Respiratory SystemMore than just breathing

• Providing a large area for gas exchange between the air and circulating blood

•Moving air to and from the gas-exchange surfaces

• Protecting the respiratory surfaces from dehydration and temperature changes and

defends against invading pathogens

• Produces sounds for auditory communication

• Provides olfactory sensations - smellFunctionsOf the Respiratory System

The Respiratory System

Additional things it does

Delivers air to the lungsFiltersWarms

Humidifies

Delivers air free ofDebris

Pathogens And protects the lungs from environmental extremes

General OrganizationOf the Respiratory System

Conducting portionBegins at the entrance to the nasal cavity though the pharynx, larynx, trachea, bronchi and bronchioles

Respiratory portionThe smallest and most delicate

bronchioles and alveoli

The Nose

External Nares (NA rez)Nostrils

Nasal CavityNasal vestibule contains course hairs that stop large airborne

particlesDust, bugs, sand, saw dust, spay paint

Nasal septumDivides the nasal cavity into left and right sides

Internal NaresThe area where the nasal cavity opens into

the nasopharynx

Hard palate, soft palate Lies below the nasopharynx, top of the mouth

Internal View of the Nose

As air enters the nose it swirls around

like water flowing over rapids

andAirborne particles are caught by the

mucus

These activities warms, cleans and humidifies the air

The frontal, sphenoid, ethmoid and maxillary sinuses produce mucus that catches the particles.

When exposed to allergies, dust or vapors mucus production picks up and the nose begins to “run”

The Pharynx (FAIR-inks)The Throat Shared by the digestive and respiratory systems

Between the internal nares and the entrance to the larynx and esophagus

3 SubdivisionsNasopharynxOropharynx

Laryngopharynx

The Larynx

GlottisOpening to the larynx, voice box

EpiglottisTissue that projects from the glottis – folds back over the glottis preventing food and liquids from entering the respiratory tract

Thyroid cartilageWraps around anterior and

laterlally to protect the larynx – adam’s apple

Cricoid carlitagePosterior protection and

contains the cartilages that contain the vocal cords

Protects the glottis and vocal cords

When food or liquid touches the vocal cordsIt triggers the coughing reflex

Tracheawindpipe

Is betweenC 6 vertebra to T 5 vertebra

About 4.5 inches longAbout 1 inch in diameter

Tracheal cartilages Keep it from collapsing or

over expanding

Anterior to the esophagus

Splits to form the primary bronchi

Bronchi

d

The right and left sides – bronchi – are different.

Why?When one chokes the particles usually find their way to the right

primary bronchi because of its size and angel

What is the bronchial

tree?

Secondary bronchi

Tertiary bronchi

Bronchioles

Bronchoconstriction

Bronchodilation

Terminal bronchioles divide to

Form respiratory bronchioles

Then to the gas exchange surfaces

AlveoliGas exchange area

Bronchioles open into passageways called

Alveolar ducts

Ducts end at

Alveolar sacs

Each lung has about 150 million alveoli.

That would be about140 square meters of

surface area

Alveoli are very thin squamous epithelium

Macrophages are policeman on guard

roaming around phagocytizing dust and other debris on alveoli

surfaces

Septal cells secrete surfactant that reduces

surface tension caused by water and keeps the

alveoli supple and won’t let them stick together so

they inflate

Lungs are located in the plural cavity

superior

middle

inferior

superior

inferior

Superior endJust under the first rib

Base rests on the diaphragm

Lungs contain elastic fibers to help them tolerate the changes in volume.

Respiratory terms

Pulmonary ventilationBreathing – movement of air into and out of the lungs

Gas exchangeGas diffusion at two sites: Across the respiratory membrane between

alveolar air spaces and alveolar capillaries and across capillary cell membranes between blood and other tissues.

Gas transportThe transport of oxygen and carbon dioxide to and from the alveolar

capillaries and the capillary beds in other tissues.

Terms used to describe breathing

Compliance of the lungsIndicates the lungs resilience and ability to expand.

The lower the compliance the more resistance, the greater the force to inflate the empty lungs.

The greater the compliance, the easier it is to fill the empty lungs.

Quiet breathingMuscular contraction causes inhalation, exhalation is passive

Forced BreathingInhalation and exhalation are both active such as during exercise

Respiratory cycleOne inhalation and exhalation

Terms continued

Tidal volumeThe amount of air moved in and out of the lungs during a single

respiratory cycle

Expiratory reserve volumeDuring quiet respiration inhalation VT is about 500 ml

but exhalation can be about 1000 ml. The extra exhalation is called Expiratory reserve volume.

Inspiratory reserve volumeThe amount of air that can be taken in over and above the resting tidal

volume. Males have larger lungs than females3300ml in males - 1900 ml in females

Residual volumeThe amount of air that remains in the lungs even after maximal

exhalation1200 m. in males 1100ml in females

Terms continued

PheumothoraxBreaks the fluid bond between the pleurea – visceral plaura and parietal

pleura - and allows the elastic fibers to contract Collapsed lung

HemothoraxThe lung volume is reduced by the accumulation of blood in the pleural

cavity

Minimal volumeWhen the chest acvity has been penetrated as in a pheumothorax, when

the lungs collapes, and the amount of air in the respiratory system is reduced to the minimal volume

HypoxiaOxygen concentrations lower and tissues will become oxygen starved

AnoxiaOxygen is cut completely off from tissues cells die quickly

usually the result of strokes or heart attacks

Discussion questions

1. In the trachea the cartilages are C-shaped. Why would C-shaped cartilages functionally better that completely circular cartilages?

2. What would happen to the alveoli if surfactant were not produced?

3. John break a rib and it punctures the chest wall on this left side. What might be the outcome?

4. Fluid accumulates in the alveoli of the lungs. How is the vital capacity affected?

5. Systic Fibrosis is a genetic disease of the lungs. The lungs fill with a sticky substance. How does this affect breathing?

6. Hemoglobin within RBCs carries most of the oxygen in the bloodstream, and it releases it in response to change in the oxygen

partial pressure in the surrounding plasma. If the PO2 increases, hemoglobin binds oxygen; if the PO2 decreases, hemoglobin

releases oxygen. At a given PO2 hemoglobin will release additional oxygen if the pH decreases or the temperature increases.

How does this affect oxygen exchange during exercise? (active tissues release an acid)

Explain how carbon dioxide is carried in the blood. Read Carbon Dioxide Transport beginning around page 500

More vocabAtelectaisis

Bronchitis dyspenea

Hypercapnia

Hypocapnia

Pleurisy

Pheumonia

Pulmonary enbolismtracheostomy

Additional vocabulary