Head & Neck Respiratory Organs PDF 2024

‫ﺑﺳم ﷲ اﻟرﺣﻣن اﻟرﺣﯾم‬ َ َ‫َوﻗُ ِل ا ْﻋ َﻣﻠُوا ﻓ‬ ‫ﺳﯾَ َرى‬ ُ ‫ﻋ َﻣﻠَ ُﻛ ْم َو َر‬ ُ‫ﺳوﻟُﮫ‬ َ ُ‫ﻠﻟاا‬ ‫ﱠ‬ َ ُ‫َوا ْﻟ ُﻣ ْؤ ِﻣﻧ‬ ‫ون‬...

‫ﺑﺳم ﷲ اﻟرﺣﻣن اﻟرﺣﯾم‬ َ َ‫َوﻗُ ِل ا ْﻋ َﻣﻠُوا ﻓ‬ ‫ﺳﯾَ َرى‬ ُ ‫ﻋ َﻣﻠَ ُﻛ ْم َو َر‬ ُ‫ﺳوﻟُﮫ‬ َ ُ‫ﻠﻟاا‬ ‫ﱠ‬ َ ُ‫َوا ْﻟ ُﻣ ْؤ ِﻣﻧ‬ ‫ون‬ ‫ﺻدق ﷲ اﻟﻌظﯾم‬ Respiratory System First Year 2024/2025 Prof. Dr. Ashraf El Sharaby Department of Anatomy & Embryology Organs of respiratory system 3  Organs of Respiratory System 1. Conducting portion: Part through which air passages to reach the lungs. It comprises nose, nasal cavity, nasopharynx, larynx, trachea, bronchi and bronchioles. 2. Respiratory portion: It comprises respiratory bronchioles, alveolar ducts, alveolar sacs and pulmonary alveoli. 3. Pumping portion: It comprises 2 pleural sacs and the skeleton of thorax (thoracic cage) and its muscles including diaphragm.  Functions of Respiratory System 1. Respiration: Conduct and pump inspired and expired air. It warms and adds moisture to the air to match the body temperature and humidity level body needs. It also protects (block) the body from harmful germs and irritant particles in the breathing air. 2. Production of voice: Air vibrates vocal cords, which makes sounds. 3. Olfaction (smell): Breathing in air moves its molecules past your olfactory nerve, which sends messages to your brain about the way something smells. 4. Balances level of acidity in your body: Too much CO2 lowers blood’s pH (acidic), So respiratory system helps maintain body acid-base balance by removing CO2.  The Nose The nose is the prominent structure located between the eyes and the upper lip. It serves as the entrance to the respiratory tract and contains the olfactory organ. It provides air for respiration, serves the sense of smell, conditions the air by filtering, warming, and moistening it, and cleans itself of foreign debris extracted from breaths.  The Nose What are the Parts of the Nose?  Nostrils: The external openings of the nasal passages through which air and scent molecules enter the nose.  Nasal Planum "nose pad”: The smooth, leathery surface surrounding the nostrils is known as the Nasal Vestibule: The initial portion of the nasal passages is lined with specialized hairs and mucus-producing glands that filter and humidify the air. Anatomical features of the nose: Nasal bones form the upper part of the nasal cavity and are important in shaping the horse’s nose. The bones forming the nose include incisive and nasal bones. Nasal openings are paired, and their shape vary according to the animal species. Shape of the nasal openings: Dog Cat Pig Cattle Sheep Horse  Nostrils of the horse Horses cannot breathe only through their mouths. This is because they have a long soft palate that obstructs breathing. Therefore, the nostrils are the main respiratory route for respiration. Anatomy of the nostrils of the horse:  The nasal openings are referred to as nares or nostrils and open into the nasal vestibule.  The external surface of the nostrils comprise normal pigmented skin, which is hairless or covered with short and tactile hair.  Each nasal opening is semilunar in outline (normal breath) and circular (extra respiration). It leads to true and false nostrils. Shape of the nostrils of the horse: Nasal plane of dog Nasal plane in dogs is Nasal more extensive, lacks plane hair, and has a clear Alar fold philtrum (deep groove dividing the nose with External nares the upper lip into 2 halves). Philtrum Nasal plane of the cat  Nasal cartilages: 1. Dorsal parietal cartilage. 2. Ventral parietal cartilage. 3. Alar cartilage (in horse). 4. Medial accessory nasal cartilage. 5. Lateral accessory nasal cartilage. 