Gross Anatomy Digestive System Generalities PDF

GROSS ANATOMY Digestive System Generalities by Dr. Esguerra Nov. 14, 2013 ORAL CAVITY DIVISIONS OF THE ORAL CAVITY  Oral (Postsulcus) &...

GROSS ANATOMY Digestive System Generalities by Dr. Esguerra Nov. 14, 2013 ORAL CAVITY DIVISIONS OF THE ORAL CAVITY  Oral (Postsulcus) & Pharyngeal (Presulcus) parts 1. ORAL VESTIBULE  A mobile, strong, muscular, organ  It is connected exteriorly by a fissure in the lip  Can assume a variety of shapes and positions  Posteriorly connected to the oral cavity proper through a  Partly in the oral cavity proper and partly in the slit in the 2nd molar, bilaterally of the jaw and the mandible pharyngeal area 2. ORAL CAVITY PROPER  Mainly composed of muscles and covered by mucous  Roof = composed of hard and soft palate membrane  Floor = mainly of the tongue, connected midline via the  Assists with: frenulum o Mastication = pushes the food against the teeth which initiates chewing o Taste = due to the presence of taste buds o Deglutition = pushes the food backward towards the esophagus o Articulation = because it assumes variety of shapes and position o Oral cleansing MUSCLES OF THE TONGUE 1. INTRINSIC MUSCLES  Action: Alter the shape of the tongue (only action). TEETH  Confined to the tongue and are not attached to bone 1. DECIDUOUS TEETH (milk teeth)  Consist of longitudinal, transverse, and vertical fibers  Four molars, four incisors, two canines per jaw = 20 2. EXTRINSIC MUSCLES  Erupt about 6 months after birth and have all erupted by  Attached to bones and soft palate the end of 2 years, BUT NOT ALWAYS.  Teeth of the lower jaw usually appear before those of the upper jaw 2. PERMANENT TEETH  Four incisors, two canines, four premolars, and six molars in each jaw = 32  Begin to erupt at 6 years of age  Last tooth to erupt is the third molar (wisdom tooth), which may happen between the ages of 17 and 30 SENSORY INNERVATION  Mainly innervated by the Trigeminal Nerve  Maxillary Nerve of the Trigeminal Nerve (V2) o Supplies the upper jaw o Traverses the mandible then gives off nervous plexuses that supply the teeth of the upper jaw  Mandibular Nerve of the Trigeminal Nerve (V3) o Traverses the mandible then gives off nervous plexuses that supply the teeth of the lower jaw TONGUE Page 1 of 7 TRANSCRIBED BY: Olive :D  MOVEMENTS OF THE TONGUE SALIVARY GLANDS  Protrusion: Genioglossus muscles on both sides acting Parotid Sub- Sublingual together Mandibular  Retraction: Styloglossus and hyoglossus muscles on both Location Below the Beneath the Beneath the sides acting together external lower body of mucus  Depression: Hyoglossus muscles on both sides acting meatus the body of the membrane together mandible (sublingual  Retraction and elevation of the posterior third: Behind the fold) of the Styloglossus and palatoglossus muscles on both sides ramus of Divided into floor of the acting together the superficial and mouth mandible upper part by  Shape changes: Intrinsic muscles the mylohyoid Close to the  In front of muscle frenulum of the SENSORY INNERVATION the SCM tongue ANTERIOR 2/3 Deep part lies  Traverses the styloglossus beneath the  General sensation: Lingual nerve branch of mandibular mucuous division of trigeminal nerve membrane on  Taste sensation: Chorda tympani branch of the facial the side of the nerve tongue POSTERIOR 1/3 Ducts Stensen’s Wharton’s duct Bartholin’s duct  Traverses the stylopharyngeus and pierces the thyrohyoid duct (largest) membrane Rivinus duct  General and taste sensation: Glossopharyngeal nerve (minor) Termination Small Small papilla Summit of the *general sensation = temperature (warm, cold), pain of duct papilla situated at the sublingual fold opposite side of the the upper frenulum of the second tongue molar tooth Type of Alpha- Amylase Mucin; purely secretion amylase Mucin saliva Motor Glosso- Facial nerve Facial nerve Innervation pharyngea via the chorda via the chorda l nerve tympani; tympani; submandibular submandibular ganglion BLOOD SUPPLY  Lingual Artery o Main supplier o Tributary of the external carotid artery  Tonsillar branch of the facial artery  Ascending pharyngeal artery  Veins drain into the internal jugular vein o Single drainage system LYMPHATIC DRAINAGE Part of the Tongue Lymph Nodes Tip Submental lymph nodes Sides of the anterior two Submandibular and deep thirds cervical lymph nodes Posterior third Deep cervical lymph nodes *Tongue Cancer = removes all lymph node to prevent metastasis Page 2 of 7 TRANSCRIBED BY: Olive :D  NASOPHARYNX  Lies above the soft palate  Lies behind the nasal cavities  Begins at the choanae and ends at the level of lower/posterior border of soft palate  Always patent  Rigid walls (except anterior)  Function: purely respiratory  Auditory tube/ Eustachian tube opening found here PAROTITIS  Pharyngeal Recess (Fossa of Rosenmuller) - a  Inflammation of the parotid gland depression in the pharyngeal wall behind the tubal  Caused by either a bacteria, virus or direct trauma to the elevation gland  Salpingopharyngeal fold- vertical fold of mucous  Painful because it is enclosed in a fibrous capsule (fascia) membrane covering the salpingopharyngeus muscle which is usually surgically cut to relieve pain.  