1. Chapter 25 Digestive system infections Medgar Evers College, CUNY Bio 261 Prof. Santos

2. Basic anatomy of the human digestive system IIeum of small intestine Duodenum of small intestine Appendix Cecum Ascending portion of large intestine Anus Small intestine Large intestine Rectum Liver Gall- bladder Tongue Oral cavity Pharynx Esophagus Stomach Pyloric sphincter Cardiac orifice Mouth Esophagus Salivary glands Stomach Liver Pancreas Gall- bladder Large intestines Small intestines Rectum Anus Parotid gland Sublingual gland Submandibular gland Salivary glands A schematic diagram of the human digestive system Pancreas

3. Food is pushed along the digestive tract by peristalsis –Rhythmic waves of contraction of smooth muscles in the wall of the canal

4. In the oral cavity, food is lubricated and digestion begins –And teeth chew food into smaller particles that are exposed to salivary amylase, initiating the breakdown of glucose polymers

5. The region we call our throat is the pharynx –A junction that opens to both the esophagus and the windpipe (trachea) The esophagus –Conducts food from the pharynx down to the stomach by peristalsis

6. The stomach stores food –And secretes gastric juice, which converts a meal to acid chyme Gastric juice –Is made up of hydrochloric acid and the enzyme pepsin The lining of the stomach –Is coated with mucus, which prevents the gastric juice from destroying the cells

7. The small intestine –Is the longest section of the alimentary canal –Is the major organ of digestion and absorption The first portion of the small intestine is the duodenum –Where acid chyme from the stomach mixes with digestive juices from the pancreas, liver, gallbladder, and intestine itself

8. The pancreas produces proteases, protein-digesting enzymes –That are activated once they enter the duodenum

9. Pancreas Membrane-bound enteropeptidase Trypsin Active proteases Lumen of duodenum Inactive trypsinogen Other inactive proteases

10. The small intestine has a huge surface area –Due to the presence of villi and microvilli that are exposed to the intestinal lumen The enormous microvillar surface –Is an adaptation that greatly increases the rate of nutrient absorption

11. The large intestine, or colon –Is connected to the small intestine A major function of the colon –Is to recover water that has entered the alimentary canal The wastes of the digestive tract, the feces –Become more solid as they move through the colon –Pass through the rectum and exit via the anus

12. Normal microbiota of the digestive system Different species colonize the mouth depending on their ability to attach to specific receptors. Dental plaque consists of many bacteria of different species attached to the teeth or each other. Anaerobic bacteria are also present.

13. Bacterial infections of upper digestive system DiseaseCause symptomspathogene sis treatment Dental caries or tooth decay * incubation period is 1 to 24 months Streptococcus mutans Severe pain, discoloration of tooth or breakage Glucan is produced from sucrose. This is needed for dental caries production Restrict sugar, fluoride in toothpaste see dentist regularly

14. Bacterial infections of upper digestive system DiseaseCause symptomspathogene sis treatment Periodontal disease Dental plaqueBleeding, sensitive gums, bad breath, loosening of the tooth, Bacteria produces inflammatory response, plaque forms, widens and anaerobic bacteria grow, toxins and enzymes degrade tissue Avoid buildup of plaque and surgery if needed

15. Bacterial infections of upper digestive system DiseaseCause symptomspathogene sis treatment Trench mouth (acute necrotizing ulcerative gingervitis) A spirochete of genus Treponema Fever, painful bleeding gums, foul mouth odor Tissue destruction, ulceration and tissue invasion by spirochete. Antibiotic treatment

16. Bacterial infections of upper digestive system DiseaseCause symptomspathogene sis treatment Helicobacter pylori gastritis H. pyloriVomiting, belching, abdominal pain and tenderness and bleeding if ulcer or cancer associated Pathogen survives acidity of stomach, penetrates mucus, inflammatory response, thinning of mucus can occur if ulcer forms Antibiotics and medication to suppress acid formation

17. H. pylori Gram – Microaerophile Multiple polar flagella for motility Produces urease to neutralize acidity of stomach Buries itself on the mucus layer to survive

18. Viral infections of upper digestive system DiseaseCause symptomspathogene sis treatment HerpesHSV Type 1 Fever, sore throat, pain in lip followed by blisters Virus replicates in the epithelium, an immune response follows, but virus hides in sensory nerves Anti viral medicatio n such as acyclovir, penciclovir

19. Viral infections of upper digestive system DiseaseCause symptomspathogene sis treatment Mumps *incubation period is 15 to 21 days Mump virusFever, headache, loss of appetite, painful swollen parotid glands, painful enlarged testicles, pelvic pain in women Virus replicates in the upper respiratory tract and then travels to parotid glands, inflammatory response occurs An effective attenuated vaccine since 1967 has been in place since then.

