Answers

Respiratory SystemPulmonary Ventilation• Movement of air in & out of the lungs4 stages External respiration• Gas exchange between blood & airGas transport in blood between lungs and body cellsInternal respiration• Gas exchange between blood & body cellsCellular respiration• Utilization of the oxygen by mitochondria

Upper Respiratory Tract

• Nose

• Nasal cavity

• Paranasal sinuses

• Pharynx

Lower Respiratory Tract

• Larynx

• Trachea

• Bronchial tree

• Lungs

NoseInternal support• bone and cartilageNostrils• openings through which air can enter and

leaveInternal hairs• guard entrance to nostrils

Nasal Cavity

Hollow space behind the noseNasal septum• bone and cartilage• divide the cavity into right and

left portionsNasal conchae• bones that divide the cavity into

passageways• support and increase SA of the

mucus membrane

Nasal CavityMucous Membrane

• many blood vessels (warm and vaporize air)

• sticky mucus to filter air

Cilia

• move mucus and trapped particles to pharynx to be swallowed

Why is mouth breathing a problem? Why would someone breathe through their mouth?

Paranasal SinusesAir filled spaces• maxillary, ethmoid, sphenoid,

and frontal bonesLined with mucous membranesReduce weight of skullResonance for voiceSinus infection• blockage from infection or

allergic reaction

PharynxThroatBehind oral cavityBetween nasal cavity & larynxPassageway for air to tracheaPassageway for food to esophagusHelps produce sounds of speechSubdivisons• nasopharynx, oropharynx,

laryngopharynx

LarynxEnlargement in the trachea• Voice, airway, ensure food goes into esophagusCartilages (hyaline)• thyroid, cricoid, epiglottic Vocal cords• false (upper) & true (lower)Glottis • Slit between vocal cords Epiglottis• Elastic cartilage• Covers trachea during swallowing

Laryngitis• Inflammation of the vocal cords• Virus, bacteria, overuse

Normal

TracheaIn front of the esophagus

Many goblet cells and cilia

Tracheal wall• not collapsible• hyaline cartilage rings on the

anterior wall of the trachea (not on the back to bolus can travel down esophagus)

Bronchial Tree • Branched airways from the

trachea to the air sacs in the lungs

• R & L primary bronchi

• Bronchioles• Alveolar ducts• Alveolar sacs

• Alveoli

– small microscopic air sacs

Bronchitis is the inflammation of the bronchi, the main air passages to the lungs, it generally follows a viral respiratory infection. Symptoms include; coughing, shortness of breath, wheezing and fatigue.

LungsSoft and spongyRight lung is larger (3 lobes)Bronchus and vessels suspend the

lungVisceral pleuraParietal pleuraPleural cavity• potential space between visceral

and parietal pleura

Pneumonia is an inflammation of the lung that is most often caused by infection with bacteria, viruses, or other organisms. Occasionally, inhaled chemicals that irritate the lungs can cause pneumonia. Healthy people can usually fight off pneumonia infections. However, people who are sick, including those who are recovering from the flu (influenza) or an upper respiratory illness, have weakened immune systems that make it easier for bacteria to grow in their lungs.

Respiratory System

InspirationAtmospheric pressure• force that pushes air into lungsSurface tension• difficult to inflate alveoli and may cause them to collapseSurfactant• lipid that prevents alveoli from collapsing• respiratory distress syndrome

– Not produced until 36 wks. Gestation– Ventilator and artificial surfactant

             

Respiratory Distress Syndrome (RDS) is a clinical diagnosis but one which is often interchanged with the terms Hyaline Membrane Disease (a pathological diagnosis) and Surfactant Deficiency (a term describing the typical appearances on radiographs of infants with RDS).

ExpirationExhaling – removing air

from alveoli

Forces

• elastic recoil of tissues &

• surface tension

Pneumothorax•occurs when all or part of a lung collapses or caves inward. This occurs when air gets in the area between the lung and chest wall. When this happens the lung cannot fill up with air, breathing becomes hard, and the body gets less oxygen. A collapsed lung can occur spontaneously in a healthy person or in someone who has lungs compromised by trauma,

asthma, bronchitis, or emphysema.

