respiratory system - Livingstone High School

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RESPIRATORY SYSTEM
The respiratory system generally includes tubes,
such as the bronchi, which are used to carry air
to the lungs where gas exchange occurs. The
diaphragm, like other muscles can contract and
relax. When someone inhales, the diaphragm
contracts and flattens and the chest cavity
expands. This contraction creates a vacuum that
sucks air into the lungs. When exhaling, the
diaphragm relaxes and returns to its previous
position (dome-like shape) and the air is
expelled from the lungs.
PARTS OF THE RESPIRATORY
SYSTEM

Nasal Cavity
 Epiglottis
 Pharynx
 Larynx
 Trachea
 Lungs
 Diaphragm
NASAL CAVITY

The nostrils or nares are usually located in the
openings of the nose in some animals. They open
to the outside and let air enter the body.
EPIGLOTTIS

The epiglottis is a cartilaginous
structure valve that covers the entry of
the larynx and moves up and down,
preventing food from entering it and
the trachea. It also marks the limit
between the oropharynx and the
laringopharynx. When breathing, air
passes through the pharynx and goes
towards the larynx while the epiglottis
remains opened.

The epiglottis closes when food gets
swallowed and goes down the pharynx.
This prevents food from obstructing
the larynx.
EPIGLOTTIS

The epiglottis guards the entrance of the glottis, the
opening between the vocal folds. It is normally pointed
upward during breathing with its underside functioning as
part of the pharynx, but during swallowing, elevation of
the hyoid bone draws the larynx upward; as a result, the
epiglottis folds down to a more horizontal position, with its
upper side functioning as part of the pharynx. In this
manner it prevents food from going into the trachea and
instead directs it to the esophagus, which is further down
the throat.
PHARYNX

The human pharynx is the part of the throat situated
immediately behind the mouth and the nasal cavity, and
above the oesophagus, the larynx, and the trachea. The
human pharynx is conventionally divided into three
sections: the nasopharynx , the oropharynx, and the
laryngopharynx. The pharynx is part of both the digestive
and the respiratory systems, and it plays an important role
in vocalisation.
LARYNX

The larynx, commonly called
the voice box, is an organ in the
neck of mammals involved in
protecting the trachea against
food aspiration, breathing and
sound
production.
It
manipulates pitch and volume.
The larynx houses the vocal
folds which are an essential
component of phonation. The
vocal folds are located just
below, where the tract of the
pharynx splits into the trachea
and the oesophagus.
TRACHEA

The trachea (or windpipe) is the bony tube that connects
the nose and mouth to the lungs. It is an important part of
the vertebrate respiratory system: when an individual
breathes, air that is caught flows into the lungs through the
windpipe.
LUNGS

The lungs are the essential breathing organs in many
animals, including most tetrapods, a group of fish, and
snails. In mammals and more complex life forms, the two
lungs are located in the chest on either side of the heart.
Their principal function is to transport oxygen from the
air into the bloodstream and release carbon dioxide from
the bloodstream into the air. This exchange of gases is
accomplished by the mosaic of specialised cells that form
millions of tiny, exceptionally thin-walled air sacs called
alveoli.
LUNGS
To explain the anatomy of the lungs, it is
necessary to discuss the passage of air
through the mouth to the alveoli. Once
air progresses through the mouth or the
nose, it travels through the oropharynx,
the nasopharynx, the larynx, the trachea,
and a progressively subdividing system of
bronchi and bronchioles, until it finally
reaches the alveoli where the gas
exchange of carbon dioxide and oxygen
takes place.
DIAPHRAGM


It is a dome-shaped muscle that
separates the chest cavity and the
abdominal cavity.
It is characteristic of all
mammals, and in birds it appears
in a rudimentary way.
INHALATION

