Mouth, Throat, Abdomen, and Rectum

• Mouth and throat


  • Comprise the first part of the digestive system
  • Functions: Receiving food, tasting and preparing food for digestion, aiding in speech
• Cranial nerves related to the mouth and throat

  • V (trigeminal)
  • VII (facial)
  • IX (glossopharyngeal)
  • XII (hypoglossal)
• Mouth (oral cavity)


  First part of the digestive system that is formed by the lips, cheeks, hard and soft palates, uvula, and the tongue and its muscles. It serves as an airway for the respiratory tract
• Soft palate


  Separates the oral cavity from the nasal cavity, prevents food from passing into the nasal cavity during chewing and swallowing
• Lips


  • Form the entrance to the mouth, serve as a protective gateway to the digestive and respiratory tract
• Cheeks


  • Form the lateral walls of the mouth, located within buccinator muscles which flatten cheeks against teeth.
• Tongue


  • Form the floor of the mouth, mass of muscle attached to the hyoid bone and styloid process.
• Uvula


  • Extension of the soft palate, hangs in the posterior midline of the oropharynx
• Mandible (jawbone)


  • Provides the structural support for the floor of the mouth
• Gums (gingiva)


  • Covered by mucous membrane, normally holds 32 teeth in adults and 20 for babies
• Teeth

  Adults have 32 teeth, babies have 20, consist of crown, root, and neck

  
• Salivary glands


  • Produce saliva, a watery, serous fluid containing salts, mucus, and salivary amylase which helps break down food and lubricates it, include parotid, submandibular, and sublingual glands
• Throat (pharynx)


  Located behind the mouth and nose, serves as passageway for food and air, includes nasopharynx, oropharynx, and laryngopharynx
• Tonsils


  • Lymph nodes in the back of the mouth and top of the throat that help protect against infection.
• Four quadrants of the Abdomen

  • Right upper quadrant (RUQ)
  • Right lower quadrant (RLQ)
  • Left upper quadrant (LUQ)
  • Left lower quadrant (LLQ)
• Three parts of the abdominal regions

  • Epigastric
  • Umbilical
  • Hypogastric/suprapubic
• Abdominal wall muscles


  • Outermost layer: external abdominal oblique
  • Middle layer: internal abdominal oblique
  • Innermost layer: transverse abdominis
  • Protect the internal organs in the abdominal wall and allow normal compression during functional activities
• Peritoneum

  • Parietal peritoneum: thin, shiny serous membrane that lines the abdominal cavity
  • Visceral peritoneum: provides a protective covering for most of the internal abdominal organs
• Abdominal viscera

  • Solid viscera: Liver, pancreas, spleen, adrenal glands, kidneys, ovaries, uterus
  • Hollow viscera: Stomach, gallbladder, small intestine, colon, bladder
• Solid viscera


  Organs that do not change shape depending on their contents
• Liver


  • Largest solid organ in the body
  • Located below the diaphragm in the RUQ of the abdomen
  • Composed of four lobes that fill most of the RUQ and extend to the left midclavicular line (LMCL)
• Pancreas


  • Located mostly behind the stomach, deep in the upper abdomen
  • Not palpable
  • Long gland extending across the abdomen from the RUQ to the LUQ
  • Functions as an endocrine gland and accessory organ of digestion
• Spleen


  • Approximately 7cm wide
  • Located above the kidney just below the diaphragm at the level of the 9th, 10th, and 11th ribs
  • Posterior to the left midaxillary line (LMAL) and posterior and lateral to the stomach
  • Normally not palpable
  • Functions to filter the blood of cellular debris, digest microorganisms, and return the breakdown of products to the liver
• Kidneys


  • Located high and deep under the diaphragm
  • Considered posterior organs and approximate with the level of T12 to L3 vertebrae
  • Kidney tenderness is best assessed at the costovertebral angle
  • Functions include filtration and elimination of metabolic waste products, play a role in blood pressure control and maintenance of water, salt, and electrolyte balances, and function as an endocrine gland by secreting hormones
• Ovaries


  • Located in the RLQ and LLQ
  • Normally palpated through bimanual examination of the internal genitalia
• Hollow viscera


  Organs that change shape depending on their contents
• Hollow viscera


  • Stomach
  • Gallbladder
  • Small intestine
  • Colon (large intestine)
  • Urinary bladder
• Stomach


  • Where the abdominal cavity begins
  • Distensible, flask-like organ located in the LUQ below the diaphragm and between the liver and spleen
  • Not palpable
  • Functions to store, churn, and digest food
• Gallbladder


  • Approximately 10cm long
  • Located near the posterior surface of the liver lateral to the MCL
  • Usually not palpated
  • Function is to concentrate and store the bile needed to digest fat
• Small intestine


  • Longest portion of the digestive tract
  • Approximately 7m long
  • Approximately 2.5cm in diameter
  • Normally not palpated
  • Functions include digestion and absorption of nutrients
• Colon (large intestine)


  • Approximately 1.4m long
  • Approximately 6cm in diameter
  • Originates in the RLQ, where it attaches to the small intestine at the ileocecal valve
  • Composed of three sections: ascending colon, transverse colon, and descending colon
  • Functions include secreting large amounts of alkaline mucus to lubricate the intestine and neutralize acids formed by the intestinal bacteria, and where water is absorbed, leaving waste products to be eliminated in stool
• Urinary bladder


  • Distensible muscular sac located behind the pubic bone in the midline of the abdomen
  • Function is to serve as a temporary receptacle for urine
• Anal canal


  • Final segment of the digestive system
  • Begins at the anal sphincter and ends ay anorectal junction
  • Lined with skin with no hair or sebaceous glands, but has many somatic sensory nerves, making it susceptible to painful stimuli
• Anal opening / anal verge


  • Has hairless, moist appearance
  • Extends interiorly, overlying the anal sphincter
• Anorectal junction


  • Above the internal sphincter
  • Dividing point of the anal canal and rectum
  • Not palpable but may be visualized during internal examination
• Rectum


  • Lowest portion of the large intestine
• Black stool indicates upper gastrointestinal bleeding
• Red blood in stool can be found with hemorrhoids, polyps, cancer, or colitis
• Clay-colored (gray/tan) stools result from a lack of bile pigment
• Yellow stool indicates steatorrhea.