Expiration

Respiratory Cycle

Emphysema• Progressive, degenerative disease that destroys

alveolar walls

• Small air sacs merge– loss of SA

• Elasticity is lost– difficult to force air out

• Inherited enzyme deficiency or exposure to irritants

Emphysema is a lung disease involving damage to the air sacs (alveoli).There is progressive destruction of alveoli and the surrounding tissue that supports the alveoli. With more advanced disease, large air cysts develop where normal lung tissue used to be. Air is trapped in the lungs due to lack of supportive tissue which decreases oxygenation.

Lung CancerPrimary pulmonary cancers

• originate in the lungs

Bronchogenic carcinoma

• most common form

Difficult to control

• survival rate is low

May spread quickly

Nonrespiratory MovementsCoughing• force air upward against closure• clears lower respiratory passagesSneeze• clears upper respiratory passagesLaughing• releasing breath in short expirations

Nonrespiratory MovementsCrying

• similar to laughing

Hiccup

• sudden inspiration

• spasmodic contraction of the diaphragm while glottis is closed

Hiccups occur when a spasm contracts the diaphragm, causing an intake of breath that is suddenly stopped by the closure of the vocal cords (glottis).

Nonrespiratory Movements

Yawning

• aid respiration by causing a deep breath

•The Physiological Theory -- Our bodies induce yawning to drawn in more oxygen or remove a build-up of carbon dioxide. This theory helps explain why we yawn in groups. Larger groups produce more carbon dioxide, which means our bodies would act to draw in more oxygen and get rid of the excess carbon dioxide. However, if our bodies make us yawn to drawn in needed oxygen, wouldn't we yawn during exercise?

•The Evolution Theory -- Some think that yawning is something that began with our ancestors, who used yawning to show their teeth and intimidate others. An offshoot of this theory is the idea that yawning developed from early man as a signal for us to change activities.

•The Boredom Theory -- In the dictionary, yawning is said to be caused by boredom, fatigue or drowsiness. Although we do tend to yawn when bored or tired, this theory doesn't explain why Olympic athletes yawn right before they compete in their event. It's doubtful that they are bored with the world watching them.

http://health.howstuffworks.com/question5721.htm

http://health.howstuffworks.com/question5721.htm

•The average yawn lasts about six seconds.

•Your heart rate can rise as much as 30 percent during a yawn.

•55 percent of people will yawn within five minutes of seeing someone else yawn.

•Blind people yawn more after hearing an audio tape of people yawning.

•Reading about yawning will make you yawn.

•Olympic athletes often yawn before competition.

Interesting Yawning Facts

   

Respiratory Air VolumesSpirometry

• measures air volume

Respiratory cycle

• one inspiration + one expiration

Tidal volume (respiratory volume)

• amount of air that enters (or leaves) during a single cycle

Respiratory Air Volumes

Inspiratory reserve volume• complemented airExpiratory reserve volume• supplemental airResidual volume• air that remains in the lungs after

expiration• Allows for continual gas exchange

Respiratory Air CapacitiesVital capacity• max. amount of air that can be

expiredInspiratory capacity• max. amount of air that can be

inhaledFunctional residual capacity• volume of air that remains in

the lungs following expiration

Respiratory Air CapacitiesTotal lung capacity• varies with age, sex, and sizeDead space volume• Air in respiratory passages that does NOT contribute

to gas exchange

Respiratory CenterPons and medulla

Rhythmicity center in medulla

• controls basic rhythm of inspiration

Pneumotixic area of pons

• controls breathing rate

Factors Affecting BreathingLow blood oxygen has little direct

effectEmotional upset

Increased CO2 is the stimulusHyperventilation• Voluntary, rapid and deep breathing• lowers blood CO2 levels• Allows breath to be held for longer

periods of time (scuba divers)

Oxygen TransportOxyhemoglobin

Factors that release O2 from hemoglobin• Carbon dioxide increases• pH lowers• Temp. increasesHypoxia• deficiency of O2 reaching the tissues• Decreased bp, anemia, inadequate blood flow,

defect at cellular level (cyanide poisoning)

Carbon Dioxide Transport

Blood transports CO2

• dissolved in plasma– Bicarbonate ions (most common)

• Carbaminohemoglobin

• In HIGH concentrations can convert to carbonic acid