THE RESPIRATORY THE RESPIRATORY SYSTEMSYSTEM

THE HUMAN RESPIRATORY SYSTEMTHE HUMAN RESPIRATORY SYSTEM

Organs of theRespiratory System

1. Nose2. Pharynx3. Larynx4. Trachea5. Bronchi6. Alveoli 7. Lungs (Pleura)

Function of the Respiratory SystemFunction of the Respiratory System

Oversees gas exchanges between the blood Oversees gas exchanges between the blood and external environmentand external environment

Exchange of gasses takes place within the Exchange of gasses takes place within the lungs in the alveolilungs in the alveoli

Passageways to the lungs purify, warm, and Passageways to the lungs purify, warm, and humidify the incoming airhumidify the incoming air

Organs of the Respiratory SystemOrgans of the Respiratory System

Upper Respiratory SystemUpper Respiratory System

1. The Nose1. The Nose The only externally visible part of The only externally visible part of

the respiratory systemthe respiratory system Air enters the nose through the Air enters the nose through the

external nares (nostrils)external nares (nostrils) The interior of the nose consists The interior of the nose consists

of a nasal cavity divided by a of a nasal cavity divided by a nasal septumnasal septum

Warms, moistens, and filters airWarms, moistens, and filters air2. Pharynx2. Pharynx Muscular passage from nasal Muscular passage from nasal

cavity to larynxcavity to larynx

3. Larynx3. Larynx Plays a role in speech (vocal cords)Plays a role in speech (vocal cords)

Vibrate with expelled air to create sound (speech)Vibrate with expelled air to create sound (speech)

Glottis – opening between vocal cordsGlottis – opening between vocal cords

4. Epiglottis4. Epiglottis Spoon-shaped flap of elastic cartilage Spoon-shaped flap of elastic cartilage

Superior opening of the larynxSuperior opening of the larynx Routes food to the esophagus and air toward the Routes food to the esophagus and air toward the

tracheatrachea

Action of the epiglottis

5. Trachea5. Trachea Connects larynx with bronchiConnects larynx with bronchi Made of eight rigid hyaline cartilages Made of eight rigid hyaline cartilages

Thyroid cartilage is the largest hyaline cartilageThyroid cartilage is the largest hyaline cartilage Protrudes anteriorly (Adam’s apple)Protrudes anteriorly (Adam’s apple)

Lined with ciliated mucosaLined with ciliated mucosa Beat continuously in the opposite direction of incoming airBeat continuously in the opposite direction of incoming air Expel mucus loaded with dust and other debris away from Expel mucus loaded with dust and other debris away from

lungslungs Walls are reinforced with C-shaped hyaline cartilageWalls are reinforced with C-shaped hyaline cartilage

Upper Respiratory SystemUpper Respiratory System

The Lower Respiratory SystemThe Lower Respiratory System

6. 6. BronchiBronchi Formed by division of the tracheaFormed by division of the trachea Enters the lung at the hilus (medial Enters the lung at the hilus (medial

depression)depression) Right bronchus is wider, shorter, and Right bronchus is wider, shorter, and

straighter than leftstraighter than left Bronchi subdivide into smaller and Bronchi subdivide into smaller and

smaller branchessmaller branches77. Bronchioles. Bronchioles Smallest branches of the bronchiSmallest branches of the bronchi All but the smallest branches have All but the smallest branches have

reinforcing cartilagereinforcing cartilage Terminal bronchioles end in alveoliTerminal bronchioles end in alveoli

The Lower Respiratory SystemThe Lower Respiratory System8.8. AlveoliAlveoli Gas exchange takes place within the Gas exchange takes place within the

alveoli in the respiratory membranealveoli in the respiratory membrane Thin cellular layer lining alveolar Thin cellular layer lining alveolar

wallswalls Pulmonary capillaries cover external Pulmonary capillaries cover external

surfaces of alveolisurfaces of alveoli9. Lungs9. Lungs Occupy most of the thoracic cavityOccupy most of the thoracic cavity

Apex is near the clavicle (superior Apex is near the clavicle (superior portion)portion)

Base rests on the diaphragm Base rests on the diaphragm (inferior portion)(inferior portion)

Each lung is divided into lobes by Each lung is divided into lobes by fissuresfissures

