Monthly Archives: March 2014

The Respiratory System

RESPIRATORY SYSTEM

WHAT IS RESPIRATORY SYSTEM: 

The respiratory system is a group of organs that is involved in the exchange of oxygen and carbon dioxide in your body system.

FUNCTIONS OF RESPIRATORY SYSTEM:

  1. The Respiratory System helps in nourishing your body with oxygen and eliminate carbon dioxide.
  2.  helps regulate blood pH and body temperature
  3. The Respiratory System also helps in vocalization.  The larynx or voice box  contains 2 vocal cords, which vibrate when air passes by them thus producing a sound.

STRUCTURES OF RESPIRATORY SYSTEM:

I. The Upper Respiratory System (the upper airway) is a collapsible tube, which includes:

Nasal Cavity or the nose:
Air is breathe in through the nose. The air  is filtered out for dust and foreign bodies, warmed and moistened by the tiny hairs called cilia and the  nasal mucosa.

Pharynx or the throat:
Pharynx is shaped like a cone, is part of the respiratory system and also of the digestive  system. Pharynx is situated posterior to the nasal cavity and mouth and superior to the esophagus and larynx. In the Respiratory System it acts as a passageway for air on it’s way to the lungs.  Pharynx is divided into three parts:

  1.  Oropharynx – The part of the throat that is behind the mouth (oral cavity)
  2. Nasopharynx –  The part of the thraot that is at the back of the nose (nasal cavity).
  3. Laryngopharynx – The part of the throat that is at the back of the larynx (voice box).

Larynx or the voice box :
The larynx is  located between the pharynx and the trachea. Its surrounding wall of  thyroid cartillage  formed an angle called Adam’s apple. It holds the vocal cords  which are responsible in producing sounds.

II. The Lower Respiratory System  (the lower airway):

Trachea or the wind pipe : It is a tubelike structure that connects the larynx to the lungs, a passageway for air. It has approximately 16- 20 C-shaped cartilaginous rings. The cartilage rings give the trachea protection and resistance against the pressure of air flow.

Bronchi: The bronchi are 2 tubes that branch from trachea.

1. The left main bronchus  (longer than the right bronchus) leads air to the left lung.
2. The right main bronchus  (shorter and wider than the left bronchus) direct air into the right lung.  The structure of the right main bronchus made them more susceptible with foreign body dislodging.

The bronchi become smaller and thinner branches as they get closer to the lungs and then become non cartilaginous branches called bronchioles.

Lungs: The lungs are the most vital organ  of the respiratory system. They are a pair of spongy, air-filled organs located on both sides of the chest (thorax). They are responsible for the  gas exchange process, supplying oxygen from the tiny air sacs( alveoli) in  the lungs to the blood , at the same time releasing carbon dioxide from blood to the tiny air sacs. Carbon dioxide leaves the body when we exhale.

 

THE ROLE OF THE DIAPHRAGM IN BREATHING:

The diaphragm aids respiration by contracting during inhalation and exhalation. When you inhale, the diaphragm contracts downward ,  increases the volume of the chest cavity, air and oxygen is drawn into your  lungs, allowing the lungs to inflate. When you exhale, the lungs release carbon dioxide, the diaphragm relaxes, allowing the lungs to deflate, thus reduces the space in the chest cavity

 

THE FLOW OF AIR IN THE RESPIRATORY SYSTEM:

AIR—>> NOSE–>> THROAT(pharynx)—>> LARYNX (voice box)—>>

TRACHEA—>> RIGHT BRONCHUS AND LEFT BRONCHUS—>>

BRONCHIOLES—>>ALVEOLI in the LUNGS  ( inflate during inhalation and deflate

during exhalation).

 

HOW THE BLOOD FLOW THROUGH YOUR LUNGS FOR OXYGENATION:

From the  heart—>> deoxygenated blood  travels—>> through the pulmonic valve —>>

it enters your lungs. This is called the pulmonary circulation. From your pulmonic valve,

the blood—>> travels to the pulmonary artery  to tiny capillary vessels into your  lungs

for gas exchange.  Here, oxygen travels from the tiny air sacs in the lungs, through the

walls of the capillaries —>>  blood  oxygenation takes place. Simultaneously, carbon

dioxide, a waste product of metabolism, passes from the blood into the air sacs. Carbon

dioxide leaves the body during exhalation. The oxygenated blood travels back to your

heart->>enters the left atrium via pulmonary veins.

 

RESPIRATORY SYSTEM CONDITIONS:

Asthma: A common respiratory disorder . It is the  inflammation of bronchi and bronchioles, which causes swelling and narrowing of the  airways. Symptoms include shortness of breath, wheezing, chest tightness and coughing. Family history of asthma, respiratory infections in early childhood, obesity, medications, air pollution, exposure to tobacco smoke, factory fumes, cleaning solvents, infections, pollens, foods, cold air, exercise, chemicals, are some of the  factors that  act together to cause asthma or are risk factors that trigger the symptoms of asthma. Avoidance of precipitating factors can be helpful.

 

Chronic obstructive pulmonary disease (COPD) is a lung disease that causes difficulty of breathing. COPD is incurable, but treatments can slow progression of the lung damage. Tobacco smoking is the most common cause of COPD,  the other causative factors are exposure to air pollutants and genetics. Avoiding the causing factors can decrease the risk of complications.

