1. The respiratory system

2. Respiratory System Function
Major Functions
Upper respiratory system:
Air conditioning
Defense against pathogens
Lower respiratory system:
Speech & other respiratory sounds
Gas exchange (Supplies body with oxygen and Disposes of carbon dioxide )
Maintenance of homeostasis, e.g. pH

3. Organs of the Respiratory System
Divided into:
Conducting zone – respiratory passage which serve as conduits that carry air to the sites of gas exchange
Serve to filter, humidify, and warm the incoming air
Respiratory zone – the actual site of gas exchange in the lungs
Respiratory bronchioles, alveolar ducts, alveolar sacs – contain alveoli

4. Functional Anatomy of the Respiratory System
Respiratory organs
Nose, nasal cavity, and paranasal sinuses
Pharynx, larynx, and trachea
Bronchi and smaller branches
Lungs and alveoli

5. THE NOSE parts: Nasal cartilages External nose Internal nasal cavity
Functions:
Provides an airway for respiration
Moistens and warms air
Filters inhaled air
Houses olfactory receptors

6. The External Nose Rostral structure protruding slightly from the face
Size variation due to differences in nasal cartilages.
The nostrils (cranial nares) are large and widely spaced.
The upper part of the opening leads to a blind nasal diverticulum which occupies the nasoincisive notch.
The lower part leads to the nasal cavity
it is essential when passing a stomach tube to ensure that it is guided into the lower par

8. External nares – nostrils Lies in and posterior to the external nose
The Nasal Cavity
External nares – nostrils
Lies in and posterior to the external nose
Divided by – nasal septum.
Continuous with nasopharynx
Internal nares
posterior nasal apertures (choana)
Roof – Ethmoid and sphenoid bones
Floor – hard palate.

9. The nasolacrimal duct : - It is an opening found on the floor about 5cm internal to the entrance near the mucoutaneous junction - it has more than one opening - Ventral nasal meatus.

10. Project medially from each lateral wall of the nasal cavity.
Nasal Conchae
Project medially from each lateral wall of the nasal cavity.
Dorsal conchae
Ethmoid conchae
Ventral conchae
Creates turbulence which increases the amount of contact between nasal mucosa and inhaled air
Function: to filter, heat and moisten air

12. Paranasal Sinuses
The paranasal sinuses are diverticula of the nasal cavity that excavate the skull bones largely after birth.
The separation of the inner and outer tables of the bones alters the conformation of the head
and is specially striking in pigs and cattle, in which certain sinuses eventually extend dorsal and even caudal to the cranial cavity.

13. Paranasal Sinuses
The sinuses retain their connections with the nasal cavity
these openings are generally narrow a relatively slow exchange of air occurs
The narrowness and locations of the openings make them prone to blockage when the mucosa is thickened by inflammation or congestion.
Not all the sinuses are of equal importance.

14. The function The function of the sinuses is obscure Offer some thermal
Mechanical protection to the orbit and nasal and cranial cavities
Enlarge the skull areas available for muscular attachment without unduly increasing weight,
Affect the resonance of the voice.

15. All species have frontal and maxillary systems
neither communicating with its contralateral counterpart.
The frontal system consists of one or more spaces within the bones at the border between the nasal and cranial cavities.
In most species the various frontal compartments open separately into ethmoidal meatus in the nasal cavity
in the horse the frontal sinus communicates with the nasal cavity indirectly via the caudal maxillary sinus.

16. The maxillary sinus system occupies the caudolateral part of the upper jaw, above the caudal cheek teeth
In some species it sends extensions, variously described as separate sinuses or as diverticula
into the hard palate
the sphenoid bones
the medial aspect of the orbit
the ventral concha.

17. In the horse the maxillary sinus is divided into caudal and rostral parts, both connected to the middle nasal meatus
In the dog the cavity communicates freely with that of the nose and is known as the maxillary recess.

