RESPIRITORY SYSTEM
Body in Action

How do we breath?
The Respiratory system

We will aim to learn to:
 Identify what the respiratory system is,
 Know what the respiratory system is made up of,
 The functions of the respiratory system,
 How it works during exercise.

So, what is the respiratory system?
The respiratory system is the system in your body which allows you to breath in air and stay alive.

What makes up the respiratory system?
There are many parts to the respiratory system these are:
 The Nasal cavity
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The Epiglotis
The Larynx
 The Trachea (wind pipe)
 The Bronchi (each one is a bronchus)
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The Bronchioles
The Alveoli
 The Thoracic cavity
 The Pleural membrane
 The Ribs
 The Intercostal muscles
 The Diaphragm

Each part of the RS has a function these are:
 The Nasal cavity: Hairs in the nose filter and mucus warms and moistens the air.
 Cilia : These are coarse hairs that trap bacteria and large dust particles and send them down the throat to be swallowed.
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The Epiglottis: This small piece of cartilage prevents air travelling down the food pipe.
The Larynx: Makes sound for speaking when air passes through it.
The Trachea (wind pipe):
This is a large flexible tube surrounded by rings of cartilage to prevent it from collapsing.

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The Lungs : The 2 major organs of the respiratory system, they are soft, moist, spongy air sacs.
The Thoracic cavity: The space which the 2 lungs occupy.
The Pleural membrane:
A Slippery skin lining the cavity.A “protective device”by stopping friction between the lungs and ribs.
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The Bronchi (each one is a bronchus): These branch air into each lung.
The Bronchioles: The
Bronchi branch into these and take air further into the lungs,
The Alveoli: These are tiny air sacs. There walls are so thin so gaseous exchange can occur. When the lungs contract the air sacs fill and empty.

 The Ribs: Protect the lungs.
 The Intercostal muscles:
Muscles between the ribs which help you breathe.
 The Diaphragm: Sheet of muscle below the lungs sealing of the chest from the abdominal cavity

Breathing in:
Nasal Cavity / Mouth
↓
Trachea
↓
Bronchi
↓
Bronchioles
↓
Alveoli
↓
Blood
Breathing out:
Blood
↓
Alveoli
↓
Bronchioles
↓
Bronchi
↓
Trachea
↓
Nasal cavity / Mouth

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The Alveoli is where gaseous exchange occurs.
Found at the end of the bronchioles , each smaller than a grain of salt.
Have thin, moist walls to help gases pass through.
They are covered with tiny blood vessels called capillaries. Gases pass through the capillary walls.

Task:
Copy out the labels and label your diagram.
The picture opposite shows what happens .
1.
Blood carries waste CO2 from body to Alveoli.
2.
CO2 passes through capillary walls into
Alveoli.

3.
4.
5.
6.
CO2 travels out of lungs and up windpipe, you breathe it out.
You breathe in O2 and it travels to the alveoli.
O2 passes through the alveoli walls and into the capillaries and blood stream.
The blood carries the O2 away to the body cells.

Into the lungs :
 O2 = 21%
 CO2 = tiny amount


Nitrogen (N2)=
79%
Water Vapour
(H20) = a little
Out of the lungs:


O2 = 17% (reduced as the body has used some)
CO2 = 3% (increased as body has produced some)

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Nitrogen (N2) = 79%
(body doesn’t use, but a component of air)
Water vapour (H20) = a lot (increased as a by product of aerobic respiration)

It’s the same principle with a syringe and the bellows.
Breathing in: (syringe) we must first make the volume of the thorax
(chest) larger, in order to breathe in.
Breathing out: (bellows)
We must make the volume smaller again in order to breathe out.
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So how do we breathe in and out?
What happens to our chest, what can you feel happens?
 How does air travel in and out during breathing?

To Inhale:
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Diaphragm muscle flattens
Intercostal muscles contract lifting rib cage up.
Thorax volume increases.
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Decrease in atmospheric pressure in the lungs = air sucked in.
An Increase in Volume = a decrease in pressure – air enters.

To Exhale:
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Diaphragm muscle relaxes.
Intercostal muscles relax,
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Ribs relax and fall.
Thorax volume decreases.
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Increase in atmospheric pressure in the lungs = forcing air out.
A decrease in volume = increase in pressure – air is forced out.

Tidal Volume: The amount of air you breathe in or out each breath (breathing deeply increases this).
 Minimum = 3ml/kg
Minute Volume: Amount of air you breathe in per minute. Calculated by:
MV = Tidal volume X
Respiratory rate
 Normal = 6-7ml/kg
Respiratory Rate: How many breaths you take a minute.
Vital Capacity: Maximum amount of air you can breathe out in one breathe, after breathing as deeply as possible = 4.5 – 5 litres .

Total lung Capacity: Volume in lungs after max inspiration = 4 - 6litres .
Calculated by:
TLC = VC + RV
Task:
I would like you to calculate your Minute
Volume.
Residual Volume: Amount of air left in your lungs after you breath out as hard as you can = 1.0 – 2.4litres
, you can never empty your lungs completely.
MV = Tidal volume X
Respiratory rate

Your lungs and heart work as a team to get more O2 round the body and clear
CO2 away. When you exercise your lungs and heart have to work harder.
 So what happens to the lungs to cope exercise?

During exercise the following occurs:
1.
Cell respiration in your muscles increases = increased levels of CO2 in blood.
2.
3.
Your brain detects this, sends a signal to lungs to breathe faster and deeper.
So gas exchange in your lungs speeds up. More
CO2 passes out of blood and more O2 passes into it.

4.
The brain also sends a signal to your heart to beat faster, so:
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More blood gets pumped to the lungs for gas exchange,
More blood gets pumped to the muscles, carrying
O2 and removing CO2.

Look at how breathing changes during exercise:
For an 18 year old … At rest
Tidal volume 0.5
litres
During
Exercise
2.5
litres
Respiratory rate
Minute Volume
12 breaths a minute
6 litres a minute
30 breaths a minute
75 litres a minute

As shown in the previous table, several things happen to tidal volume, respiratory rate and minute volume.
Task:
(1)
In pairs I want you to see whether that is true!
Count your breaths for one minute while at rest,
(2)
(3)

Count your breaths when jogging slowly on the spot,
Count your breaths while jogging hard on the spot, raising your knees.
Get your partner to time you and then swap over to have a rest between each part.
 What do you notice, is it true?

 http://www.bbc.co.uk/schools/gcsebitesize/p e/appliedanatomy/