Respiratory System
Structures & Functions
• The organs of the respiratory system include
– Nose
– Pharynx
– Larynx
– Trachea
– Bronchi
– Lungs
• Accessory organs
– Diaphragm
– Thorax
Structures & Functions
• The process of respiration involves the
inspiration of air that contains O2 for use by the
cells of the body and the expiration of CO2,
which is a waste product from the cells of the
body.
• The respiratory system relies on the circulatory
system to complete the respiratory cycle.
Structures & Functions
• O2 is inhaled into the lungs and transported by
the blood.
• The blood then transports waste products back
to the lungs to be exhaled.
Nose
• Naso or rhino mean nose
• Acts as an entrance for air and exit for CO2.
• Mucous membrane lines the nose.
▫ Acts as a filter for dust and other foreign matter
• The nose also warms and moistens the entering
air.
• Contains olfactory receptors.
• Bloodhound
Nose
• The nostrils are paired external openings to the
airways.
▫ Very in pliability and expandability
 Horse – expandable nostrils
 Pig – rigid nostrils
Importance of Concha
• Responsible for bringing air temperature to an
acceptable level.
• Bulldog
Pharynx
• AKA the throat
• The upper portion of the pharynx is attached to the
base ok the skull and the lower portion unites with
the esophagus.
• Divided into three parts
– Nasopharynx
• Opening into the back of nasal chambers
– Oropharynx
• Opening into the back of the mouth
– Laryngopharynx
• Opening into the larynx and esophagus
Pharynx
• The pharynx is used by both the respiratory and
the digestive tracts as a passageway for air and
food
• Depending on the species, it may also have a role
in vocalization.
Larynx
• The larynx is commonly called the voice box and
is located just below the pharynx. (Adams apple)
• Firm cartilage structure at the opening to major
airways.
▫ Epiglottis
 a lid like cartilage structure that prevents food from
entering the airway during swallowing
 Main sound organ in mammals
Larynx
• The larynx contains the vocal folds
• Opening between the vocal folds is the glottis.
Trachea
• Series of cartilage rings joined by connective
tissues.
▫ Rings are C shaped, not complete circles
Why?
• Supports a rigid airway, allows for movement.
Trachea
• Lined with epithelium containing cilia.
▫ Particles that get past the nasal membranes are
caught in the cilia.
▫ Worked toward pharynx where it is swallowed.
Trachea
• Trachea branches into 2 bronchi.
▫ Right and left lung
• Trachea
▫ Bronchus
 Bronchioles
 Alveolar Sacs
▫ Aveoli
RESPIRATORY RATES OF VARIOUS
ANIMALS
HORSE: 10-14 BPM MEAN 12
DAIRY COW: 26-35 BPM MEAN 29
PIG: 32-58 BPM MEAN 40
DOG: 18-34 BPM MEAN 24
CAT: 20-40 BPM MEAN 31
SHEEP: 20-34 BPM MEAN 25