Torus Tubarius (tubal elevation) – elevations above and  During parotidectomy, look for the facial nerve as a behind the opening of the eustachean tube due to the landmark. It divides the gland into its superficial and deep presence of tubal tonsil beneath the mucosa part.  Pharyngeal Isthmus – slight constriction between  Behind the facial nerve is the deep lobe of the parotid oropharynx and nasopharynx; opening in the floor gland. between the soft palate and the posterior pharyngeal wall  Facial nerve has 5 branches. OROPHARYNX  Lies behind the oral cavity  floor is formed by the posterior one third of the tongue and the interval between the tongue and epiglottis  Extends from the posterior/lower border of the soft palate to the upper border of the epiglottis  Anterior limit is the palatoglossal fold/arch and the pharyngeal aspect of the tongue  Posterior limit – palatopharyngeal fold  lateral wall consists of the palatopharyngeal fold/arch and palatine tonsil  vertebral level is C2 and upper border of C3 vertebra  tonsillar fossa or sinus is the space between the palatoglossal arch and palatopharyngeal arch which contains the palatine tonsil PHARYNX  Function: Respiratory and digestive  Situated behind the nasal cavities, mouth and larynx  A musculomembranous tube (12-14 cm long)  Funnel shaped  Extends from the cranial base (upper, wider end) above the level of C6 vertebra and lower border of cricoid below (lower, narrow end)  It has 3 parts:  Nasopharynx (Nasal part)  Oropharynx (Oral part)  Laryngopharynx (Laryngeal part)  Contents: o median glossoepiglottic fold o lateral glossoepiglottic fold o vallecula found in between the posterior 3rd of tongue and epiglottis which harbors the swallowed foreign bodies o The valleculae are depressions formed between a midline mucosal fold and two lateral folds that connect the tongue to the epiglottis Page 3 of 7 TRANSCRIBED BY: Olive :D  LARYNGOPHARYNX LINGUAL TONSILS  extends from the superior border of the epiglottis to the  on the posterior one-third of the tongue inferior border of the cricoid cartilage  lateral wall is formed by the thyroid cartilage and the thyrohyoid membrane  Largest area  piriform fossa is a depression in the mucous membrane on each side of the laryngeal inlet; pushes out foreign bodies TUBAL TONSIL  collection of lymphoid tissue in the submucosa of the pharynx near the pharyngeal orifice of the pharyngotympanic tube  Pharyngoesophagus – tonically contracted because of cricopharyngeus muscle which is a part of the lower fibers of inferior pharyngeal fibers PHARYNGEAL MUSCLES  Cricopharygeus muscle guards the superior opening of esophagus LYMPHOID ORGAN/ TONSILS Tonsillar ring of Waldeyer or Circumpharyngeal Lymphoid RIng  A protective annulus ring consisting of the pharyngeal, palatine, tubal and lingual tonsils that encircle the entrance of the pharynx  lateral part: formed by the palatine tonsils and tubal tonsils (lymphoid tissue around the opening of the auditory tube in the lateral wall of the nasopharynx)  upper part: pharyngeal tonsil in the roof of the nasopharynx  lower part: lingual tonsil on the posterior third of the tongue  Tonsils belong to the category of mucosa-associated lymphoid tissue (MALT) PHARYNGEAL TONSIL  Collection of lymphoid tissue in the submucosa of the roof of the nasopharynx  ascending pharyngeal and ascending palatine arteries  tonsillar branches of the facial artery  pharyngeal branch of the maxillary artery  artery of the pterygoid canal  forms part of the circumpharyngeal lymphoid ring (Waldeyer's ring)  presumably contributes to the defense of the upper respiratory tract  Numerous communicating veins  internal submucous and external pharyngeal venous plexuses PALATINE TONSILS  two masses of lymphoid tissue  located in the depression on the lateral wall of the oropharynx between the palatoglossal and palatopharyngeal arches  Surface is pitted by numerous small openings that lead into the tonsillar crypts; it is usually seen by paediatricians to inspect for inflammation  The tonsil is covered on its lateral surface by a fibrous capsule  Veinous drainage is to the external palatine, the pharyngeal, or the facial veins  Lymphatic drainage in the upper deep cervical lymph nodes Page 4 of 7 TRANSCRIBED BY: Olive :D  Page 5 of 7 TRANSCRIBED BY: Olive :D  Things emphasized by Dr. Esguerra in the lecture:  All pharyngeal muscles are innervated by the pharyngeal plexus except for stylopharyngeus which is innervated by the glossopharyngeal nerve (cricopharyngeus was left blank in the table).  