Anatomy #1; Respiratory Nose and the Nasal Cavity December 1st, 2013 Note #1: the doctor skipped some slides in the lecture. Those slides are not included in this sheet and so you will have to review the slides to study them. The reason they were not included is because well, the doctor probably skipped them for a reason. Note #2: I suggest you overview the whole sheet before "memorizing" any of it. After you gain an understanding of the general picture, it will be much easier to grasp. I. Functions of the respiratory system II. External nose i. Cartilaginous part ii. Bony framework iii. Blood supply iv. Nerve supply III. Nasal cavity i. Functions ii. Content iii. Boundaries iv. Mucosa v. Entries of paranasal sinuses vi. Blood supply vii. Nerve supply IV. Paranasal sinuses i. Functions ii. Frontal sinus iii. Ethmoidal sinus iv. Sphenoidal sinus v. Maxillary sinus 1 Anatomy #1; Respiratory Nose and the Nasal Cavity December 1st, 2013 I. Functions of the respiratory system: 1. Provides for gas exchange 2. Regulates blood ph: we notice that when they measure gas content of the blood with respiratory patients to make sure the ph is normal 3. Filters the inspired air 4. Contains receptors for smell, and produce vocal sounds (phonation): bipolar cells at the roof of the nasal cavity, olfactory nerve and bulb. Also, don't forget that vocal cords are in the larynx, we call them true vocal cords, responsible for production of sound. 5. Excretes small amounts of water and heat: large amount of seromucuous glands in submucosa to moisture and warm entering air Nose is made up of the nasal cavity, and the external nose. II. External Nose: i. Cartilaginous part: 1. Septal cartilage: anterior third of the septum 2. Lateral nasal cartilage: lower and upper lateral nasal cartilages 3. Alar cartilage: the moving parts of the cartilage, contains two muscles, constrictor naris and dilator naris Notes: The Dilator Naris and Contrisctor Naris allow some people to move their ala like rabbits. The ala is also moved in children who have a respiratory tract disease, when they inhale deeply. All these plates of cartilage are hyaline cartilage. ii. Bony framework: 1. The nasal bones: right and left nasal bones with a suture in between 2. Frontal processes of the maxillae 3. Nasal part of the frontal bone (this is the most medial part of the maxillary process of the frontal bone) iii. Blood supply: 1. Ophthalmic artery: arises from the internal carotid artery and enters the orbital vacity with the optic nerve 2. Maxillary artery: when we talk about the upper jaw and the nasal cavity, most of the arteries and nerves arise from the maxillary artery and nerve. In contrast to the lower jaw, where they usually arise from the mandibular. 3. Facial artery supplies the ala and the lower part of the septum 2 Anatomy #1; Respiratory Nose and the Nasal Cavity December 1st, 2013 iv. Nerve supply: 1. Infratrochlear nerve and External Nasal nerve, branches of the ophthalmic which is a branch of the trigeminal nerve 2. Infraorbital nerve, branch of the maxillary nerve Note that the external nose has blood supply and nerve supply through the ophthalmic and maxillary arteries and nerves. III. Nasal cavity: i. Functions: 1. Respiratory: through the alveoli 2. Olfactory: smell sensation through the olfactory nerve 3. Resonance of voice: through paranasal sinuses which open into the lateral wall of the nasal cavity 4. Drains lacrimal fluid: tears flow from lacrimal gland on the lateral side of the roof of the orbital cavity, some of them flow down over the cheek, while most of them go to the medial side of the orbital cavity to the lacrimal sack in the lacrimal fossa, where they drain through the nasolacrimal duct, which opens at the inferior meatus of the lateral wall of the nasal cavity. This is why when someone cries, they have a running nose. 5. Protective : Sneezing: expels foreign bodies Filtration: through the hair in the vestibule Proteolytic Enzymes: dissolve viruses and bacteria Warming and moistening the air: this is protective to brain cells ii. Content: Here we have a mid-sagittal section (slide #8), note: 1. Vestibule: first part of the nose after the anterior nares, has a stratified squamous keratinized epithelium, with characteristic thick and short hair called vibrissae 2. Anterior Nares (or External Nares): the anterior opening of the nasal cavity. They are always open, helped by the ala of the nose, which has constrictor naris and dilator naris(which widens the nares) 3. Choana (Posterior Nares or Interior Nares): connects the nasal cavity to the nasopharynx. They are surrounded by bone, we have to know the bones that form the boundaries of the choanae. Inferiorly: Horizontal plate of palatine bone Septum: Horizontal plate of palatine bone + vomer Laterally: Medial pterygoid plate of sphenoid