Respiratory System and Respiratory Disorder

The human respiratory system is not as easy as inhaling oxygen and exhaling carbon dioxide, but it has to work properly to keep us alive. It occurs at the cellular level (internal respiration) and organismic level (external respiration). Internal respiration involves the breakdown of a complex compound into a simple molecule with the release of energy and external respiration involves inhaling oxygen and exhaling carbon dioxide.

The respiratory system of humans:

It involves two tracts, the upper and lower respiratory tract.

Upper Respiratory tract:

It includes nose/nostrils, nasal cavity, sinuses, throat (pharynx), and voice box (larynx).

• Nose or nostrils:

The externally visible part and main entrance and exit for respiration are through the nose. It contains bone, cartilage, and fatty tissues. The external opening of the nose is called the nostrils.

• Nasal cavity:

Nostrils flow into inner hollow spaces called a nasal cavity, separated into two which are separated by the nasal septum. Both nostrils and nasal cavity are lined with ciliated mucous membranes which help to trap foreign particles including dust and microorganisms.

• Sinuses:

Sinuses are holes in the skull between the facial bones. It produces mucus to moisturize inside of the nose.

• Pharynx (Throat):

It is a part of both the respiratory and digestive systems. It is divided into three sections: the nasopharynx, the oropharynx, and the laryngopharynx.

• Larynx (Voicebox):

It is present below the pharynx and top of the trachea. Composed of muscle and three cartilage (thyroid cartilage, epiglottis, and cricoid cartilage). Thyroid cartilage contains Adam’s apple, Epiglottis allows air to enter the larynx and prevents food and liquid from entering in air passage whereas cricoid cartilage forms a major part of the larynx. Two vocal cords inside the larynx are responsible for speech.

Lower respiratory tract:

It includes the trachea, bronchi, alveoli, and lungs.

• Trachea:

The trachea consist of dense regular tissue and smooth muscle with 15–20 C-shaped pieces of cartilage prevent from collapsing extended from the larynx to the lungs.

• Bronchi:

The trachea is divided into two smaller left and right primary bronchi. It is further divided into secondary bronchi within each lung and then into tertiary bronchi finally giving rise to bronchioles, where cartilage is replaced by muscular walls which help change the size of the tube. Bronchioles are subdivided to form terminal bronchioles.

• Alveoli:

Terminal bronchioles are divided into the alveolar ducts, they end at a tiny air-filled chamber called alveoli. It is a grape-like sac responsible for gas exchange.

• Lungs:

Lungs are the main organ of respiration, responsible for inhaling oxygen and exhaling carbon dioxide.

Respiratory Disorders

A respiratory disorder can be a short or long-term illness.

Upper Respiratory Tract Infection:

It includes sinusitis, etc.

• Sinusitis:

Inflammation of nasal sinuses is caused by cold and wet climates. Symptoms are fever, nasal obstruction, raspy voice, pus-like nasal discharge, loss of sense of smell, facial pain, or headache. It may be acute(symptoms last 2–8 weeks) or chronic(symptoms last longer). If bacterial infection antibiotic or sulpha drugs are prescribed.

Lower Respiratory Tract Infection:

It includes tuberculosis (TB), etc

• Tuberculosis (TB)

It is a highly contagious chronic bacterial infection of the lungs. It is caused by Mycobacterium Tuberculosis. Symptoms are low-grade fever usually in the evening, night sweating, weight loss, depression, weakness, and dry cough with sputum. Taking medicine for 9 months regularly can cure TB disease.

Disorders of lungs:

There are many disorders that affect the lungs, one of which is lung cancer.

• Lung Cancer:

Cancer is a malignant tumor that develops due to uncontrolled cell division. Smoking is the main cause of lung cancer. Symptoms appear to be thickening and callusing (overgrowth) of the cell lining the bronchi. Treatment is to remove a lobe or the lung completely before secondary growth (pneumonectomy), chemotherapy, or radiotherapy.