Download 17.3

The Respiratory System
Chapter 17 Lesson 3
Function of the Respiratory System
 Respiration (the exchange of gases between your body and your
environment).
 2 parts:
 External respiration: exchange of oxygen and carbon dioxide between the blood and
air in the lungs.
 Internal respiration: exchange of gases between the blood and cells of the body.
Structure of the Respiratory System
 Lungs
 Nose
 Mouth
 These are supported by the diaphragm (a muscle that separates the chest
and abdominal cavities).
 Without the diaphragm, respiration would be impossible.
Lungs
 Principal organ of your respiratory system.
 Take in oxygen from the air you inhale and return carbon dioxide (c02) to
the air when you exhale.
 Lungs get their power from the diaphragm.
The Breathing Process
 When you inhale, the rib muscles and diaphragm contract.
 Diaphragm moves downward and ribs pulled up and out.
 This movement enlarges the chest cavity, creating lower pressure in the lungs.
 Air rushes into the lungs to equalize the pressure between the lungs and
outside environment.
 The reverse happens when you exhale (diaphragm relaxes, moving upward, and
the ribs move inward, increasing pressure within the lungs.
 Video
Structure of the
Lungs
 Each lung is divided into sections
called lobes.
 3 lobes in the right lung & 2 in the left.
 The airways that lead into the lungs
divide to form a network called
bronchioles.
 At the end of each bronchiole is a
cluster of thin-walled air sacs called
alveoli.
 These alveoli are covered with a lots of
capillaries.
 It is these alveoli where the exchange
of air and carbon dioxide take place.
Other Respiratory Structures
 There are two points of entry for air to get to your lungs:
 Nose & Mouth
 Breathing through the nose has an advantage in that it is filtered and
cleaned by mucous membranes and tiny hairs called cilia.
 From your nose, air moves through the pharynx (throat) and into the
trachea (windpipe).
 The trachea is also lined with mucous membranes and cilia.
 These are the 2nd line of defense to trap foreign particles and keep them from entering
your lungs.
 Air completes its journey to the lungs through the bronchi (the airways that
connect the trachea to the lungs).
Larynx & Epiglottis
 On its journey to the lungs, air passes over two
structures that are not directly related to
inspiration (when oxygen is taken in) – but are
very important.
 Larynx (voice box)
 Contains vocal cords. As air passes over
these cords, the cords vibrate and
produce sound. Without them, speech is
not possible.
 Epiglottis (flap of cartilage in front of the
entrance to the larynx).
 At rest, the epiglottis is open to allow air to
pass into the lungs.
 When you swallow, it closes to prevent
food and liquid from being inhaled.
 “Went down the wrong pipe”
 Epiglottis failed to close properly,
allowing food or drink to enter your
trachea.
Care of the Respiratory System
 Respiratory System (RS) is highly susceptible to infection from both bacteria
and viruses.
 Avoid putting your hands up to your nose or mouth – as your hands are a
carrier of disease organisms. It is vital to develop an awareness of this habit
and do it less. Wash your hands!
 Avoid pollutants such as tobacco smoke.
 Exercise regularly! This helps to keep your lungs working efficiently.
Respiratory System Problems
 Bronchitis
 Asthma
 Pneumonia
 Tuberculosis
 Emphysema
 Sinusitis
Bronchitis
 Inflammation of the bronchi.
 Symptoms: wheezing, shortness of breath, and
coughing.
 Can be acute or chronic. Both types are
common in smokers and areas of high pollution.
 Acute bronchitis comes on suddenly and usually
clears up quickly. It is usually a complication of a
viral infection such as cold or flu.
 Chronic bronchitis is longer-lasting, and recurring.
 Most important in the treatment of chronic
bronchitis is avoiding respiratory irritants such
as cigarette smoke, dust, fumes, and other
air pollutants.
Asthma
 Is an inflammatory condition in which the
small airways in the lungs called bronchioles
become narrowed, causing difficulty
breathing.
 The mucous lining swells and secretions
build up, making breathing more difficult.
 Can be triggered by exertion, emotion,
infection, allergies, weather.
 1 in 20 people (1 in 10 children) are
asthmatic.
 Treatment: bronchodilators – medicine that
relaxes and widens airways.
 Most people administer the medication
themselves.
Pneumonia
 Pneumonia is inflammation of the lungs.
 Not a single disease but the name for several types of lung
inflammation caused by bacteria or viruses.
 2 main types:
 Lobar pneumonia
 One lobe of the lung is affected at first.
 Bronchial pneumonia
 Inflammation starts in the bronchi and then spreads to
lungs
 Symptoms: fever, chills, shortness of breath, sever cough.
 Chest pain that is worse when breathing may occur because
of pleurisy (inflammation of the membrane lining of the lungs
and chest cavity).
Tuberculosis
 Infectious bacterial disease of the lungs.
 Symptoms: fever, sweating, weakness,
poor appetite, shortness of breath, sever
coughing.
 Pretty care in developed countries (such
as U.S.) because on modern antibiotic
medicines/immunizations.
Emphysema
 Disease in which the alveoli in the
lungs burst and blend to form
fewer, larger sacs with less
surface area. As a result, normal
exchange of carbon dioxide and
oxygen in alveoli is disrupted.
 Symptoms: difficulty breathing,
chronic cough.
 Cause: breathing in foreign
matter such as smoke, and other
air pollutant over a long period of
time. In almost all cases it is
caused by cigarette smoking.
 The condition cannot be
reversed.
Sinusitis
 Sinusitis is an inflammation of
the membrane lining the
facial sinuses, the air-filled
cavities in the bones that
surround the nose.
 Cause: infection that spreads
to the sinuses from the nose.
 Symptoms: fever, stuffy nose,
ache in affected area
 Treatment: antibiotics,
decongestant drops/spray, or
steam inhalation