Diseases of the Digestive System

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Diseases of the Digestive System

• Chapter 10

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Oral cavity
Mouth
Tongue
Pharynx
Salivaryglands
Esophagus
Liver
Stomach
Pyloricsphincter
Stomach
Gall-bladder
Smallintestine
Pancreas
Smallintestine
Largeintestine
Rectum
Figure 21.4
Anus
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Human Digestion (oral cavity)

• Chemical Digestion (saliva) - glycoproteins
  protect lining of esophagus
• Lubricates solid food
• Buffers in saliva neutralizes food (sodas)
• Antibacterial agents
• Amylase hydrolyzes starch

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Human Digestion (oral cavity)
TEETH
Incisors
Canine
Premolars
Molars
Wisdomtooth
Tongue
Salivaryglands
Opening of asalivary gland duct
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Human Digestion (oral cavity)

• Mechanical Digestion (chew)
• Incisors biting
• Canine tearing (bladelike)
• Premolars/molars crush/grind
• Tongue moves bolus to back of oral cavity

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Human Digestion ( oral cavity)

• Pharynx entry of gases and food
• When breathing, epiglottis is up an esophageal
  sphincter is contracted. Air moves into the
  larynx (voice box) which is attached to trachea
  (windpipe).
• When eating, epiglottis is down and and
  esophageal sphincter is relaxed.
• Esophagus larynx attached to pharynx.

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Diseases of the Mouth

• Caused by Bacteria, Viruses, or Fungi
• Stomatitis inflammation of oral tissue
• Viruses
• Herpes Simplex 1 or 2- ruptured ulcers in the
  mouth or outer lip
• Fungi
• Thrush/commonly found in infants of nursing
  mothers (Candida albicans)

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Diseases of the Mouth

• Bacteria
• Gonorrhea painful ulcerations in the mouth and
  throat
• Syphilis causes chanceres or ulcers
• Both can be cured by antibiotics
• Cancer of the Mouth
• Among the 10 leading causes of death
• Caused by alcohol tobacco

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Human Digestion (oral cavity)

• Esophagus moves food from pharynx to stomach
• 2 layers of muscle
• Circular muscle layer constricts esophagus
• Longitudinal muscle layer shorten esophagus
• Both circular/longitudinal layers creates a
  wavelike motion called peristalsis

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Diseases of the Esophagus

• Dysphagia difficulty in swallowing
• Esophageal Varices varicose veins in the
  esophagus that causes veins to appear very
  dilated and knotty
• Hiatal Hernia
• Protrusion of a part of an organ through a
  muscular wall.
• Protrusion of the stomach through the diaphragm

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Diseases of the Esophagus

• Esophagitis- inflammation of the esophagus
• Burning, chest pain
• Reflux backflow of acid contents of stomach
• Gastroesophageal Reflux Disease caused by
  incompetent cardiac sphincter

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Stomach

• Holds up to 2 liters of food and water
• Gastric Glands
• mucous cells secretes mucus and protects lining
  of stomach
• cells in stomach replaced every 3 days
• chief cells secrete pepsinogen

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Ulcers
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Stomach

• The gastric glands are located within the
  epithelial cells that lines the stomach
• Pits are located within stomach lining to allow
  entry of gastric juices into stomach
• Secretion of gastric juices are regulated by
  nerve signals hormones
• Stress may cause elevated hormone levels leading
  to ulcers

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Stomach

• 2 to 6 hours to empty after a meal
• Acid chyme food and gastric juices
• Pyloric sphincter separates stomach from small
  intestine
• Gastric ulcers open sores in stomach lining
  caused by Helicobacter pylori able to neutralize
  acid surrounding bacteria loss of mucus
  resulting in bacterial infection leading to
  gastritis (eliminated by antibiotics/bismuth)

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Diseases of the Stomach

• Gastritis- inflammation of the stomach
• Caused by irritants such as tobacco, alcohol,
  aspirin or infection
• Peptic Ulcers
• Lesions of body surfaces
• Ulcers of the stomach are called gastric ulcers
• May cause hemorrhage which may lead to blood in
  stool (H. pylori)

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ULCERS
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Stomach

• Gastroenteritis is an inflammation of the
  stomach and intestines
• Food contaminated with hyman or animal feces may
  carry microorganisms that cause gastroenteritis
  and food poisoning.
• Food poison is often caused by Salmonella and E.
  coli
• Etiology of stomach cancer is unknown but linked
  to diet low in fruits and high in salt

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Small Intestine

• Most chemical digestion occurs here
• Nutrients absorbed into blood
• Longest organ of the alimentary canal
• Over 6 meters long 2.5 cm wide
• Pancreas produces digestive enzymes and alkaline
  solution rich in bicarbonate neutralizes acid
  chyme

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Small Intestine

• Liver produces bile bile salts digest fats
• Gall bladder stores bile until needed in small
  intestine
• Duodenum receives chyme from stomach and mixes
  with bile and digestive enzymes

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Small Intestine

• Completes digestion of starches that began in
  oral cavity
• Completes digestion of protein that began in the
  stomach
• Nucleases secreted from pancreases digest DNA and
  RNA
• Fats are surrounded by bile salts (emulsification)

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Diseases of Intestines

• Appendicitis acute and painful inflammation of
  the appendix/located off of the cecum
• Diverticulitis inflammation of little pouches
  or sacs formed when the mucosal lining pushes
  through the underlying muscle layer of the
  intestine/antibiotics

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Appendix
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DIVERTICULITIS
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Diseases of the Intestine

• Crohns Disease inflammatory disease of the
  intestine that most frequently affects young
  adults/ severe diarrhea and cramping
• Chronic Ulcerative Colitis inflammation of the
  colon/ diarrhea with pus, blood and mucus in the
  stool
• Surgery may result in a colostomy (artificial
  opening in the abdominal wall with a segment of
  the large intestine attached/waste collected in a
  bag

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Diseases of the Intestine

• Carcinoma of the Colon/Rectum leading cause of
  death from cancer in US and is the easiest to
  detect
• Irritable Bowel Syndrome spastic colon which
  often causes diarrhea, constipation, gas or
  abdominal pain/No ulcerations or tumors
• Dysentery acute inflammation of the colon

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Large Intestine

• 1.5 meters long 5 cm wide
• At large and small intestine junction is a cecum
  with an attached appendix (prone to infection)
• Primary function water absorption
• Causes ingested food to become more solid (feces)

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Large Intestine

• Feces composed of indigestable plant fibers and
  bacteria
• E. coli produces valuable vitamins (biotin, folic
  acid, B K vitamins)
• Rectum terminal portion of colon controlled by
  voluntary and involuntary sphincter
• Constipation occurs by lack of exercise or not
  enough plant fiber

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Disorders of the Digestive Tract

• Five Disorders Are
• Vomiting
• Diarrhea
• Constipation
• Hemorrhoids

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