Respiratory System:A Breath of Fresh Air

What is Cystic Fibrosis?• Hereditary disease affecting mucus glands of

lungs, liver, pancreas & intestines• This recessive disease causes mucus buildup

in respiratory airways• Leads to lung and sinus disease since

bacteria that normally inhabit the thick mucus grow out of control and cause pneumonia.

• Leads to multisystem failure- although patients usually die in the 20s and 30s due to lung failure

• Lung transplantation is often necessary as it gets worse

• In addition, people with CF often develop clubbing of their fingers and toes due to the effects of chronic illness and low oxygen in their tissues.

Clubbed fingers

Fluids• A fluid is a substance that has no defined

form and can flow in all directions. ALL LIQUIDS AND GASES ARE FLUIDS!

• If fluids are compressible, their volume DECREASES when a force is applied to it.

ex: gases, like air, are compressible•If a fluid is incompressible, the volume cannot be decreased by adding force to itex: liquids, like water, are incompressible

Air compositionAir is a fluid and it is a mixture of:

• 78% Nitrogen

• 21% Oxygen

• 1% trace gases, such as Argon, Neon, Carbon dioxide, Helium, Methane, Hydrogen and water vapor

Why do we need Oxygen?• If the brain goes without oxygen for four

minutes, it can be permanently damaged.

• Oxygen is used for cellular respiration, turning glucose into energy for the cells (oxidation reaction!!)

Glucose + O2 CO2 + H2O + ENERGY

•When you exhale, you release carbon dioxide and water vapor

Purpose of Respiratory System1) Provide the body with Oxygen

2) Provide a transfer site for Oxygen into the blood stream to be circulated throughout the body.

3) Eliminate Carbon dioxide from the body.

Respiratory AirwaysWhat do they do?

1. Take in air2. Warm up and

moisten air3. Remove foreign

particles from the air

Anatomy of the Respiratory System

The 6 main parts:

1. Nasal Cavity

2. Pharynx

3. Larynx

4. Trachea

5. Bronchial tubes (Bronchi & Bronchioles)

6. Lungs (Alveoli)

Nasal CavityFunction:

• Filters, warms, and moistens air as it enters

• It also contains FOUR SINUSES

Respiratory Defense…… against Foreign Particles:

1. Nostril hair

2. Mucus in the respiratory tract

3. Cilia in the trachea and bronchial tubes

PharynxFunction:

• Handles air between nasal cavity and trachea

• Also contains the Tonsils

Larynx• Made of cartilage• Also called the Adam’s Apple or voice box

because it holds the vocal chords• The Epiglottis is found at the top of the larynx

Trachea• Function:

• Has cilia which filters particles in the air.

Bronchial Tubes

• Made up of cartiliginous rings, like the trachea

• Function: Filter particles in the air.

LungsFunction:

1. Remove Oxygen (O2) from the air and put it into the bloodstream

2. Remove Carbon Dioxide (CO2) from the bloodstream and release it into the atmosphere.

Lungs

Function:• Alveoli are thin, permeable sacs which are the functional

units of the lungs- this is where gas exchange takes place.• They are made up of a SINLGE LAYER OF CELLS!• There are 300 million in each lung!

Alveolar Network looks like an upside down tree!

Gas ExchangeFor this to happen, we need 2 things:• Diffusion: movement from an area of higher

concentration of that substance to an area of lower concentration.

• Selectively permeable membrane: a membrane that only allows certain substances to pass through.

Gas Exchange

Lower Concentration ofO2

Lower concentration ofCO2

Selectively-permeable membrane

Clip: The Respiratory System

Breathing

Pressure and breathing• When air pressure is low, it becomes more difficult

to breathe• Pressure is the measurement of force exerted on

a surface (P in pascals)= Force (in Newtons) Area of surface (in meters2)

1 N/m2 = 1 Pa101.3 kPa = 760 mm of Hg = 1 atm

•Since air is made up of matter, it has mass and can exert force•The fewer air particles, the less force is exerted, the smaller the air pressure•This makes it hard to breathe

• Relationship between Pressure and applied Force : As the force increases, pressure increases

• Relationship between Pressure and Area: As area increases, pressure decreases

Bed of Nails!!

Back to Fluids…• Compressible fluids, like air, can decrease in

volume when pressure increases. This is because force increases.

• Fluids like to move from areas of high pressure to areas of low pressure.

• Think of what happens when you breathe: inhaling causes a decrease in pressure, allowing air to enter lungs

• Exhaling causes an increase in pressure, pushing air out

You are squeezing the particles of air closer together every time you

exhale

Mechanism for inspiration (inhaling) and Expiration (exhaling)Inspiration Expiration

Intercostal muscles contract, ribs move out and up

Intercostal muscles relax, ribs move in and down

Diaphragm contracts, moves down

Diaphragm relaxes, moves up

Volume of chest cavity (thorax) and lungs increases

Volume of chest cavity (thorax) and lungs decreases

Intrapulmonic pressure decreases causing air to enter lungs

Intrapulmonic pressure increases, causing air to exit lungs

TobaccoEffects:

• Deterioration of the respiratory system resulting in diseases such as bronchitis and emphysema.

• Cardiovascular diseases characterized by damage to the heart and blood vessels.

TobaccoChanges in blood composition:

• Level of carbon monoxide, a toxic gas, increases- it binds readily with red blood cells, thus a loss of binding sites for O2 so transportation of O2 to the cells is greatly reduced.

And…

Lung Cancer• Estimates suggest that

tobacco causes at least 40% of all types of cancer and at least 90% of all cases of lung cancer

• Bottom line: Tobacco reduces life expectancy

Smoking and pregnancyEssentially, what the woman

breathes, so does the baby.

• So it can cause:

• stillbirths,

• premature babies,

• spontaneous abortions

• low weight babies

• And neurological damage

Air pollutants• Carbon monoxide.• Insecticides• Gasoline fumes• Sulphur dioxide =

acid rain• Dust particles,

soot and sand, can clog the alveoli as well.

Improving Air Quality1. Reduce the emissions of

pollutants through legislation and the imposition of harsh fines.

• Ban smoking in public spaces and tougher regulations for industry

2. Expand the number of green spaces in cities and protect those already in place.