Respiratory Systems

Respiratory SystemPulmonary Ventilation• Movement of air in & out of the

lungs• System functions to inhale and

exhale air in order to absorb oxygen and expel carbon dioxide

4 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

Nose

Internal support

• bone and cartilage

Nostrils

• openings through which air can enter and leave

Internal hairs

• guard entrance to nostrils

Nasal CavityHollow space behind the nose

Nasal septum

• bone and cartilage

• divide the cavity into right and left portions

Nasal conchae

• bones that divide the cavity into passageways

• support and increase SA of the mucus membrane

Nasal Cavity - continuedMucous Membrane• many blood vessels (warm and vaporize

air)• sticky mucus to filter airCilia• move mucus and trapped particles to

pharynx to be swallowedWhy is mouth breathing a problem? Why

would someone breathe through their mouth?

Paranasal Sinuses

Air filled spaces

• maxillary, ethmoid, sphenoid, and frontal bones

Lined with mucous membranes

Reduce weight of skull

Resonance for voice

Sinus infection (sinusitis)

• blockage from infection or allergic reaction

PharynxThroat

Behind oral cavity

Between nasal cavity & larynx

Passageway

• Air and food

Sounds of speech

Subdivisons act as passageways

• Nasopharynx

• Oropharynx

• Laryngopharynx

LarynxEnlargement in the trachea• Voice, airway, ensure food goes into esophagusCartilages (hyaline) - thyroid, cricoid, epiglotticVocal cords• false (upper) & true (lower)Glottis • Slit between vocal cords • Closes when swallowingEpiglottis• 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

• Why are they not on the posterior side?

Bronchial Tree

• Branched airways from the trachea to the air sacs in the lungs

• R & L primary bronchi• Chronic bronchitis results from increased

mucus production; promotes coughing

• Bronchioles• Affected by asthma where the bronchial

tree narrows and wheezing/difficulty breathing occurs

• 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.

Lungs

Soft and spongy

Right lung is larger (3 lobes)

Bronchus and vessels suspend the lung

Visceral pleura

Parietal pleura

Pleural cavity

• potential space between visceral and parietal pleura

Tuberculosis

• Lung infection

• Bacterial

• On this rise since 1985

• Most strains are resistant so must be treated with array of meds and over a lengthy time period

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.

InspirationEupnea

• Normal breathing in reference to rate and depth

–Apnea - cessation of breathing

–Dyspnea – labored breathing

Atmospheric pressure

• force that pushes air into lungs

Surface tension

• difficult to inflate alveoli and may cause them to collapse

Surfactant

• lipid that prevents alveoli from collapsing

• respiratory distress syndrome (RDS)

• Not produced until 36 wks. Gestation

• Ventilator and artificial surfactant

Hypoxia

• Chronic oxygen deficiency

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).

Expiration

Exhaling – 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.

Pulmonary Ventilation

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

• COPD–Emphysema + chronic

bronchitis

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 Cancer

Primary pulmonary cancers

•originate in the lungs

Bronchogenic carcinoma

•most common form

Difficult to control

• survival rate is low

May spread quickly

Nonrespiratory Movements

Coughing• force air upward against closure• clears lower respiratory passages

Sneeze• clears upper respiratory passages

Laughing• releasing breath in short expirations

Crying• similar to laughing

Nonrespiratory Movements

Hiccup

• sudden inspiration

• spasmodic contraction of the diaphragm while glottis is closed

Yawning

• aid respiration by causing a deep breath

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).

•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

Inspiratory reserve volume

• complemented air

Expiratory reserve volume

• supplemental air

Residual volume

• air that remains in the lungs after expiration

• Allows for continual gas exchange

Respiratory Air Capacities

Vital 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

Total 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 effect

Emotional upset

Increased CO2 is the stimulus

Hyperventilation

• 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. increases

Hypoxia

• deficiency of O2 reaching the tissues

• Decreased bp, anemia, inadequate blood flow, defect at cellular level (cyanide poisoning)

Carbon Dioxide TransportBlood transports CO2

• dissolved in plasma

– Bicarbonate ions (most common)

• Carbaminohemoglobin

• In HIGH concentrations can convert to carbonic acid