Breathing is formally called
Respiration
For complete exchange of oxygen (O2)
and carbon dioxide (CO2) in respiration, four steps occur simultaneously:
Ventilation
External Respiration
Gas Transport
Internal Respiration
This is what most of us think of as breathing.
Ventilation
It is the movements of the thorax and certain muscles that cause air to go into and out of our lungs.
Ventilation
Oxygen enters the blood in the lungs and CO2 exits the blood in the lungs.
External Respiration
Carbon dioxide and O2 are circulated in the blood to and from tissues.
Gas Transport
Gas exchange with the tissues involves the exit of O2 from blood to move into the tissues, while CO2 exits the tissues to enter the blood.
Internal Respiration
The respiratory system performs
the following functions:
Regulation of blood pH
Production of chemical mediators
Voice Production
Olfaction
Protection
The respiratory system can alter
blood pH by changing blood CO2 levels.
Regulation of blood pH
The lungs produce an enzyme called angiotensin-converting enzyme (ACE), which is an important component of blood pressure regulation
Production of chemical mediators
Air moving past the vocal folds makes
sound and speech possible.
Voice Production
The sensation of smell occurs when airborne molecules are drawn into the nasal cavity
Olfaction
The respiratory system provides protection against some microorganisms by preventing them from entering the body and removing them from respiratory surfaces.
Protection
There are seven structures that make up the respiratory system:
The upper respiratory tract consists of the
External Nose
Nasal Cavity
Pharynx and its associated structures
Larynx
Lower respiratory tract consists of the
Trachea
Bronchi and smaller bronchioles
Lungs
The respiratory system can be classified in two ways:
Structurally and functionally
Structurally, the respiratory system is divided into the
Upper Respiratory Tract
Lower Respiratory Tract.
Functionally, the respiratory system is divided into two regions.
Conducting Zone
Respiratory Zone
is exclusively for air movement and extends from the nose to the bronchioles.
Conducting Zone
is within the lungs and is where gas exchange between air and blood takes place.
Respiratory Zone
The conduction zone structures are well adapted for the
Movement
Cleaning
Warming
Humidification of air
or nasus, consists of the external nose and the nasal cavity.
Nose
is the visible structure that forms a
prominent feature of the face.
External Nose