The Head and Neck

1. The Head and Neck

2. Nose Nostril Nasal Cavity Oral Cavity Pharynx Upper Respiratory Tract pg 992

3. Nose is the only portion of the RT that is externally visible CT, bone, hyaline cartilage Air enters here during breathing Passes through the external nares (nostrils) Nose pg 1023

4. Superior to nostrils Skin lined with: Sebaceous glands Greasy secretion Collect dirt Lubricate Kill bacteria Sweat glands Acidic Slows growth of bacteria Hair follicles Trap small particles of dirt Vibrissae Nose hairs Filter large particles (insects) Vestibule pg 1013

5. Nasal Cavity • Functions: • Provides airway for respiration • Moistens and warms air • Filters inhaled air • Resonating chamber for speech • Houses olfactory receptors • 2 divisions: • External nose • Internal nasal cavity pg 1023

6. Divided into R and L by nasal septum Continuous with the nasopharynx through the internal nares (choanae) Nasal Cavity pg 992

7. Nasal Cavity • Boundries: • Roof – ethmoid bone (cribiform plate) • Floor – maxilla (palatine process) palatine (horizontal plate) • Lateral walls – nasal bones, superior and middle nasal conchae of ethmoid bone, inferior nasal conchae, maxilla, palatine bone • Hard palate • Palatine bones and maxillary bone • Soft palate • Skeletal muscle posterior portion • End in uvula

8. Respiratory Mucosa Pseudostratified ciliated columnar epithelium Goblet cells Lamina propria Mucous and serous cells Venous plexus Function is to filter and warm inhaled air Highly innervated Sneeze! Olfactory Mucosa Roof of nasal cavity Houses smell receptors No goblet cells Cilia modified for olfaction Lining of the Nasal Cavity www.mc.vanderbilt.edu/.../Respiratory03.htm

9. Nasal Conchae • Project medially from each lateral wall • 3 structures: • Superior of ethmoid bone • Middle of ethmoid bone • Inferior • Functions: • Create turbulence to increase: • Filters air • Heats air • Moistens air • Reclaim heat and moisture during exhalation pg 1023

10. Air filled cavities that surround the nasal cavity Lined by mucosa Perform same function as nasal cavity and lightens skull Located in Frontal, Ethmoid, Sphenoid, Maxilla bones Paranasal Sinuses pg 1018

11. Connects the nasal cavity and mouth to larynx and esophagus Extends from base of skull to level of C6 vertebra Common passage for food and air Lined with skeletal muscle Divided into: Nasopharynx Oropharynx Laryngopharynx Pharynx pg 992

12. Lymphoid organ MALT Swellings of the mucosa lining the pharynx Form ring around the entrance to the pharynx 4 groups: Palatine Lingual Pharyngeal Tubal Remove pathogens Tonsils pg 992

13. Location: Posterior to nasal cavity Inferior to sphenoid bone Superior to level of soft palate ONLY an air passageway Closed off during swallowing by the soft palates’ uvula Giggling! Ciliated pseudostratified epithelium Contain: Pharyngeal tonsils (adenoids) Tubal tonsils Nasopharynx pg 992

14. Location: Posterior to the oral cavity Extends inferiorly from level of the soft palate to level of the esophagus Swallowed food and inhaled air pass through here Stratified squamous epithelium Contain: Palatine tonsils Lingual tonsils Oropharynx pg 992

15. Location: Lies posterior to larynx Continuous with the esophagus and larynx Common passageway for food and air Food – esophagus Air - larynx Stratified squamous epithelium Laryngopharynx pg 992

16. “Voice box” Extends from C4 to C6 Attachments: Hyoid bone superiorly Continuous with trachea inferiorly Functions: Vocalization Provides open airway Switches to route air and food into proper channels Innervation: Vagus Superior part = stratified squamous epithelium Below vocal cords= ciliated pseudostratified columnar Larynx pg 1001

17. All hyaline cartilage except epiglottis Composed of 9 cartilages connected by membranes and ligaments: 1 Thyroid 1 Cricoid 1 Epiglottis 2 Arytenoid 2 Corniculate 2 Cuneiform Larynx pg 1001 pg 1000