6. Nasal septum. Nasal cartilages: Medial accessory nasal cartilage: Inside the alar fold Originates from the ventral nasal concha and ventral lateral nasal cartilage. In horse, it forms a large S-shaped structure. In dog, it is smal. Septum nasi: Sagittal partition divides the nasal cavity into right and left halves. Medial support of the nose. Caudal part is osseous while the rostral part is cartilaginous. Nasal cartilages in horse: Alar cartilages (horse): comma shaped. support nostrils dorsally, medially and ventrally. Alar fold projects laterally into dorsal part of the nostril dividing it into: 1. false nostril dorsal and blind 2. true nostril ventral and opened leads into nasal cavity. Nasal cartilages in dog: 18  Alar fold in dog Alar fold is a rostral extension of ventral nasal conchae.  Nasal cartilages in dog: Alar fold is a rostral extension of ventral nasal conchae. The opening of the nasolacrimal duct is also located in the rostral aspect of the nasal cavity. 20 Muscles of the nose and upper lip : They help to dilate the nose. They are well developed in horse. They are poorly developed in dog.  Nasal cavity It is a hollow cylindrical passage extending behind the nostrils where airflow is directed to the caudal nares or choanae where it opens into the nasopharynx. It is lined with mucous membranes that further filter and humidify the air. Nasal septum is a thin cartilage and bone wall dividing the nasal cavity into left and right sides. Boundaries of the nasal cavity: Roof: frontal and nasal Floor: incisive and maxillary Lateral: maxilla and incisive bones Medial: nasal septum, vomer/ ethmoid Parts of the nasal cavity: 1. Nasal vestibule is the rostral part, lined by cutaneous mucous membrane. 2. Nasal cavity proper is the middle, largest part and is lined with respiratory mucous membrane. It contains turbinates: Bony structures covered in mucous membranes that protrude into the nasal cavity, increasing its surface area. They help to warm, humidify, and filter the air as it passes through nose. 3. Nasal fundus is the caudal part, lined by olfactory mucous membrane. Parts of the nasal cavity: Parts of the nasal cavity:  Nasal vestibule:  The nasal vestibule is the entrance area to the nasal cavity, regulating airway resistance and filtering incoming air. The vestibule conditions the air before reaching deeper nasal structures.  Nasal vestibules contain hair-like structures called cilia, which trap dust, pollen, and other particles from inhaled air and prevent them from entering respiratory system. Filtration protects the nasal passages and prevents harmful substances from reaching the lungs.  Nasal vestibule contains mucous glands that moisten and humidify the air, maintaining the optimal conditions for respiration within the nasal cavity. Nasal vestibule: The nasal vestibule contains three folds: 1. Straight fold is dorsal, joins dorsal concha. 2. Alar fold joins ventral nasal concha and contains medial accessory cartilage 3. Basal fold is the most ventral fold. In horse, it originates from ventral concha, while in other animals, it is independent of the concha and unites rostrally with the alar fold. The opening of nasolacrimal duct is located on the floor of the nasal vestibule at the junction of the skin and the mucous membrane. Nasal cavity proper:  Nasal cavity proper:  Contains nasal concha that project from lateral wall of nasal cavity.  Contains: 1. nasoincisor duct, 2. vomeronasal organ, 3. nasolacrimal duct 4. lateral nasal glands. Nasal cavity proper: 1. Dorsal nasal concha 2. Ventral nasal concha 3. Middle nasal concha (small, caudal) 4. Ethmoidal concha (small, caudal) 5. Dorsal nasal meatus 6. Middle nasal meatus (sinus meatus) 7. Ventral nasal (respiratory meatus) 8. Common nasal meatus Nasal fundus: Parts of the nasal fundus: 1. Olfactory part (dorsally) that contains lateral masses of ethmoid bone (ethmoidal conchae). 