20. Bacterial infections of lower digestive system DiseaseCause symptomspathogene sis treatment CholeraVibrio cholerea Massive diarrhea, vomiting, muscle cramps Exotoxins that cause excessive excretion of electrolytes by the intestinal epithelium; leads to dehydration and shock Purification of water supply, rehydration with electrolyte and glucose

21. mumps Only one antigenic type of the mumps is known.

22. Bacterial infections of lower digestive system DiseaseCause symptomspathogene sis treatment ShigellosisSpecies of shigella Fever, dysentery, vomiting headache, stiff neck, painful joints Pathogen invades and multiplies within the intestinal epithelium Antibiotics such as ampicillin, sanitary measures,

23. Bacterial infections of upper digestive system DiseaseCause symptomspathogene sis treatment Gastroenteritis caused by E.coli E. coliVomiting and diarrhea, sometimes dysentery (crampy abdominal pain and bloody diarrhea) Attachment, toxins, invasion of intestinal epithelium, loss of microvilli Bismuth compound treatment, sanitary conditions, replacement of fluids loss

24. Bacterial infections of lower digestive system DiseaseCause symptomspathogene sis treatment Salmonellosis Salmonella enterica Diarrhea, vomiting, Invasion and penetration of tissue, inflammatory response No treatment unless tissue invasion then antimicrobial agent

25. Bacterial infections of lower digestive system DiseaseCausesymptomspathogenesi s treatment Campylobac teriosis Campylobacter jejuni Diarrhea, fever, abdominal cramps, nausea, vomiting, bloody stool Low infecting dose, pathogen multiplies within and beneath the epithelial cells, inflammatory response Sanitary measures, and no antimicrobial treatment

26. Viral infections of lower digestive system DiseaseCause symptomspathogene sis treatment Hepatitis A (acute and rarely leads to long term liver or permanent damage) Nonenveloped ss RNA picorna virus Fatigue, fever, loss of appetite, nausea, right sided abdominal pain, dark colored urine Viral replication and damage restricted to liver. How it gets there is still being investigated Inactivated vaccine

27. Viral infections of lower digestive system DiseaseCause symptomspathogene sis treatment Hepatitis B (infected blood or body fliud/oral) Enveloped ds DNA hepadnavirus More severe than A, progressive liver damage, can lead to cirrhosis and cancer HBV is carried to liver by bloodstream, attaches and invades liver cells Combined Hepatitis A and B vaccine

28. Viral infections of lower digestive system DiseaseCause symptomspathogene sis treatment Hepatitis C (most commonly transmitted by sharing needles) Enveloped ss RNA flavivirus Few or no symptoms, progressive liver damage or cancer in 10 to 20% of cases Liver cells are infected and replication occurs, inflammatory response occurs No vaccine but one should avoid alcohol use and anti viral medication if needed

29. 2 other viral infections of the lower 1- rotaviral gastroenteritis, most common cause of viral gastroenteritis in children and infants 2- noroviral gastroenteritis, most common cause of viral gastroenteritis in the USA

30. Protozoan infections of lower digestive system DiseaseCause symptomspathogene sis treatment GiardiasisGiardia lamblia, a pear shaped protozoan Flatulence, nausea, vomiting, diarrhea, abdominal cramps, weight loss Host immune response to attachment of pathogen to epithelial lining Antimicrobial medications such as atabrine or flagyl

31. Protozoan infections of lower digestive system DiseaseCause symptomspathogene sis treatment CryptosporidiosisCryptosporidium parvum Fever, loss of appetite, nausea, crampy abdominal pain, watery diarrhea lasting 10 to 14 days Invasion of epithelial cells, inflammatory response No effective treatment exists but sanitary conditions should be kept, pasteurization of beverages

32. Protozoan infections of lower digestive system DiseaseCause symptomspathogene sis treatment Cyclosporiasis Cyclospora cayetanensis Fatigue, loss of appetite, vomiting, watery diarrhea, weight loss Very little is known Bactrim, Septra antimicrobial agents, boil water before drinking

33. Protozoan infections of lower digestive system DiseaseCause symptomspathogene sis treatment AmebiasisEntamoeba histolytica Diarrhea, abdominal pain, blood in feces Ingested cysts liberate the pathogen, reach large intestine, feed on mucus and cells lining the intestine, and sometimes they penetrate the lining by using enzymes Metronidazole or paromomycin