Left lung – two lobesLeft lung – two lobes Right lung – three lobesRight lung – three lobes

The Lower Respiratory SystemThe Lower Respiratory System

10. PleuraPulmonary (visceral) pleura covers the lung surface

Gas ExchangeGas Exchange

Gas crosses the respiratory membrane by Gas crosses the respiratory membrane by diffusiondiffusion

Oxygen enters the bloodOxygen enters the blood Carbon dioxide enters the alveoliCarbon dioxide enters the alveoli

Complete the Lab

Anatomy of the Respiratory System

Events of RespirationEvents of Respiration

Events of RespirationEvents of Respiration

Pulmonary ventilation: Pulmonary ventilation: air in and out of the air in and out of the lungslungs

External respiration: External respiration: gas exchange between gas exchange between the alveoli and the bloodthe alveoli and the blood

Transport: Transport: oxygen and carbon dioxide being oxygen and carbon dioxide being transported to and from the body cellstransported to and from the body cells

Internal respiration: Internal respiration: gas exchange between gas exchange between the blood and the body cellsthe blood and the body cells

Events of RespirationEvents of Respiration

In more detailIn more detail

Pulmonary ventilation Pulmonary ventilation

Moving air in and out of the lungsMoving air in and out of the lungs

(breathing in and out)(breathing in and out)

We will further explore this in the sectionWe will further explore this in the section

““Mechanics of Breathing”Mechanics of Breathing”

External RespirationExternal Respiration

Exchange of gases between Exchange of gases between the alveoli of the the alveoli of the lungs and the capillaries of the blood streamlungs and the capillaries of the blood stream

External RespirationExternal Respiration

Oxygen movement into the bloodOxygen movement into the blood The alveoli always has more oxygen than the bloodThe alveoli always has more oxygen than the blood Oxygen moves by diffusion towards the area of lower Oxygen moves by diffusion towards the area of lower

concentrationconcentration Pulmonary capillary blood gains oxygenPulmonary capillary blood gains oxygen

Carbon dioxide movement out of the bloodCarbon dioxide movement out of the blood Blood returning from tissues has higher concentrations of Blood returning from tissues has higher concentrations of

carbon dioxide than air in the alveolicarbon dioxide than air in the alveoli Pulmonary capillary blood gives up carbon dioxidePulmonary capillary blood gives up carbon dioxide

Blood leaving the lungs is oxygen-rich and carbon Blood leaving the lungs is oxygen-rich and carbon dioxide-poordioxide-poor

External RespirationExternal Respiration

Gas Transport in the BloodGas Transport in the Blood Oxygen transport in the bloodOxygen transport in the blood

Inside red blood cells attached to Inside red blood cells attached to hemoglobin hemoglobin (oxyhemoglobin [HbO(oxyhemoglobin [HbO22])])

A small amount is carried dissolved in the plasmaA small amount is carried dissolved in the plasma Carbon dioxide transport in the bloodCarbon dioxide transport in the blood

Most is transported Most is transported in the plasmain the plasma as bicarbonate as bicarbonate ion (HCOion (HCO33–)–)

A small amount is carried inside red blood cells A small amount is carried inside red blood cells on hemoglobin, but at different binding sites than on hemoglobin, but at different binding sites than those of oxygenthose of oxygen

Gas Transport in the BloodGas Transport in the Blood

Internal RespirationInternal Respiration

Exchange of gases between Exchange of gases between the blood and the blood and body cellsbody cells

An opposite reaction to what occurs in the An opposite reaction to what occurs in the lungs (external respiration)lungs (external respiration) Carbon dioxide diffuses out of tissue to bloodCarbon dioxide diffuses out of tissue to blood Oxygen diffuses from blood into tissueOxygen diffuses from blood into tissue

Internal RespirationInternal Respiration

The Mechanics of Breathing The Mechanics of Breathing (Pulmonary ventilation)(Pulmonary ventilation)

see Figure 13.7 on pg 3 in your packetsee Figure 13.7 on pg 3 in your packet Completely mechanical processCompletely mechanical process Depends on volume changes in the thoracic Depends on volume changes in the thoracic

cavitycavity Volume changes lead to pressure changes, Volume changes lead to pressure changes,

which lead to the flow of gases to equalize which lead to the flow of gases to equalize pressurepressure

