The Respiratory System

Class Starter Questions:

1) What are 3 functions of the respiratory system?

2) Explain the difference between breathing and cellular respiration.

3) What organs make up the respiratory system? Write them in order through which air passes during inhalation.

1) What are 3 functions of the respiratory system?

To provide oxygen to body cells so that they may extract the energy they need from nutrients. (cellular respiration)

To remove carbon dioxide (waste product) from the body.

To filter, warm and humidify the air we breathe.

2) Explain the difference between breathing and respiration.Breathing is:

The process which moves air in and out of the lungs

Cellular Respiration is:A chemical reaction that occurs inside the mitochondria of all cells. It is a combustion reaction, therefore it always releases energy.

Chemical equation for cellular respiration:

C6H12O6 + 6 O2 6 CO2+ 6 H2O + energy

3) Pathway of air through the respiratory system.

Nose & mouthNasal pasage

PharynxLarynxTracheaBronchi

BronchiolesAlveoli

Capillaries (where O2 enters the blood)

Lungs

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Mouth & Nose This is where the oxygen first

enters your body and also where carbon dioxide leaves.

When the air comes into your nose it getsfiltered by tiny hairs (not cilia)

Your mouth does not contain these hairs therefore breathing by your mouth does not filter the air as well as breathing by your nose

Nasal cavityWarms & humidifies air Glands that produce sticky mucus line

the nasal cavity traps dust, pollen, and other materials

that were not trapped by nasal hairs

PharynxTube-like passageway used by food,

liquid, and air. At the lower end of the pharynx is a flap

of tissue called the epiglottis. covers the trachea during swallowing so

that food does not enter the lungs

Larynx“Voice box”The airway to which two pairs of

horizontal folds of tissue, called vocal cords, are attached

When we exhale, the vocal cords vibrate which produces sound

TracheaThis is an air-conducting tube that

connects the larynx with the bronchiLined with mucus membranes and ciliaContains strong cartilage rings to hold

the airway open at all times

BronchiTwo short tubes that branch off the lower

end of the trachea Carry air into the lungs. Singular - bronchus

LungsThe lungs are spongy organs which

contain the bronchioles and alveoli.Where gas exchange occursThere are 2 lungs (right and left)

Smoker’s Lung vs. Healthy Lung

BronchiolesTiny branches of air tubes in the lungs Connect bronchi to alveoli

AlveoliTiny, thin-walled, grapelike clusters at

the end of each bronchiole Surrounded by capillariesWhere exchange of carbon dioxide and

oxygen (via diffusion) takes placeSingular - alveolus

PleuraA double membrane that lines the lungs

and adheres to the walls of the rib cage

Diaphragm• Dome shaped muscle between the chest and

the abdomen that the body uses for breathing

Gas Exchange- What is it?Two gases, O2 and CO2 switch placesO2 moves from the alveoli to the capillariesCO2 moves in the opposite direction, from the

capillaries to the alveoliThis occurs by diffusion:

The movement of molecules from a region of high concentration to a region of low concentration

Diffusion of Carbon DioxideBlood arriving at

the alveolus is deoxygenated:Low in O2High in CO2

The concentration of CO2 inside the alveolus is lower than in the capillary

Thus, CO2 diffuses into the alveolus

Diffusion of OxygenBlood arriving at

the alveolus has a low concentration of O2

But air entering the alveolus has a high concentration of O2

Thus, O2 diffuses from the alveolus (high conc.) into the capillary (low conc.) Oxygenated blood

leaving the alveolus

How does breathing work?Breathing is an

involuntary action meaning that it occurs without conscious thought

However, breathing is in fact controlled by a structure in the brain called the medulla

Breathing RateBreathing rate = # of breaths (including

inhalation AND exhalation) in 1 minYour brain controls your breathing rate by

monitoring the level of CO2 in your bodyWhen CO2 levels are high, breathing rate

increasesWhen CO2 levels are low breathing rate

decreases

Why does your breathing rate increase during and after exercise?Physical activity requires increased

energy production Thus, your muscles must consume more

O2 to release more energy As a result of respiration, more CO2 is

producedThe increased levels of CO2 in the blood

flowing to your brain is a signal to the medulla to increase breathing rate

WHY?To remove CO2 and replenish O2 at a faster

rate