Inhalation is initiated by the diaphragm and supported
by the external intercostal muscles. Normal
respirations are 10 to 18 breaths per minute, with
each lasting around 2 seconds. During vigorous
inhalation (at rates exceeding 35 breaths per minute),
or when approaching respiratory failure, accessory
muscles of respiration are recruited for support. These
consist of the sternocleidomastoid and platysma
muscles, and the scalene muscles of the neck.
Pectoral muscles and latissimus dorsi are also
accessory muscles.
INHALATION


Under normal conditions, the diaphragm is the primary
driver of inhalation. When the diaphragm contracts, the
ribcage expands and the contents of the abdomen are
moved downward. This results in a larger thoracic volume
and negative pressure (with respect to atmospheric
pressure) inside the thorax. As the pressure in the chest
falls, air goes into the conducting zone. Here, the air is
filtered, warmed, and humidified as it flows to the lungs.
During forced inhalation, as when taking a deep breath,
the external intercostal muscles and accessory muscles aid
in further expanding the thoracic cavity.
EXHALATION



Exhalation is generally a passive process; however,
active or forced exhalation is achieved by the abdominal
and the internal intercostal muscles. During this process
air is forced or exhaled out.
The lungs have a natural elasticity: as they recoil from
the stretch of inhalation, air flows back out until the
pressures in the chest and the atmosphere reach
equilibrium.
During forced exhalation, as when blowing out a candle,
expiratory muscles including the abdominal muscles and
internal intercostal muscles generate abdominal and
thoracic pressure, which forces air out of the lungs.
HEALTHY HABITS FOR CARING
FOR OUR RESPIRATORY SYSTEM










Exercise regularly, this helps to improve the circulation of the
blood.
Eat a well balanced diet.
Eat vegetables, especially green vegetables.
Avoid eating too much saturated fats. Use beneficial fats and oils.
Maintain a healthy weight.
Live in a clean environment.
Avoid smoking cigarettes and second hand smoke. Smoking
increases the risk of stroke and coronary heart disease.
Have a positive outlook in life.
Try to reduce stress and tension.
Avoid high blood pressure because this can cause heart failure
and stroke.
DISEASES OF THE
RESPIRATORY SYSTEM

Respiratory diseases can be classified in many different ways:
by the organ involved, by the pattern of symptoms or by the
cause of the disease. The main thing is to always be careful
around food because some foods can cause allergic reactions
and incite breathing difficulties. Some common examples
include seafood (like prawns), some fatty fish, radish, arrow
root, fish fingers, lemon, dhal, peanuts (dry fruits in general),
water content spinach, curd, bananas, grapes, pomegranates,
berries, custard apple, ice creams, etc. In the summer, bad
weather conditions mean sandy and dusty weather or for some
people, bad weather may be affect them in winter also.
INFLAMATORY LUNG DISEASE

Inflammatory lung disease is also called Chronic
Obstructive Pulmonary Disease (COPD) and includes
a wide range of inflammatory lung ailments. These
ailments include asthma, emphysema and chronic
bronchitis. In many cases, the lungs are chronically
inflamed, making it difficult to breathe and placing
strain on the heart. Individuals with inflammatory
lung disease may find it difficult to engage in exercise
or activities that require heavy breathing. COPD is an
illness that is gaining in frequency as pollution in our
air increases.
ASTHMA

Asthma is a common chronic inflammatory disease of the airways
characterized by variable and recurring symptoms, reversible
airflow obstruction, and bronchospasm. Symptoms include
wheezing, coughing, chest tightness, and shortness of breath.
 Treatment of acute symptoms is usually with an inhaled short-acting
beta-2 agonist . Symptoms can be prevented by avoiding triggers,
such as allergens and irritants, and by inhaling corticosteroids.
Leukotriene antagonists are less effective than corticosteroids and
thus less preferred.
 The prevalence of asthma has increased significantly since the
1970s. As of 2009, 300 million people were affected worldwide. In
2009 asthma caused 250,000 deaths globally. Despite this, with
proper control of asthma with step down therapy, prognosis is
generally good.
RESPIRATORY TRACT
INFECTION