Two phasesTwo phases Inspiration – flow of air into lungInspiration – flow of air into lung Expiration – air leaving lungExpiration – air leaving lung

InspirationInspiration Diaphragm and intercostal muscles contract Diaphragm and intercostal muscles contract The size of the thoracic cavity increasesThe size of the thoracic cavity increases External air is pulled into the lungs due to an increase External air is pulled into the lungs due to an increase

in intrapulmonary volumein intrapulmonary volume

ExpirationExpiration Largely a passive process which depends on natural Largely a passive process which depends on natural

lung elasticitylung elasticity As muscles relax, air is pushed out of the lungsAs muscles relax, air is pushed out of the lungs Forced expiration can occur mostly by contracting Forced expiration can occur mostly by contracting

internal intercostal muscles to depress the rib cageinternal intercostal muscles to depress the rib cage

Pressure Differences in the Thoracic Pressure Differences in the Thoracic CavityCavity

Normal pressure within the pleural space is Normal pressure within the pleural space is always negative (intrapleural pressure)always negative (intrapleural pressure)

Differences in lung and pleural space Differences in lung and pleural space pressures keep lungs from collapsingpressures keep lungs from collapsing

External External Respiration, Respiration,

Gas Gas Transport, Transport,

and Internal and Internal Respiration Respiration SummarySummary

(page 5 in your packet)(page 5 in your packet)

Non-respiratory Air MovementsNon-respiratory Air Movements (not in your notes)(not in your notes)

Can be caused by reflexes or voluntary actionsCan be caused by reflexes or voluntary actions ExamplesExamples

Cough and sneeze – clears lungs of debrisCough and sneeze – clears lungs of debris LaughingLaughing CryingCrying YawnYawn HiccupHiccup

Respiratory SoundsRespiratory Sounds(not in your notes)(not in your notes)

Sounds are monitored with a stethoscopeSounds are monitored with a stethoscope Bronchial sounds – produced by air rushing Bronchial sounds – produced by air rushing

through trachea and bronchithrough trachea and bronchi Vesicular breathing sounds – soft sounds of air Vesicular breathing sounds – soft sounds of air

filling alveolifilling alveoli

Neural Regulation of RespirationNeural Regulation of Respiration(page 4 in your packet)(page 4 in your packet)

Activity of respiratory muscles is transmitted to the Activity of respiratory muscles is transmitted to the brain by brain by the phrenic and intercostal nervesthe phrenic and intercostal nerves

Neural centers that control rate and depth are located Neural centers that control rate and depth are located in in the medullathe medulla

The The ponspons appears to smooth out respiratory rate appears to smooth out respiratory rate Normal respiratory rate (eupnea) Normal respiratory rate (eupnea) is 12–15 is 12–15

respirations per minuterespirations per minute Hypernia is increased respiratory rate often due to Hypernia is increased respiratory rate often due to

extra oxygen needsextra oxygen needs

Factors Influencing Respiratory Rate Factors Influencing Respiratory Rate and Depthand Depth

Physical factorsPhysical factors Increased body temperatureIncreased body temperature ExerciseExercise TalkingTalking CoughingCoughing

Volition (conscious control)Volition (conscious control) Emotional factorsEmotional factors

Factors Influencing Respiratory Rate Factors Influencing Respiratory Rate and Depthand Depth

Chemical factors:Chemical factors:Carbon dioxide levelsCarbon dioxide levels Level of carbon dioxide in the blood is the main regulatory Level of carbon dioxide in the blood is the main regulatory

chemical for respirationchemical for respiration Increased carbon dioxide increases respirationIncreased carbon dioxide increases respiration Changes in carbon dioxide act directly on the medulla Changes in carbon dioxide act directly on the medulla

oblongataoblongata

Oxygen levelsOxygen levels Changes in oxygen concentration in the blood are detected by Changes in oxygen concentration in the blood are detected by

chemoreceptors in the aorta and carotid arterychemoreceptors in the aorta and carotid artery Information is sent to the medulla oblongataInformation is sent to the medulla oblongata

