The respiratory system has an upper and lower tract. The upper tract includes the nose, which filters and humidifies air using nasal cavities divided by conchae bones. The lower tract includes the larynx and lungs. The larynx contains cartilages like the thyroid and cricoid that protect the trachea and allow vocalization. The lungs are divided into lobes that vary between species but facilitate gas exchange in the respiratory surface area.

1. By. DR. NOOR
ORGANS OF
RESPIRATORY SYSTEM
OF ANIMALS

3. UPPER RESPIRATORY TRACT (NOSE & NASOPHARYNX)
1. NOSE (GREEK-RHIN, LATIN-NASUS)
The nose (Greek, “rhin”) consists of:
• the external nares and their associated nasal cartilages
• the nasal cavity with the nasal meatus and conchae and
• the paranasal sinuses

4. The nose is formed by
• the nasal bones dorsally,
• the maxillae laterally
• the palatine processes of the incisive bones, the maxillae and the
palatine bones ventrally
• Caudally it is limited by the cribriform plate of the ethmoid bone.

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8. PTERYGOID BONE

9. Nose …..
• Ventrally it is continuous with the nasopharynx
• The median septum is the rostral continuation of the crista
galli of the ethmoid bone and consists of hyaline cartilage,
which divides the nasal cavity into the left and right sides; the
caudal part of this cartilage ossifies with age

10. FOSSA
In anatomy a fossa (/ ˈfɒsə /; PL: fossae (/ ˈfɒsiː /
or / ˈfɒsaɪ /); from Latin fossa, "ditch" or "trench")
is a depression or hollow usually in a bone, such
as the hypophyseal fossa (the depression in the
sphenoid bone.

12. TP
MD
OC
PB
MAXILLA
ZB
FB
NB
IB
LB
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16. Dental formula of Dog
2 x (3 1 4 2 / 3 1 4 3) = 42 teeth
2 x (I C P M / I C P M)

17. CONCHA
It helps to filter and humidify the air that we breathe. The nasal conchae (plural
of concha) are also sometimes called turbinates. The inferior nasal conchae are a pair of
bones, with one concha on either side, that separates the middle and lower nasal meatus,
or nasal cavity. They are often described as being "spongy" bones
MEATUS
In anatomy, a meatus ( / miːˈeɪtəs /, mee-AY-təs ), plural "meatus" or "meatuses", is
a natural body opening or canal. the internal auditory meatus, a canal in the temporal
bone of the skull the urinary meatus, which is the opening of the urethra, situated on the
glans penis in males, and in the vulva in females

19. group of bony sheets
The ectoturbinates are more
numerous and smaller than the
endoturbinates

21. NASAL CARTILAGES (CARTILAGINES NASI)
• The external nares are supported by the nasal cartilages, which are variable in
form, size and number depending on the species
• The lateral nasal cartilages are attached to the rostral end of the nasal septum
from which they extend ventrally and dorsally
• They determine the form of the opening of the nostril.
• The dorsal and ventral lateral nasal cartilages are in contact with each other in
all domestic species except the horse.
• Depending on the species several accessory nasal cartilages may arise from the
lateral nasal cartilages

24. Alar = wing-shaped
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27. • In the horse the dorsal nasal cartilage does not project far and the
ventral nasal cartilage is either indistinct or absent
• Instead, the alar cartilages divided into a plate (lamina) dorsally and a
horn support the large and widely spaced nostrils.
• The lateral walls of the nostrils are not supported by cartilage, thus
the margins of the nostrils remain very mobile and allow the opening
to be dilated when necessary.
• The alar cartilages account for the characteristic comma shape, which
divides the nostril into the ventral, so-called true nostril leading to
the nasal cavity, and the dorsal or false
nostril leading to a skin-lined diverticulum
• it is essential when passing a nasogastric tube to guide it ventrally

29. Nasal cavities (cava nasi)
• The nasal cavity extends from the nostrils to the cribriform plate of the ethmoid bone
• it is divided by the nasal septum into right and left sides. The nasal conchae project into
the interior of the nasal cavity and serve to increase the respiratory surface area
• Dogs have highly developed olfactory senses their nasal conchae are more complex
further increasing the olfactory surface area. This increase in surface area, together with a
higher number of olfactory receptor cells, accounts for the excellent olfactory sense of
the dog compared to humans.
• Caudoventrally the nasal cavity communicates with the nasopharynx through the
choanae.

