Mouth, Throat, Abdomen and Rectum

• Structure and Function: Mouth and Throat - Comprise the first part of the digestive system and responsible for receiving food (ingestion), tasting, preparing food for digestion, and aiding in speech.
• An extension of the soft palate is the uvula, which hangs in the posterior midline of the oropharynx.
• The mouth is the beginning of the digestive tract and serves as an airway for the respiratory tract.
• The mandible (jaw bone) provides the structural support for the floor of the mouth.
• The roof of the oral cavity is formed by the anterior hard palate and the posterior soft palate.
• The gums (gingiva) are covered by mucous membrane and normally hold 32 permanent teeth in the adult.
• The top, visible, white enameled part of each tooth is the crown.
• The portion of the tooth that is embedded in the gums is the root.
• The crown and root are connected by the region of the tooth referred to as the neck.
• Small bumps called papillae cover the dorsal surface of the tongue. Taste buds, scattered over the tongue’s surface, carry sensory impulses to the brain.
• The three pairs of salivary glands secrete saliva (watery, serous fluid containing salts, mucus, and salivary amylase) into the mouth.
• Saliva helps break down food and lubricates it
• Amylase digests carbohydrates.
• The submandibular glands, located in the lower jaw, open under the tongue on either side of the frenulum through openings called Wharton ducts
• The roof of the oral cavity is formed by the anterior hard palate and the posterior soft palate.
• The tongue assists with moving food, swallowing, and speaking
• Parotid glands - located below and in front of the ears, empty through Stensen ducts, which are located inside the cheek across from the second upper molar.
• Throat (pharynx) - located behind the mouth and nose, serves as a muscular passage for food and air.
• Nasopharynx: Upper part of the throat
• Oropharynx: Below the nasopharynx
• Laryngopharynx: Below the oropharynx
• Palatine Tonsils - Masses of lymphoid tissue that are located on both sides of the oropharynx at the end of the soft palate between the anterior and posterior pillars.
• Lingual Tonsils - Lie a the base of the tongue.
• Tonsils help protect against infection since they are masses of lymphoid tissue.
• Lip cancer can occur anywhere but is most common on lower lip.
• Whitish, curd-like patches that scrape off over reddened mucosa and bleed easily indicate “thrush” (Candida albicans) infection.
• The side of the tongue is the most common site of tongue cancer.
• HERPES SIMPLEX TYPE I (COLD SORES): Clear vesicles surrounded by red indurated base

  
• CHEILOSIS OF LIPS: Scaling painful fissures at corner of lips

  
• CARCINOMA OF LIP: Round, indurated lesion becomes crusted and ulcerated with elevated border

  
• LEUKOPLAKIA (VENTRAL SURFACE): Thick raised patch does not scrape off; seen in heavy tobacco or alcohol use

  
• HAIRY LEUKOPLAKIA (LATERAL SURFACE)

  
• CANDIDA ALBICANS INFECTION (THRUSH): Curd-like patches easily scrape off, leaving a reddened area

  
• SMOOTH, REDDISH, SHINY TONGUE WITHOUT PAPILLAE DUE TO VITAMIN B12 DEFICIENCY

  
• BLACK HAIRY TONGUE: Not hair, but elongated filiform papillae seen with use of antibiotics that inhibit normal bacteria

  
• CARCINOMA OF TONGUE: Round indurated lesion becomes crusty and ulcerated with elevated border

  
• CANKER SORE: Painful small ulcers inside mouth; do not occur on lip surface; noncontagious

  
• GINGIVITIS: Red swollen gums that easily bleed

  
• RECEDING GUMS: Gum tissue surrounding tooth pulls back, exposing more of tooth or root of tooth
• KAPOSI SARCOMA LESIONS: Advanced lesions seen in HIV