18. Thyroid Cartilage Large Shield shaped Formed by 2 plates Contains laryngeal prominence Adam’s Apple!! Laryngeal Cartilages pg 998

19. Cricoid Inferior to thyroid cartilage Forms a complete ring Directly superior to trachea Laryngeal Cartilages pg 998

20. Epiglottis Composed of elastic cartilage Covered by mucosa Projects upward from anterior wall of laryngeal inlet to level of base of tongue Close off larynx during swallowing Laryngeal Cartilages pg 999

21. Located in the larynx Mucosal folds formed by vocal ligaments Composed of elastic fibers Run from arytenoid cartilages (posterior) to the thyroid cartilages (anterior) Exhaled air passes over them and causes vibration Force of air = volume Length & tension of folds = pitch False vocal cords Vestibular folds (superior to true) Vocal Cords pg 1008

22. Location: In anterior neck On trachea, inferior to larynx 2 lateral lobes Connected by the isthmus Butterfly shape Largest endocrine gland in body Produces Thyroid hormone (TH) Increases metabolic rate Calcitonin Depresses excess levels of Ca+ in blood Thyroid Gland pg 966

23. Internally, composed of follicles Follicular cells TH Parafollicular cells Calcitonin Blood supply Superior thyroid arteries Branches of external carotids Inferior thyroid arteries Branches of subclavians Thyroid Gland

24. Two pairs Located on the deep surface of the lateral lobes of the thyroid gland Produce parathyroid hormone Increases blood calcium levels Parathyroid Gland pg 966

25. Location: Inferior to mandible In anterior neck Associated with the skull Only bone in skeleton that does not articulate directly to another bone!!! Attaches via ligaments to temporal bone, larynx Composed of: Body 2 pairs of horns Functions: Moveable base for tongue Points of attachment for larynx and neck muscles Sternohyoid, thyrohyoid, Hyoid Bone pg 803

26. Mouth Tongue Teeth External Salivary glands Oral Cavity and Associated Organs pg 992

27. Food enters alimentary canal through here Mucosa-lined Thick stratified squamous epithelium, with keratinization in some areas Boundaries: Lips anteriorly Cheeks laterally Palate superiorly Tongue inferiorly Oropharynx posteriorly Mouth divided into 2 parts: Vestibule Oral cavity proper Mouth - Oral Cavity pg 1041

28. Mouth • Lips (labia) and Cheeks • Keep food inside mouth during chewing • Composed of skeletal muscle surrounded by skin • Lips formed by orbicularis oris muscle • Cheeks; Muscles of Mastication • Temporalis & Masseter (elevate mandible, close mouth) • Buccinator (chewing) • Digastric (lower mandible against resistance, opens mouth) • Pterygoids (lateral movements) • Palate: forms the roof of the mouth • Soft palate (posterior) rises to close off nasopharynx during swallowing; made of skeletal muscle • Hard palate (anterior) provides surface for tongue to force food against during chewing

29. Tongue • Functions • Grips and moves food between teeth during chewing • Mixes food with saliva = BOLUS • Moves bolus down pharynx • Speech production • Houses taste buds (= gustation) • Creates floor of mouth • Attachments: hyoid, mandible, styloid process, soft palate • Made of Skeletal muscle with a CT septum • Intrinsic muscles (change shape; rolling) • Extrinsic muscles (movement; protrude, retract) • Motor = Hypoglossal (CN XII) • Sensory = Mandibular (CN V3), Facial (CN VII), Glossopharyngeal (CN IX) pg 1037

30. Moving Bolus • Swallowing voluntarily initiated (pharynx) • Peristalsis = propulsion • Involuntary • Alternate waves of contraction and relaxation of muscles in organ walls (e.g. esophagus) • Squeezes food from one organ to next • Some mixing www.answers.com