Respiratory tract infections affect the nose, the throat, and the
airways, and may be caused by any of several different
viruses.
Common respiratory tract infections include the common cold
and influenza (flu).
Typical symptoms include nasal congestion, a runny nose,
scratchy throat, cough, and irritability.
The diagnosis is based on symptoms.
Good hygiene is the best way to prevent these infections, and
routine vaccination can prevent influenza.
Treatment aims to relieve symptoms (palliative effect).
There are two types: Lower and Upper respiratory tract
infections.
RESPIRATORY TUMOURS



Malignant tumours
Malignant tumours, or cancers of the respiratory system,
particularly lung cancers, are a major health problem responsible
for 15% of all cancer diagnoses and 29% of all cancer deaths.
The majority of respiratory system cancers are attributable to
smoking tobacco.
In addition, since many cancers spread via the bloodstream and
the entire cardiac output passes through the lungs, it is common
for cancer metastases to occur within the lung. Breast cancer may
invade directly through local spread, and through lymph node
metastases. After metastasis to the liver, colon cancer frequently
metastasizes to the lung. Prostate cancer, germ cell cancer and
renal cell carcinoma may also metastasize to the lung.

Treatment of respiratory system cancer depends on the type of
cancer. Surgery , chemotherapy and radiotherapy are all used.
The chance of surviving lung cancer depends on the cancer
stage at the time the cancer is diagnosed and is only about 1417% overall. In the case of metastases to the lung, treatment
can occasionally be curative but only in certain, rare
circumstances.

Benign tumours
Benign tumours are relatively rare causes of respiratory disease. Examples
of benign tumours are:
Pulmonary hamartoma.
Congenital malformations such as pulmonary sequestration and congenital
cystic adenomatoid malformation.



PLEURAL CAVITY DISEASES

Pleural cavity diseases include emphysema and mesothelioma which
are mentioned above.
 A collection of fluid in the pleural cavity is known as a pleural
effusion. This may be due to fluid shifting from the bloodstream into
the pleural cavity due to conditions such as congestive heart failure
and cirrhosis. It may also be due to inflammation of the pleura itself
as can occur with infection, pulmonary embolus, tuberculosis,
mesothelioma and other conditions.
 A pneumothorax is a hole in the pleura covering the lung, allowing
air in the lung to escape into the pleural cavity. The affected lung
“collapses” like a deflated balloon. A tension pneumothorax is a
particularly severe form of this condition where the air in the pleural
cavity cannot escape, so the pneumothorax keeps getting bigger
until it compresses the heart and blood vessels, leading to a life
threatening situation.
PULMONAR VASCULAR
DISEASE

Pulmonary vascular diseases are conditions that affect
the pulmonary circulation.
 Pulmonary embolism, a blood clot that forms in a
vein, breaks free, travels through the heart and lodges
in the lungs. Large pulmonary emboli are fatal,
causing sudden death. A number of other substances
can also clog the lungs but they are much more rare:
fat embolism, amniotic fluid embolism , air embolism
(iatrogenic - caused by invasive medical procedures).

Pulmonary arterial hypertension: elevated pressure in the
pulmonary arteries. It is most commonly idiopathic (i.e. of
unknown cause) but it can be due to the effects of another
disease, particularly COPD. This can lead to a strain on the
right side of the heart, a condition known as cor pulmonale.

Pulmonary edema: leakage of fluid from capillaries of the
lung into the alveoli (or air spaces). It is usually due to
congestive heart failure.

Pulmonary hemorrhage: inflammation and damage to
capillaries in the lung resulting in blood leaking into the
alveoli. This may cause blood to be coughed up. A
pulmonary hemorrhage can be due to auto-immune
disorders such as Wegener's Granulomatosis and
Goodpasture's syndrome.
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