2. Nasopharyngeal opening (choanae) or posterior nares (ventrally). They are two elliptical orifices where nasal cavity and pharynx communicate. Olfactory Epithelium is a specialized tissue in the nasal fundus containing millions of olfactory receptor cells. The cells detect odor molecules and transmit signals to the brain, enabling the dog's sense of smell. The horses and mostly the dogs rely on their olfactory senses to interpret the world around them, and their nostrils are finely tuned to pick up the faintest of scents. Vomeronasal organ: The sense of smell is particularly mature partly due to the fact that horses have Jakobson's organ; an additional olfactory organ. With this organ, horses can even sniff out pheromones. For example, even the smallest smells can scare the horse. At the same time, however, it can also sense predators long in advance and get to safety. There are many olfactory nerves in the large nostrils, which enable horses to filter what they want to eat in the pasture and what not. With their nostrils, they roam over grasses and herbs and then use all this information to decide which ones they want to eat.  Vomeronasal organ (organs of Jacobson)  It is a pair of ducts lie in the floor of nasal cavity and contains elements of respiratory and olfactory regions.  They are 15-20 cm, in horse.  It extend caudally from their openings in the incisive duct at the level of canine tooth to a level of the 2nd to 4th cheek teeth, where they end blindly.  Incisive duct (nasopalatine duct)  It is a paired tube in the floor of nasal cavity, directed rostroventrally and connect the nasal cavity with the oral cavity (has two orifices (nasal and oral).  Its nasal opening is hidden in the ventral meatus at the level of canine tooth.  Its oral opening on the incisive papilla lie just caudal to the upper incisors. In horse, it is obliterated (blind).  Lateral nasal gland This gland lies close to the nasomaxillary aperture and runs along with the middle meatus and opens inside the nostril close to the straight fold at the level of first and second cheek tooth. The secretion to helps moisten the inhaled air. Paranasal sinuses 1. Maxillary sinus 2. Frontal sinus 3. Palatine sinus 4. Sphenoid sinus 5. Lacrimal sinus Paranasal sinuses:  They are irregular spaces, which excavate some bones of the skull.  Their lining mucous membrane is continuous with that of nasal cavity. Functions of paranasal sinuses: 1. They offer thermal and mechanical protection to the orbits, nasal and cranial cavities. 2. Enlarge the skull area for muscle attachment without increasing weight. 3. Affect the resonance of voice. Paranasal sinuses: animal Horse Dog sinus Maxillary + Recess Frontal + s Lacrimal - + Palatine - - Sphenoid - - Spheno- + - palatine + Present, - Absent Connection with the nasal cavity in horse  All paranasal sinuses communicate either directly or indirectly with the middle nasal meatus.  The rostral and caudal maxillary sinuses open directly into the nasal cavity.  The frontal and spheno-palatine sinuses open into the caudal maxillary sinus. Paranasal sinuses in dog:  Maxillary sinus is a recess and communicates through a large opening with middle nasal meatus.  Frontal and sphenoid sinuses are joined to the ethmoidal meatuses.  Palatine and sphenoid sinuses are absent.  Nasopharynx  The nasopharynx is the portion of the pharynx dorsal to the hard and soft palates.  The choanae are the rostral nasopharyngeal meatus; they are considered the caudal border of the nasal cavity.  At this location, the ventral, dorsal, and lateral walls of the nasopharynx are formed by the hard palate, vomer bone, and palatine bone, respectively.  Each auditory tube opens into the lateral nasopharynx through a slitlike opening directly caudal to the caudal border of the pterygoid bone. Nasal cavity in the dog: Midsagittal section of the nose of a dog showing the four conchae (dorsal, middle, ventral, and ethmoidal).  Assignment It has been found that A dog's sense of smell is said to be a thousand times more sensitive than that of humans. Dogs has more than 220 million olfactory receptors in its nose, while humans have only 5 million. Why Dogs Noses Are Wet? 45