breathing may stop – breath into a little basic and breathing may stop – breath into a bag to increase carbon dioxide levelsbag to increase carbon dioxide levels

Effects of Cigarette SmokeEffects of Cigarette Smoke Healthy resp syst is continuously cleansed by Healthy resp syst is continuously cleansed by

mucus trapping dirt and pathogens, cilia then mucus trapping dirt and pathogens, cilia then sweeps towards mouthsweeps towards mouth

With the first inhalation of smoke, cilia slows. With the first inhalation of smoke, cilia slows. Eventually become paralyzed and disappear – Eventually become paralyzed and disappear – leads to “smokers cough”leads to “smokers cough”– Lethal chain reaction – cough Lethal chain reaction – cough chronic bronchitischronic bronchitis

inc. mucus production and bronchial thickening inc. mucus production and bronchial thickening bronchioles lose elasticity bronchioles lose elasticity inc. air pressure in alveoli inc. air pressure in alveoli and can rupture = smoking induced and can rupture = smoking induced emphysemaemphysema

– Cellular changes can occur as well leading to lung Cellular changes can occur as well leading to lung cancer. 80% of lung cancer cases are due to cigarette cancer. 80% of lung cancer cases are due to cigarette smoking.smoking.

COPD stands for COPD stands for chronic obstructive pulmonary diseasechronic obstructive pulmonary disease and it is a and it is a serious lung disease that makes it harder and harder to breathe. Both serious lung disease that makes it harder and harder to breathe. Both

chronic bronchitis and emphysema are considered to be COPD.chronic bronchitis and emphysema are considered to be COPD.

Picture of Alveoli ruptured as a result of emphysema

ReferencesReferences

http://www.cliffsnotes.com/http://www.cliffsnotes.com/study_guide/Function-of-the-study_guide/Function-of-the-Respiratory-System.topicArticleId-Respiratory-System.topicArticleId-277792,articleId-277729.html277792,articleId-277729.html