30. Nasal conchae (conchae nasales)
• The nasal conchae are cartilagenous or ossified scrolls covered
with nasal mucosa that occupy most of the nasal cavity
• have complicated and species-specific arrangement
• The first endoturbinate (endoturbinale I) is the longest and most dorsal turbinate and extends furthest
into the nasal cavity.
• It forms the osseous base of the dorsal nasal concha
• The second endoturbinate (endoturbinale II) is adjacent to the first and forms the bony part of the
middle nasal concha
• In dog, the second to fourth endoturbinates are especially well-developed
• Endoturbinates form dorsal and middle nasal concha
• the ventral nasal concha is part of the maxilla

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35. Nasal meatuses (meatus nasi)
• The major conchae divide the nasal cavity into a series of clefts and
meatuses which branch out from a common meatus near the
nasalseptum.
There are three nasal meatuses in the domestic mammals
● dorsal nasal meatus (meatus nasi dorsalis),
● middle nasal meatus (meatus nasi medius) and
● ventral nasal meatus (meatus nasi ventralis)

36. • The dorsal nasal meatus is the passage between the roof of the
nasal cavity and the dorsal nasal concha. It leads directly to the
fundus of the nasal cavity and channels air to the olfactory mucosa
• The middle nasal meatus is between the dorsal and the ventral nasal conchae and
communicates with the paranasal sinuses. (Paranasal sinuses are a group of four paired air-filled
spaces that surround the nasal cavity. The maxillary sinuses are located under the eyes; the frontal sinuses are
above the eyes; the ethmoidal sinuses are between the eyes and the sphenoidal sinuses are behind the eyes. The
sinuses are named for the facial bones and sphenoid bone in which they are located)
• The ventral nasal meatus is the main pathway for airflow leading to the pharynx and is
situated between the ventral nasal concha and the floor of the nasal cavity
• The common nasal meatus is the longitudinal space on either side of the nasal septum.
It is communicate with all the other nasal meatus.
• The pharynx can be accessed by the passage of nasogastric tubes and endoscopes
through the widest point, between the ventral and common meatus.

37. Dental formula of Dog
2 x (3 1 4 2 / 3 1 4 3) = 42 teeth
2 x (I C P M / I C P M)

40. PRACTICAL

44. Definitions
Concha = any of several thin, scroll-like (turbinate) bones in the sides
of the nasal cavity.
Meatus = a passage leading to the interior of body cavity
Alar = resembling a wing-shape

45. PRACTICAL

46. Paranasal sinuses
• diverticula of the nasal cavity
• form air-filled cavities between the external and internal lamina
of the bones of the skull

47. Maxillary sinus
• The is contained within the caudal part of the maxilla
• In the horse, a bony septum divides the maxillary sinus
in a smaller rostral compartment and a larger caudal
• floor of the maxillary sinuses is indented by the dental alveoli of
the last three cheek teeth.
• Since only a thin bone plate separates the tooth roots from the paranasal sinus,
periapical infection can easily penetrate the bone and cause sinusitis.

48. …. maxillary sinus
• The caudal maxillary sinus communicates directly or indirectly with all the other
paranasal sinuses. This anatomical arrangement accounts for the spread of
infection throughout the paranasal sinuses in the
horse
• The maxillary sinus of carnivores is better termed the maxillary recess since it is a
diverticulum of the nasal cavity at the level of the medial nasal concha rather than
a real air-filled cavity between the internal and external laminae of
the bones of the skull.

49. The frontal sinus
• is contained within the frontal bone and usually communicates with the
middle nasal meatus
• In the horse it is continuous with the dorsal conchal sinus and is therefore
referred to as the concho-frontal sinus
• In ruminants it extends into the cornual process of the frontal bone, which
accounts for the high incidence of inflammation of the frontal sinus after
surgical dehorning

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54. Palatine and Sphenoid sinuses
• in the horse the palatine and sphenoid bones are also pneumatized
• The union of the palatine and the sphenoidal sinus results in the combined sphenopalatine sinus,
which communicates with the caudal maxillary sinus

55. Lower respiratory tract
Larynx
• bilaterally symmetrical, tube-shaped musculo cartilagenous organ
• that connects the pharynx to the trachea
• Prevents aspiration of foreign material
• vocalisation

56. Cartilages of the larynx
The skeleton of the larynx is composed of the following bilaterally symmetrical
laryngeal cartilages
1. epiglottic cartilage (cartilago epiglottica), forming the base of
the epiglottis,
2. thyroid cartilage (cartilago thyroidea),
3. arytenoid cartilages (cartilagines arytenoideae) and
4. cricoid cartilage (cartilago cricoidea)

57. PRACTICAL

59. Epiglottis (epiglottis)
• The epiglottic cartilage (elastic cartilage) forms the base of the
epiglottis
• The epiglottis resembles a leaf with a small stalk (petiolus) and a
large blade.
• Its free apex points rostrally and is sharp-pointed in carnivores and
the horse and more rounded in ruminants and the pig.
• The epiglottic cartilage consists of elastic cartilage.

60. Thyroid cartilage
• hyaline cartilage
• may ossify with advancing age
• forms the lateral walls and the floor of the larynx
• It has two lateral plates and a ventral body
• Each lamina is expanded dorsally to form rostral and caudal
processes
• The rostral process articulates with the hyoid bone, the caudal
process with the cricoid cartilage

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62. Arytenoid cartilages
• hyaline cartilage and are the only paired laryngeal cartilages
• forming the major part of the roof of the larynx

63. Cricoid cartilage (hyaline cartilage)
• The cricoid cartilage forms a complete ring at the caudal end of
the larynx
• has the shape of a signet ring
• Has an expanded dorsal plate (lamina) and a narrower ventral
arch
• dorsal plate articulates with the arytenoid cartilages
• while the ventral arch articulates with the caudal processes of
the thyroid cartilage.

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66. Comparison of lung lobes

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