18. EQUINE
On each side there are frontal, caudal maxillary, and rostral maxillary sinuses of importance
sphenopalatine and ethmoidal spaces of less account.
the frontal sinus communicates with the nasal cavity indirectly via the caudal maxillary sinus.
The two maxillary sinuses together occupy a large part of the upper jaw, where they have a critically important relationship to the embedded portions of the caudal cheek teeth.
They share a slit like communication (nasomaxillary opening) with the middle meatus of the nasal cavity
The frontal sinus occupies the dorsal part of the skull medial to the orbit.
It overlaps both cranial and nasal cavities.
Since it also occupies the closed part of the dorsal concha, it is more correctly known as the conchofrontal sinus

19. BOVINE, OVINE, CAPRINE
The paranasal sinus system is very poorly developed in the young calf, Even in the mature animal, the maxillary compartment continues to adjust to extrusion of the cheek teeth.
The complete set of sinuses is very complicated.
It comprises:
Frontal compartments within the bones of the cranial roof and side walls;
Platomaxillary complex within the caudal part of the hard palate and the face, both before and below the orbit;
Lacrimal sinus within the medial orbital wall;
Sphenoidal sinuses that extend past the orbit into the rostral part of the cranial floor
Conchal sinuses within the nasal conchae.

20. Funnel-shaped passageway.
The Pharynx
Funnel-shaped passageway.
Connects nasal cavity and mouth to the larynx dorsally and the esophagus ventrally.
Divided into three locations.
Nasopharynx, oropharynx, and laryngopharynx

22. The Nasopharynx
Superior to the point where food enters
Only an air passageway
Closed off during swallowing by soft palate
Contains the opening to the auditory tube

23. The Oropharynx
Posterior to oral cavity, extends from soft palate to the epiglottis
Passageway for food and air

24. The Laryngopharynx
Dorsal to the larynx and continuous with the esophagus
Extends from the epiglottis to the larynx
Passageway for both food and air

26. Extends from the level of the 2nd to 3th cervical vertebra
The Larynx (Voice Box)
Extends from the level of the 2nd to 3th cervical vertebra
Cranially attached to the hyoid bone and opens into the laryngopharynx
Caudally is continuous with the trachea
Three functions
Voice production
Provides an open airway
Routes air and food into the proper channels

27. The larynx is the part that forms the connection between the pharynx and the tracheobronchial tree.
Position: the larynx can be found behind the mouth, below the pharynx.
Its position is altered when the animal swallows due to its connection with the hyoid apparatus and tongue.
The larynx's main function is to protect the rest of the respiratory tract and system as well as producing sound (vocalisation)

28. The Larynx is formed from the following cartilages
The Median Epiglottic Cartilage
The Thyroid Cartilage
The Cricoid Cartilage
A Pair of Arytenoid Cartilages

30. The Musculature of the Larynx
Extrinsic Laryngeal muscles; these pass between the larynx and pharynx, tongue, hyoid bone and sternum.
Intrinsic muscles; connect the laryngeal cartilages to each other.
They are all innervated by the recurrent laryngeal nerve.
There are 5 muscles:
Cricothyroideus,
Cricoarytenoideus Dorsalis
Cricoarytenoideus Lateralis
Arytenoideus Transversus
Thyroarytenoideus

31. The hyoid apparatus provides an attachment platform for the tongue and larynx. Hyoid bones are: stylohyoid (1), epihyoid (2), ceratohyoid (3), thyrohyoid (4), and basihyoid (5), the latter is the only unpaired hyoid bone.
Thyroid cartilage of the larynx (6), cricothyroideus m. (7), and the trachea (8).

