The Breathing System

Chapter 5

Why are the lungs important?

                                                                 

RespirationRespiration is the breakdown of food to give

energy.Food + Oxygen Energy + Carbon Dioxide + Water

Vapour

This reaction is called aerobic respiration because it involves oxygen.

• The breathing system involves taking in the Oxygen required and giving out Carbon Dioxide and water vapour.

Experiment To show that respiration produces energy.

1) Set up apparatus as shown in diagram.

2) Over a week, record the temperature in each flask.

Result

• The temp will have risen in the flask containing the live seeds but there will be no change in temp in the flask containing the boiled seeds

Experiment. To show that respiration produces CO2

1) Set up apparatus as shown in diagram.

2) In test tube A are woodlice.

3) In test tube B are no woodlice.

• Result

The limewater in A will turn

milky

The lime water in B will not turn

milky.

The woodlice released CO2

A B

Experiment:To show that CO2 is a product of aerobic respiration in plants

Experiment: To show that respiration produces water vapour.

1) Dry the surface of a mirror.

2) Breath on to the mirror to produce condensation.

3) Test this with blue Cobalt chloride paper.

Result

The blue cobalt chloride paper turns a pink colour.

Water vapour is released during respiration.

Experiment:To show that expired air has more CO2 than inhaled air.

1) Breath in through tube X. Note how long it takes the limewater to turn milky

2) Breath out through tube Y Note how long it takes the limewater to go milky.

Result

It takes longer for the limewater in

X to go milky. There is more CO2

in the air we breath out than in the

air we breath in.

The Breathing System

The functions of the breathing system are:

• To take in Oxygen

• To excrete Carbon dioxide gas and Water vapour.

• Inhalation is breathing in.

• Exhalation is breathing out.

Parts of the breathing system

Larynx

Trachea

Right Bronchus

Bronchiole

Alveoli

Diaphragm

Intercostal muscles

Rib cage

Rings of cartilage

Lungs

Healthy lung

Breathing system Larynx (voice box)-allows us to make sounds. Trachea-passes air to lungs. Rings of Cartilage-keep airways open Bronchus-air carried from trachea to lungs Bronchioles-tiny tubes taking air to alveoli Alveoli-tiny air sacs where gaseous exchange takes

place Diaphragm-a sheet of muscle that moves down to

draw air into the lungs and to expel air out of the lungs.

Taking a breathWhen taking a breath:

The diaphragm pulls downwards The rib cage expands

Bell jar model

The bell jar model demonstrates how the diaphragm works.

If you pull down the rubber sheet(diaphragm) what will happen to the balloons(lungs)?

Gaseous exchange Gaseous exchange

takes place in the alveoli.

The walls of the alveoli are only 1 cell thick and each alveolus is surrounded by tiny blood vessels called capillaries.

Oxygen moves from the alveolus into the blood.

Carbon Dioxide and water vapour move from the blood into the alveoli and then are breathed out

Gaseous exchange occurs in the alveolus.

The effects of smoking

Smoking is harmful to the breathing system.

• It can cause lung cancer, bronchitis and emphysema.

• It can also cause heart attacks and can lead to stunted growth of a baby.

• It causes bad breath

The cotton wool becomes discoloured as the cigarette smoke is drawn through it

Emphysema + Lung cancer

Why Do I Yawn?

 

When you are sleepy or drowsy the lungs do not take enough oxygen from the air. This causes a shortage of oxygen in our bodies. The brain senses this shortage of oxygen and sends a message that causes you to take a deep long breath---a YAWN.

Why Do I Sneeze?

     Sneezing is like a cough in the upper breathing passages. It is the body's way of removing an irritant from the sensitive mucous membranes of the nose. Many things can irritate the mucous membranes. Dust, pollen, pepper or even a cold blast of air are just some of the many things that may cause you to sneeze.

• .

What Causes Hiccups?

    Hiccups are the sudden movements of the diaphragm. It is involuntary --- you have no control over hiccups, as you well know. There are many causes of hiccups. The diaphragm may get irritated, you may have eaten to fast, or maybe some substance in the blood could even have brought on the hiccups