There are two main types of COPD:

1. Emphysema: is a form of chronic obstructive pulmonary disease (COPD where the air sacs (alveoli) in your lungs are  destroyed  and become over-expanded, causing shortness of breath  and sometimes breathlessness. The larger the air sacs are, the lesser movement of oxygen into the blood thus limiting the oxygen and carbon dioxide exchange. Treatment may delay the worsening of emphysema, and decrease the risk of complications but it can’t repair damage. Main symptom is shortness of breath that is gradually progressing. Heavy cigarette smoking attributes most of  emphysema cases.

2. Chronic Bronchitis:  is a type of Chronic Obstructive Airway Disease that is recurrent and  can last a long time. It is characterized by  the presence of cough with mucus that usually lasts for several months. Cigarette smoking, is the most common cause. Second hand smoke, exposure to air pollutants  and chemical respiratory irritants are also some of the precipitating factors. Symptoms include persistent cough with sputum that lasts for 3 months or more, shortness of breath, wheezing, chest tightness, fever, fatigue or malaise. Avoiding the causative factors may help with the treatment.

 

Acute Bronchitis: An infection of the bronchi, usually caused by a virus. Often a person gets acute bronchitis after having a viral infection  such as a cold, RSV, rhinovirus or the flu. It can also be caused by exposure to tobacco smoke. Bacteria are less common  cause of acute bronchitis

Bronchitis normally starts with a dry cough (the most common symptom of acute bronchitis) that progresses to  productive cough and may bring up mucus. Other symptoms such are low grade fever, chest tightness, fatigue and malaise can get better in few days . But the cough may last for several weeks after the infection has cleared.

Many doctors advise smokers should quit smoking completely not to make the bronchitis worse and to allow their lungs to recover from the built up tars.

 

Lung cancer: is a disease characterized by uncontrolled  growth of abnormal cells in  tissues of the lung. The most common cause of lung cancer is cigarette smoking,  but can affect non -smokers too.  Nonsmokers are often associated to a combination of genetic factor, secondhand smoke, exposure to asbestos, and air pollution.

Signs and symptoms that may suggest lung cancer include:

  •  Chronic raspy coughing
  • Coughing out blood or blood streaked sputum
  • Chronic bronchitis or pneumonia
  • Increasing shortness of breath
  • Hoarse voice
  • wheezing,
  • persistent chest pain
  • Fatigue, weakness,
  • loss of weight and appetite,
  • intermittent fever,  and body pain
  • Difficulty swallowing

 

Pneumonia: is an infection of the lung caused by virus or bacteria, affecting the tiny air sacs called alveoli. Common symptoms include a chest pain, shaking, chills, fever, dry cough, and difficulty of breathing. Pneumonia can be treated at home. But some people can become very ill that may require them to be admitted in the hospital.

***Vaccines are available to prevent certain types of pneumonia.

 

Bronchiectasis: The airways (bronchi) become permanently dilated, usually after recurrent infections, resulting in airway obstruction and impaired abilty to clear out secretion. Extra mucus builds up, allowing bacteria to grow thus causing lung infection.

Coughing, with foul smelling large amounts of mucus, is the main symptom of bronchiectasis.

Bronchiectasis can be present at birth (congenital bronchiectasis) but is most often acquired.

 

Cystic Fibrosis:(CF), also known as mucoviscidosis, is a genetic condition in which mucus does not clear easily from the airways, leading to thick, viscous secretions to build up in the lungs. This collection of sticky mucus results in recurring lung infections and damaged lungs.

In CF, the sweat  become very salty, due to salt and water imbalance, causes

Cystic fibrosis is a hereditary disease wherein a child must inherit two faulty CFTR genes, and can only get it if his or her parents are both a carrier. If a child inherit one defective CFTR gene and one normal CFTR gene he or she will be a  CF carrier,  in which case the child have no symptoms of cystic fibrosis, but can pass the faulty gene on to his or her children.

***Cystic Fibrosis Transmembrane Conductance Regulator, also known as the CFTR gene

Diagnostic test for CF:

  • Blood Test and
  • Sweat Test

 

Tubercolosis: is an infectious lung disease caused by the bacteria Mycobacterium tuberculosis.  People with active TB infection can transmit the disease through the air. Airborne precaution is recommended.

Common symptoms of TB:

  • fatigue
  • shortness of breath
  • coughing that lasts for several weeks
  • coughing up blood
  • chest pain
  • unexplained weight loss
  • fever
  • night sweats
  • chills
  • loss of appetite.

The diagnosis of TB involves skin tests, chest X-rays, sputum analysis (smear and culture),

 

Pertussis (whooping cough): is an acute contagious infection of the airways (bronchi) caused by bacteria Bordetella pertussis, causing persistent cough. Droplet precaution is recommended. Immunization with pertussis vaccine can prevent infants and young children from getting whooping cough. A booster vaccine  is recommended for adolescents and adults to prevent pertussis. Methods used in laboratory diagnosis include culturing of nasopharyngeal swabs.

 

COMMON DIAGNOSTIC TESTS FOR RESPIRATORY DISEASES INCLUDE :

  • Chest x-ray
  • Pulmonary function test
  • CT scan.
  • Arterial Blood Gases
  • Complete Blood Count

 

*** Many types of  Respiratory Disease can be prevented with a healthy lifestyle .