32. Right: epiglottic cartilage (1), arytenoid cartilages (2), aryepiglottic fold (3), thyroid cartilage (4), cricoid cartilage (5), cricoarytenoideus dorsalis m. (6), trachea (7), and root of the tongue (8).
Left top: The left side of the larynx has been removed. Identify: thyroid cartilage (1), epiglottic cartilage (2), arytenoid cartilage (3), cricoid cartilage (4), cricoarytenoideus lateralis m. (5), cricoarytenoideus dorsalis m. (6)
Left bottom: thyroid cartilage (1), cricoid cartilage (2), cricothyroid ligament (asterisk), cricothyroideus m. (3), trachea (4), basihyoid bone (5), and ceratohyoid bone (6).

35. The Trachea
Descends from the larynx through the neck, into the mediastinum.
Divides into two main bronchi in the thorax .
Made up of C-shaped cartilage rings of hyaline cartilage, allow it to be flexible.
Made of 3 layers of membranes that contain mucus and help filter the air and allow for flexibility.

37. Bronchi in the Conducting Zone
Bronchial tree – extensively branching respiratory passageways within the lungs
Division of the trachea at T4/T7
Primary bronchi (main bronchi) – largest bronchi or conduits in the bronchial tree
Right main bronchi – wider and shorter than the left and more vertical (clinical important)

38. Bronchi in the Conducting Zone
Secondary (lobar) bronchi – each of which supply one lung lobe
Three-four on the right, Two on the left
Tertiary (segmental) bronchi
Branch into each lung segment
Overall, 23 orders of air passageways
Bronchioles – little bronchi, less than 1 mm in diameter
Terminal bronchioles – less than 0.5 mm in diameter

39. From Bronchi to Lungs
1 bronchi (enter lungs at hilus, complete cartilage rings)
2 bronchi (from now on cartilage plates)
3 bronchi
Bronchioles
Terminal bronchioles
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
Conducting portion
Respiratory portion

40. The Respiratory Zone
Consists of air-exchanging chambers – called alveoli
Begins at the terminal bronchioles
Respiratory bronchioles – branch from terminal bronchioles, have scattered alveoli protruding from their walls
Lead to alveolar ducts – walls consist almost entirely of alveoli
Lead to alveolar sacs – terminal clusters of alveoli
The opening from an alveolar sac into an alveolar sac is call an atrium “entrance chamber”

41. The Pleurae
Membranes that cover the lungs and line the pleural cavity.
A double-layered sac surrounding each lung
Parietal pleura
Visceral pleura
Pleural cavity - Potential space between the visceral and parietal pleurae, filled with pleural fluid

43. Gross Anatomy of the Lungs
Each lung roughly cone shaped, in contact with ribs – costal surface
Apex – the rounded, cranial tip of the lung
Base – the concave caudal surface that rests on the diaphragm
Hilus – medial indentation

44. Lungs in the dog

46. Gross Anatomy of the Lungs
Lobes – deep fissures separate the lungs into divisions
Left lung – 2 lobes
Right lung – 3-4 lobes
Lobule – smallest subdivision of the lung seen by naked eye

47. In horses the lungs are elongated and shallow
The left and right lungs are more equally in size than the other species
The difference between left and right manly in thickens ,the right lung more thicker than the left lung and it ha an accessory lob appended to the base
There is no evidence of lobation

48. The right lung consist of cranial,caudal and accessory lobes
The left lung consist of cranial and caudal lobes
The tow lungs are extensively joined by connective tissue caudal to the bifurcation of the trachea
At the junction between the trachea and the bronchi there are lymph nods which called (tracheobronchial lymph nodes)

49. -The pattern in sheep often varies between parts of the lung some show the connective tissue septa through the visceral pleura while others unmarked.
-The lung of cattle possess the usual roughly pyramidal shape .

50. Blood Supply and Innervation of the Lungs
Pulmonary arteries – deliver oxygen-poor blood to the lungs
Pulmonary veins – carry oxygenated blood to the heart
Innervation
Sympathetic, parasympathetic, and visceral sensory fibers
Parasympathetic – constrict airways
Sympathetic – dilate airways