Respiratory Rate Changes Respiratory Rate Changes throughout Lifethroughout Life

Newborns – Newborns – 40 to 8040 to 80 respirations per minute respirations per minute Infants – Infants – 3030 respirations per minute respirations per minute Age 5 – Age 5 – 2525 respirations per minute respirations per minute Adults – Adults – 12 to 1812 to 18 respirations per minute respirations per minute Rate often increases somewhat with old ageRate often increases somewhat with old age

Aging EffectsAging Effects

Elasticity of lungs decreasesElasticity of lungs decreases Vital capacity decreasesVital capacity decreases Blood oxygen levels decreaseBlood oxygen levels decrease Stimulating effects of carbon dioxide Stimulating effects of carbon dioxide

decreasesdecreases More risks of respiratory tract infectionMore risks of respiratory tract infection

Developmental Aspects of the Developmental Aspects of the Respiratory SystemRespiratory System

(not in your notes)(not in your notes) Lungs are filled with fluid in the fetusLungs are filled with fluid in the fetus Lungs are not fully inflated with air until two weeks Lungs are not fully inflated with air until two weeks

after birthafter birth Surfactant that lowers alveolar surface tension is not Surfactant that lowers alveolar surface tension is not

present until late in fetal development and may not be present until late in fetal development and may not be present in premature babiespresent in premature babies

Important birth defectsImportant birth defects Cystic fibrosis – over secretion of thick mucus clogs the Cystic fibrosis – over secretion of thick mucus clogs the

respiratory systemrespiratory system Cleft palateCleft palate

Complete the Lab

Respiratory System Physiology

Respiratory Vocabulary

Eupnea = normal breathing rate

Hypernea = abnormal breathing

Dyspnea = difficult or labored breathing

Apnea = cessation of (stopped) breathing

Respiratory Volumes Respiratory Volumes andand

CapacitiesCapacities

(Page 3 in your packet)

Tidal volume [TV]Tidal volume [TV]

Normal breathing moves Normal breathing moves about 500 ml of air with about 500 ml of air with each breath each breath

Many factors that affect Many factors that affect respiratory capacityrespiratory capacity A person’s sizeA person’s size SexSex AgeAge Physical conditionPhysical condition

Inspiratory reserve volume (IRV)Inspiratory reserve volume (IRV)

Amount of air that can be taken in forcibly Amount of air that can be taken in forcibly over the tidal volumeover the tidal volume

Usually between 2100ml and 3200 mlUsually between 2100ml and 3200 ml

Expiratory reserve volume (ERV)Expiratory reserve volume (ERV)

Amount of air that can be forcibly exhaledAmount of air that can be forcibly exhaled Approximately 1200 mlApproximately 1200 ml

Residual volumeResidual volume

Air remaining in lung after expirationAir remaining in lung after expiration About 1200 mlAbout 1200 ml

Vital capacityVital capacity The total amount of exchangeable airThe total amount of exchangeable air

Vital capacity = TV + IRV + ERVVital capacity = TV + IRV + ERV Dead space volumeDead space volume

Air that remains in conducting zone and never Air that remains in conducting zone and never reaches alveolireaches alveoli

About 150 mlAbout 150 ml

Respiratory Volumes Respiratory Volumes andand

CapacitiesCapacities

Complete the Lab

Spirometry in Respiratory Function

Respiratory DisordersRespiratory Disorders

Chronic Obstructive Pulmonary Chronic Obstructive Pulmonary Disease (COPD)Disease (COPD)

Exemplified by chronic bronchitis and emphysemaExemplified by chronic bronchitis and emphysema Major causes of death and disability in the United Major causes of death and disability in the United

StatesStates Features of these diseasesFeatures of these diseases

Patients almost always have a history of smokingPatients almost always have a history of smoking Labored breathing (dyspnea) becomes progressively more Labored breathing (dyspnea) becomes progressively more

severesevere Coughing and frequent pulmonary infections are commonCoughing and frequent pulmonary infections are common Most victims retain carbon dioxide, are hypoxic and have Most victims retain carbon dioxide, are hypoxic and have

respiratory acidosisrespiratory acidosis Those infected will ultimately develop respiratory failureThose infected will ultimately develop respiratory failure

EmphysemaEmphysema

Alveoli enlarge as adjacent chambers break Alveoli enlarge as adjacent chambers break throughthrough