The three constrictor muscles (superior, middle, inferior) are mainly responsible for moving the bolus downward from pharynx to esophagus  Cricopharyngeus muscle takes part in the sphincter mechanism. Helps the sphincter close and open.  Stylopharyngeus works during swallowing. INNERVATION  Nasal pharynx: innervated by the maxillary nerve which is the 2nd branch of the trigeminal nerve  Oral pharynx: The glossopharyngeal nerve  Left side: The left subclavian artery, the aortic arch, the  Laryngeal pharynx (around the entrance into the larynx): thoracic duct, and the mediastinal pleura The internal laryngeal branch of the vagus nerve INNERVATION AND LYMPH DRAINAGE  Blood supply: o Ascending pharyngeal artery o tonsillar branches of facial arteries o branches of maxillary and lingual arteries  Lymph Drainage o Directly into the deep cervical lymph nodes or indirectly via the retropharyngeal or paratracheal nodes into the deep cervical nodes ESOPHAGUS  Muscular tube about 10 in. (25 cm) long, extending from the pharynx to the stomach  Begins at the level of the cricoid cartilage (which is the termination of the laryngopharynx), opposite the body of the sixth cervical vertebra.  It commences in the midline, but as it descends through the PHYSIOLOGIC CONSTRICTIONS neck, it inclines to the left side 1. Cervical Constriction- Where the pharynx joins the RELATIONS upper end of the esophagus (C6) 1. Neck/ Cervical Part 2. Bronchoaortic Constriction- Where the aortic arch  The esophagus lies in front of the vertebral column and the left bronchus cross its anterior surface (T4)  Laterally, it is related to the lobes of the thyroid gland 3. Diaphragmatic Constriction- Where the esophagus  Anteriorly, it is in contact with the trachea and the recurrent passes through the diaphragm into the stomach (T10) laryngeal nerves Significance: These constrictions are areas where esophageal cancer  During thyroidectomy, one should be careful not to is most likely to occur because they are more prone to mechanical puncture the esophagus. Also be careful not to cut the stress due to hard foods and to carcinogenic foods. Pag nagagasgas recurrent laryngeal nerve (sing-nipis daw ng buhok) which palagi, may pagpapalit ng cell na nagaganap na eventually may lead traverses the tracheoesophageal groove. If the cut is to cancer. Also when there are obstructions, dito pwede bumara yung unilateral, patient would have a husky voice. If bilateral, food or other stuff. patient would be unable to breathe. 2. In the Thorax  Anteriorly: The trachea and the left recurrent laryngeal nerve; the left principal bronchus, which constricts it; and NEUROVASCULAR STATUS the pericardium, which separates the esophagus from the Blood Supply Venous Lymphatic left atrium Drainage Drainage UPPER Inferior Thyroid Inferior Deep Cervical  Posteriorly: The bodies of the thoracic vertebrae; the RD 3 Artery Thyroid Veins Nodes thoracic duct; the azygos veins; the right posterior MIDDLE Esophageal Azygos veins Superior and intercostal arteries; and, at its lower end, the descending RD 3 Branches of Posterior thoracic aorta the descending Mediastinal Thoracic aorta Nodes LOWER Branches of Left Gastric nodes along RD 3 the Left gastric Vein the left gastric Artery blood vessels and the celiac nodes NERVE SUPPLY  parasympathetic and sympathetic efferent and afferent fibers via the vagi and sympathetic trunks  In the lower part of its thoracic course, the esophagus is surrounded by the esophageal nerve plexus o **Majority vagus lang yan according kay sir  Right side: The mediastinal pleura and the terminal part of the azygos vein Page 6 of 7 TRANSCRIBED BY: Olive :D  FOOD BOLUS TRANSPORT 3 stages of swallowing: 1. Buccal Phase- voluntary  Bolus is pushed into the oropharynx 2. Pharyngeal Phase- involuntary  Bolus is pushed from pharynx to esophagus  Uvula blocks entrance to the nasopharynx  Epiglottis seals off the larynx to prevent food from entering the windpipe. 3. Esophageal Phase-involuntary  once it enters the upper esophageal sphincter DYSPHAGIA- difficulty in swallowing; most common pathologic problem of the esophagus. Either a problem in the sphincter mechanism or muscular action. ODYNOPHAGIA- painful swallowing \ Page 7 of 7 TRANSCRIBED BY: Olive :D