This article provides an overview of the basic structure and function of the respiratory system.
Functionally, the respiratory system structures can be classified into:
Conducting zone and Respiratory zone
The conducting zone; whereby air can move in a continuous passageway includes:
- Nose
- Pharynx
- Larynx
- Trachea
- Bronchi
- Bronchioles
The respiratory zone; is found deep inside the lungs where inhaled oxygen can be exchanged for carbon dioxide and includes:
- Respiratory bronchioles
- Alveolar ducts
- Alveoli
Anatomically, the respiratory system structures are divided into:
Upper respiratory tract and Lower respiratory tract
The upper respiratory tract is located in the head and neck and consists of the:
- Nose
- Pharynx
- Larynx
Nose:
Regions of the nose include the external nose and the nasal cavity. Air moves from the nostrils to the back of the nasal cavity where it exits through the posterior nares. The function of the nasal cavity is to clean, warm and dampen the air that enters so that it can travel throughout the body.
Regions of the Pharynx:
Air moves into the nasal cavity through the nostrils (nasopharynx). The oropharynx opens into the oral cavity which encloses the lips, teeth, cheek, hard and soft palates, tongue and tonsils. Extending from the tip of the epiglottis to the glottis and the esophagus is the laryngopharynx and positioned in the anterior neck is the larynx.
Larynx:
The larynx is a passageway between the pharynx and the lower airway structures. It is a short tube made up of supportive cartilage, ligaments, muscle and mucosal lining. The supportive cartilage prevents food and drink from entering the larynx while swallowing.
The lower respiratory tract is located in the chest and makes up the:
- Trachea
- Bronchial tree
- Lungs
Air passes from the larynx to the lungs (trachea).The trachea divides into the right and left primary bronchi (bronchial tree) and the large pair of spongy organs (lungs) are used for respiration.
Trachea:
Also known as the windpipe, the trachea is a 10-12cm tube that runs through the lower neck and chest. The wall of the trachea is made of hyaline cartilage which enables the trachea to stay open so that air can be conducted between the larynx and primary bronchi.
Bronchial tree:
The bronchial tree consists of a primary, secondary (lobar) and tertiary bronchi (segmental bronchi). The trachea splits into the right and left bronchi at the level of the sternal angle. The secondary bronchi forms when the primary bronchus enters the lung; and conducts air directly to one of the five lobes within the lung. Tertiary bronchi derive from the secondary bronchi and conduct air to and from the bronchial segment. There are 8 bronchial segments in the left lung and 10 in the right lung.
Resource: An Online Examination of Human Anatomy and Physiology. GetBodySmart:Interactive by ConceptCreators Inc
