5th Year BiologyMoyle Park College

12/11/13

Introduction to the Human Breathing System

By the end of this we should be able to:• Draw a diagram demonstrating the

Macrostructure of the Respiratory system • Identify all the key structures of the

Breathing system on an unlabelled diagram• Explain the Function of each part of the

Breathing System• Describe the unique structure of the

Alveolus which make them adapted to gas exchange

Our Amazing Lungs

Team work

• Work together in groups of two and draw a diagram of the Human Breathing system labelling as many Key structures as you can!

The Structures we need to know

Key Structures:• Trachea: Passes air into the lungs, consists

of muscle and elastic fibres• Epiglottis: Closes off the Trachea, food and

other objects entering the airways• Larynx: muscle sheet which vibrates

causing sound• Bronchiole: Takes from air from Bronchus

to alveoli• Alveolus: Gas exchange occurs here

Key Structures

• Diaphragm: sheet of muscle down and up for inhaling and exhaling

• Bronchus: Trachea splits into the Bronchus, one enters each Lung

• Rings of Cartilage: Keep the airways open and prevents the Trachea from closing in on itself.

• Intercostal muscle: Move the rib cage up and down

Your lungs are enclosed (along with the heart) between the ribs and the diaphragm [the thorax]

The ribs form a protective cage of twelve pairs of bones.

The Alveolus

• O2 Diffuses into the Alveolus (Alveoli) and CO2 Diffuses out of the Alveolus

• What structures do You think the Alveolus would need to carry out this complex gas exchange process???

Breathing System- Class 25th Year Biology

19/11/13

What we should be able to do after today’s class………• Describe the unique structure of the Alveoli

which make them adapted to gas exchange• Discuss the role of the diaphragm and

intercostal muscles in inhalation• Discuss the role of the diaphragm and

intercostal muscles in exhalation• Describe a breathing disorder associated

with the lungs/breathing system

Alveoli are adapted to carry out gas exchange

1. Large surface areas of Alveoli (approx. the size of half a tennis court!)

2. Thin walls of alveoli (usually only one cell thick)

3. Alveoli are covered with a network of Capillaries

4. Alveoli are numerous (over 700 million! alveoli in the lungs).

Air enters the nose, travels down the windpipe, the bronchusand the bronchioles, to the alveoli.

Each alveolus is covered in a net of thin-walled bloodcapillaries.

The lining of an alveolus is only one cell thick

Oxygen diffuses through the alveolus and capillary linings, andattaches to red blood cells.

Diffusion is the movement of molecules from a region of high concentration to a region of lower concentration

At the same time, carbon dioxide diffuses from the plasma intothe alveolus.

The structure of the thorax6.

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3. 7.

Lets Recap

• What did we learn about the Breathing system in our last class??

• http://www.youtube.com/watch?v=cUzDbX3NTkM&oref=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DcUzDbX3NTkM&has_verified=1

Human Breathing SystemA Named Breathing Disorder

26/11/13

What we should be able to do after today’s class……• Describe in detail a named breathing

disorder explaining its biological cause• Outline in a scientific manner the effect of

exercise on breathing.• Discuss the role of the brain in controlling

breathing as an involuntary response.

Breathing disorders/diseases

• What breathing disorder/ disease did you research as your homework???

• What is the biological cause?• What are the symptoms?• What treatments are currently available?• What is the prognosis of your named

disorder/disease?

Role of Diaphragm & Intercostal muscles Inhalation

• Diaphragm contracts & moves down• Intercostal muscles contract and rib cage

moves up• The volume of the Thoracic cavity is

increased• The air pressure decreases and air is drawn

in to equalise pressure.

Role of Diaphragm & Intercostal musclesExhalation

• Diaphragm relaxes and moves up• Intercostal muscles relax and rib cage

moves down• The volume of the Thoracic cavity is

decreased• The air pressure increases and air is

expelled to equalise pressure

Inhalation V Exhalation

Breathing Disorders

• Can you name any breathing disorders??• What causes the disorder?• What are the symptoms?

What treatment is available currently?

Homework Assignment• In preparation for next week’s class you must complete

the following:• Do some independent research where you research any

breathing disorder/ disease associated with the lungs• Name the breathing disorder/disease• Give a scientific explanation of its cause• Description of the disease i.e. symptoms and effects, those

most at risk etc.• Available treatments and mortality rates• Must be at least two A4 pages long, and should include

images• List two sources where you found your information• Hand up in next week’s class on A4 paper• Make a Good effort!!

Asthma- A Breathing Disorder

• Asthma is the narrowing of bronchioles usually due to irritants or allergic response to allergens

• Biological Cause: Can be caused genetically, by infection, by smoking or by allergic response.

• Prevention: Use preventative inhalers containing bronchodilators or avoid allergens

Asthma

• Treatment: again is through the use of bronchodilators , exercise such as swimming has be found to have a positive effect in reducing the chance of developing asthma

Effect of Smoking on the Lungs

Effects of Smoking

• 40% of men who are heavy smokers will die before they reach retirement age, compared to 18% of non-smokers

• Women who smoke face increased risk of cervical cancer.

• Ten years after you quit, your body has repaired most of the damage smoking has caused.

Effect of Smoking

• http://www.youtube.com/watch?v=A75YtjvdYNw

• More deaths each year in the US are caused by tobacco use than by human immunodeficiency virus (HIV), illegal drug use, alcohol use, motor vehicle injuries, suicides and murders combined.

Effect of Exercise on Breathing

• How do you think exercise affects our breathing???

• Work together to explain in a “Scientific” way what is happens our breathing when we exercise

Control of the Human Breathing System by CO2 levels

• An increase in CO2 in the blood leads to increased levels of carbonic acid and this leads to a decrease in blood pH

• This is detected by the brain (medulla oblongata) causing the breathing rate to increase i.e. during exercise

• CO2 levels then decrease as do carbonic acid levels causing pH & breathing rate to return to normal

Medulla Oblongata

• Controls involuntary responses such as breathing, heart beat regulation and digestion.

Our Brain controls our Breathing

Our Brain controls our Breathing