31. Compound tubuloalveolar glands Intrinsic salivary glands In mucosa of tongue, palate, lips and cheeks Keeps mouth moist at all times Extrinsic salivary glands Lie external to mouth Connected by ducts Secrete only during eating or prior to (“mouth watering”) 3 paired glands: Parotid Submandibular sublingual pg 1043 Salivary Glands pg 863

32. Produce saliva Mixture of water, ions, mucus and enzymes Moistens mouth Dissolves food for taste Binds food into a bolus Enzymes digest starch Bicarbonate buffer neutralizes acids Kill microorganisms Contains proteins to promote growth of beneficial bacteria Salivary Glands pg 1046

33. Function: Ingestion and mechanical breakdown of food Have 2 sets of teeth (dentitions) Primary dentition / deciduous (milk) teeth Permanent dentition Incisors: rip, cut Canines: tear and pierce Premolars: grinding Molars: grinding Teeth – From Eruption to Edentate pg 1056

34. Gomphosis Synarthrosis Peg in socket with ligament The sockets (alveoli) are in gum-covered margins in mandible and maxilla Periodontal ligaments (collagen fibers) anchor tooth in bony socket Continous with gingiva (gum) Teeth

35. Enamel Made of calcium salts Avascular, acellular Not renewed or replaced HARDEST substance in body!!!! Dentin Underlines enamel Forms bulk of tooth Made of minerals and collagen Maintained during life Harder than bone Cementum Calcified external surface Attaches tooth to periodontal ligament Teeth Substances

36. Regions: Crown Covered with enamel Projecting into oral cavity Neck (gumline) Root Area beyond neck in alveolus Pulp cavity Center of tooth Loose CT with vessels and nerves Supplies nutrients to hard tissues Teeth

37. Root Canal Portion of the pulp cavity in the root Apical foramen Opening into the root canal at the tip of each root Blood supply Superior/Inferior Alveolar artery, branches of External Carotid artery Innervation Maxilla = Superior Alveolar Nerves Mandible = Inferior Alveolar Nerves Teeth

38. Number of erupted teeth = 0 Jaws covered by gingiva (gums) Lots of drooling!!! Teeth at Birth

39. Lower central incisors first to appear 8 Incisors = 6-10 months 4 Canines = 16-20 months 4 1st Molars = 12-16 months 4 2nd Molars = 20-24 months 20 deciduous teeth emerge by age 2 Dental formula Describes the number and position of classes of teeth (half of the mouth) 2I, 1C, 2M 2I, 1C, 2M First Teeth – 6 Months pg 1056 X 2 = 20 Deciduous teeth dental formula: ****No premolars!

40. Permanent teeth enlarge and develop Roots of deciduous teeth reabsorbed Teeth loosen and fall out Begin to erupt from 7-13 years of age Third molars (wisdom teeth) emerge from 17-25 years May be absent!! Adult dental formula: 2I, 1C, 2P, 3M 2I, 1C, 2P, 3M Adolescence – Adult X 2 = 32 pg 1056

41. Cavities (caries) Demineralization of enamel by bacteria In severe cases, erodes the dentin of tooth Most severe cases erosion penetrates pulp cavity Tooth Troubles

42. Gingivitis Inflammation of the gingiva caused by plaque accumulation Leads to……. Periodontitis Infection of periodontal ligament leading to its destruction along with the bone around the teeth Leads to toothlessness! Tooth Troubles

43. Triangles of the Neck • Neck subdivided into two triangles • Separated by the sternocleidomastoid muscle • Anterior triangle • Posterior triangle

44. Boundries: Anterior - sternocleidomastoid Posterior - trapezius Inferior – clavicle Contents: Nerves: accessory nerve, phrenic nerve, brachial plexus Artery: Subclavian Vein: External jugular Triangles of the Neck: Posterior pg 948

45. Boundries: Anterior - midline Posterior - sternocleidomastoid Superior – inferior margin of the mandible Contents: Glands: Submandibular Muscles: Suprahyoid and infrahyoid muscles Artery: Common carotid Vein: Internal jugular, External jugular Nerve: Accessory Triangles of the Neck: Anterior pg 954