Chronic inflammation promotes lung fibrosisChronic inflammation promotes lung fibrosis Airways collapse during expirationAirways collapse during expiration Patients use a large amount of energy to exhalePatients use a large amount of energy to exhale Over inflation of the lungs leads to a Over inflation of the lungs leads to a

permanently expanded barrel chestpermanently expanded barrel chest Cyanosis appears late in the diseaseCyanosis appears late in the disease

An emphysema lungAn emphysema lung

Chronic BronchitisChronic Bronchitis

Mucosa of the lower respiratory passages Mucosa of the lower respiratory passages becomes severely inflamedbecomes severely inflamed

Mucus production increasesMucus production increases Pooled mucus impairs ventilation and gas Pooled mucus impairs ventilation and gas

exchangeexchange Risk of lung infection increasesRisk of lung infection increases Pneumonia is commonPneumonia is common Hypoxia and cyanosis occur earlyHypoxia and cyanosis occur early

Chronic BronchitisChronic Bronchitis

Lung CancerLung Cancer

Accounts for 1/3 of all cancer deaths in the Accounts for 1/3 of all cancer deaths in the United StatesUnited States

Increased incidence associated with smokingIncreased incidence associated with smoking Three common typesThree common types

Squamous cell carcinomaSquamous cell carcinoma AdenocarcinomaAdenocarcinoma Small cell carcinomaSmall cell carcinoma

Lung CancerLung Cancer

Sudden Infant Death syndrome Sudden Infant Death syndrome (SIDS)(SIDS)

Apparently healthy infant stops breathing and Apparently healthy infant stops breathing and dies during sleepdies during sleep

Some cases are thought to be a problem of the Some cases are thought to be a problem of the neural respiratory control centerneural respiratory control center

One third of cases appear to be due to heart One third of cases appear to be due to heart rhythm abnormalitiesrhythm abnormalities

AsthmaAsthma

Chronic inflamed hypersensitive bronchiole Chronic inflamed hypersensitive bronchiole passagespassages

Response to irritants with dyspnea, coughing, Response to irritants with dyspnea, coughing, and wheezingand wheezing

Treated with medications and inhalersTreated with medications and inhalers

AsthmaAsthma

Cystic FibrosisCystic Fibrosis

Most common lethal genetic diseaseMost common lethal genetic disease Thick mucus production causes problems with Thick mucus production causes problems with

breathing and digestionbreathing and digestion Salty sweat (diagnosed with a sweat test)Salty sweat (diagnosed with a sweat test)

Cystic FibrosisCystic Fibrosis

In people with cystic fibrosis, mucus in the airways is thicker than normal. The body also produces more mucus, and mucus tends to build up. The result is obstruction of airways—which makes breathing difficult—and the creation of an environment for infection-causing bacteria to grow.

PneumoniaPneumonia

Infection in the lungsInfection in the lungs Caused byCaused by

Bacteria (treatable with antibiotics)Bacteria (treatable with antibiotics) VirusVirus fungusfungus

PneumoniaPneumonia

Whooping CoughWhooping Cough

Also called percussisAlso called percussis Cough with a whooping soundCough with a whooping sound Cough so hard that a person Cough so hard that a person

vomits, can’t catch his breath, vomits, can’t catch his breath, or even turns blueor even turns blue

Children are now immunized Children are now immunized for this diseasefor this disease

http://www.whoopingcough.net/symptoms.htm

TuberculosisTuberculosis

Commonly called TBCommonly called TB Caused by a bacteria that usually attacks the Caused by a bacteria that usually attacks the

lungs – the bacteria will destroy tissuelungs – the bacteria will destroy tissue Spread from one person to another by airSpread from one person to another by air Skin test for the presence of the bacteriaSkin test for the presence of the bacteria

TuberculosisTuberculosis Latent TBLatent TB – persons who have the bacteria – persons who have the bacteria

but do not get sick (they do not spread it, but but do not get sick (they do not spread it, but they may become sick later)they may become sick later)

Active TB -Active TB - symptoms include symptoms include Bad cough lasting 3 weeks or longerBad cough lasting 3 weeks or longer Pain in chestPain in chest Coughing up bloodCoughing up blood Weakness or fatigueWeakness or fatigue Loss of appetite – weight lossLoss of appetite – weight loss Chills and feverChills and fever Night sweatsNight sweats