Superiorly: Ala of vomer + sphenoidal process of palatine bone + vaginal process of medial pterygoid plate of sphenoid, and an important foramen called the palatovaginal canal 3 Anatomy #1; Respiratory Nose and the Nasal Cavity December 1st, 2013 iii. Boundaries: When we talk about the nasal cavity, we divide it into lateral wall (the part we can hold between our fingers), medial wall (the septum), floor and roof. Floor: Made up of the hard palate (you can touch it with your fingers at the roof of your oral cavity), which consists of two parts: 1. Palatine process of the maxillary bone forming the anterior part 2. Horizontal plate of the palatine bone forming the posterior part Roof: Made up of three parts: 1. Sloping anterior part: the nasal bones 2. Horizontal middle part: cribriform plateof the ethmoid bone, which is perforated to allow the passage of the filaments of the olfactory nerve 3. Sloping posterior part: sphenoid body + ala of the vomer + vaginal process of palatine bone Septum, or Medial Wall: 1. Anteriorly: septal nasal cartilage 2. Posteriorly: vomer inferiorly + perpendicular plate of ethmoid superiorly Note: The ethmoid bone participates in the roof giving cribriform plate, and also in the septum giving perpendicular plate of ethmoid In the lab we'll be able to see the vomer and perpendicular plate of ethmoid, but not the cartilage Lateral wall: you have to link the lateral wall with 3 conchae, 3 meatuses and 1 recess: the superior, middle and inferior conchae and meatuses (the meatuses lie below the conchae), and the sphenoethmoidal recess. Supporting bones for the lateral wall: 1. Perpendicular plate of palatine bone 2. Lacrimal bone 3. Frontal process of maxilla 4. The inferior concha is a separate bone 5. The middle and superior conchae are parts of the ethmoidal bone Parts of the lateral wall: 1. Vestibule: first part of the nose after the anterior nares, has a stratified squamous keratinized epithelium, with characteristic thick and short hair called vibrissae 4 Anatomy #1; Respiratory Nose and the Nasal Cavity December 1st, 2013 2. Antrum (or Atrium): is a space on the level of the middle meatus but lying anteriorly above the vestibule 3. The 3 conchae meatuses (superior, middle and inferior), and 1 recess (sphenoethmoidal recess) iv. Mucosa: The mucosa of the nasal cavity is lined with respiratory mucous membrane, which is pseudo stratified ciliated columnar, except at two places: 1. Vestibule: lined with stratified squamous keratinized epithelium (which has characteristic thick and short hair called vibrissae, this is very similar to the skin) 2. Roof of the nasal cavity, which has the olfactory region, which in addition to the respiratory mucous membrane, has specialized cells responsible for smell sensation called bipolar cells Functions of the mucous membrane: 1. It has a large plexus of veins which helps warm the inspired air, which protects the brain cells: that's why if you go out late in the winter, you drink water to bring down the temperature, because if the air is too cold and warming doesn't happen correctly the brain cells can be affected causing some disease 2. Trapping of foreign particles and organisms v. Entries of the paranasal sinuses: Chonchae, meatuses, and the recess: A choncha is a process of bone covered by mucosa, with a groove below it called a meatus. It serves to increase the surface area, and divide the inspired air into smaller currents in order to moisture and warm it, which is one of the functions of the nose. The paranasal sinuses open into the lateral wall of the nasal cavity, it is important to know where exactly: 1. The sphenoidal air sinus opens into the sphenoethmoidal recess 2. The posterior ethmoidal sinus opens into the superior meatus 3. The nasolacrimal duct opens into the inferior meatus 4. The middle ethmoidal sinus, the anterior ethmoidal sinus, and the maxillary sinus open into the middle meatus according to the following details. The middle meatus has: 1. A bulge of mucosa, called the bulla ethmoidalis, where the middle ethmoidal sinus opens 2. A groove, or a gutter, below the bulla ethmoidalis, called the hiatus semilunaris, where the maxillary sinus opens posteriorly, and the anterior ethmoidal sinus opens anteriorly 5. The frontal air sinus opens through the frontonasal duct anterior to the middle meatus in an area called the infundibulum. Some books say the frontal sinus opens into the 5 Anatomy #1; Respiratory Nose and the Nasal Cavity December 1st, 2013 anterior part of the hiatus semilunaris, and other say it opens through the frontonasal duct into the infundibulum. Again: 1. Sphenoidal sinus: sphenoethmoidal recess 2. Maxillary sinus: posterior part of the hiatus semilunaris of the middle meatus 3. Frontal sinus: frontonasal duct into the infundibulum, which lies anterior to the middle meatus 4.