Chapter 20: Infectious Diseases Affecting the Gastrointestinal Tract- Part 1

Question 1

Defenses against infection in the GI tract

Answer 1

Mucus
Saliva
Stomach acid
Bile (antimicrobial)

Question 2

GALT

Answer 2

Gut associated lymphoid tissue

Question 3

Examples of GALT

Answer 3

Tonsils and adenoids in the oral cavity and pharynx
Small layers of lymph tissue in esophagus
Peyer’s patches in small intestine

Question 4

Lactoferin

Answer 4

Bacteriocide / fungicide

High levels in breast milk

Question 5

What amount of species colonizes the oral cavity?

Answer 5

Relatively few

Question 6

What is the most common species that colonizes the mouth?

Answer 6

Streptococcal

Question 7

Why do relatively few bacteria colonize in the mouth?

Answer 7

Mucus membranes and it is a shedding surface

Question 8

Since the teeth are a non-shedding surface…

Answer 8

Large numbers of bacteria can collect and form biofilm

Question 9

Masses of bacteria on teeth are termed..

Answer 9

Dental plaque

Question 10

There are ______ bacteria per gram of plaque

Answer 10

100 billion

Question 11

_____ number of bacteria colonize upper small intestine

Answer 11

Small

Question 12

Predominant organisms of upper small intestine

Answer 12

Aerobic and facultative Gram negative bacilli and some streptococci

Question 13

Large intestine contains very ____ numbers of organisms

Answer 13

High

Question 14

There are approximately ___ bacteria per gram of feces

Answer 14

100 billion

Question 15

High population of bacteria in large intestine is due to…

Answer 15

Abundance of nutrients in feces

Question 16

What bacteria predominate population in the large intestine?

Answer 16

Escherichia coli and other enterobacteria

Question 17

E coli and other fecal bacteria are an important source of…

Answer 17

Opportunistic infections

Especially of urinary tract

Question 18

Normal intestinal flora prevent..

Answer 18

Pathogenic colonization of large intestine

Question 19

What is the most common disease of human beings?

Answer 19

Dental carries

Question 20

As many as ___% of US population over 65 have lost all of their teeth

Answer 20

47

Question 21

Dental caries symptoms

Answer 21

Usually advanced before symptoms arrive

• Throbbing pain
• Noticeable discoloration, roughness or defect in tooth
• Tooth can break while chewing

Question 22

Causative agent of dental caries

Answer 22

Streptococcus mutans (most common)

Question 23

Streptococcus mutans metabolism

Answer 23

Thrive in acidic conditions, produce lactic acid from sugar metabolism

Question 24

Streptococcus mutans produce ______ from sucrose

Answer 24

Glucans

essential for production of dental caries

Question 25

Pathogenesis of dental caries begins with..

Answer 25

Adherance of bacteria to specific receptors on teeth

Question 26

After bacterial cells adhere to receptors on teeth…

Answer 26

Glucans bind organisms together and to tooth

-Formation of cariogenic plaque

Question 27

After a plaque forms…

Answer 27

Dietary sugar causes a drop in pH

Question 28

What does the acidic environment of the mouth cause?

Answer 28

Calcium phosphate in teeth to dissolve, which creates pits and fissures for colonization

Question 29

Periodontal Disease

Answer 29

Gum disease

Microorganisms forming a film in the gingival crevice

Question 30

Symptoms of Helicobacter pylori gastritis

Answer 30

Range from belching to vomiting,
Mostly asymptomatic,  occur when condition is complicated with ulcers or cancer
-Abdominal pain
-Tenderness 
-Bleeding

Question 31

Helocobacter pylori characteristics

Answer 31

Short
Spiral 
Gram negative
Microaerophile (small amount of oxygen)
Multiple polar flagella

Question 32

H pylori have urease, which…

Answer 32

Is used to turn urea into CO2 and ammonia, CO2 causes belching and ammonia buffers stomach acid

Question 33

H pylori survive the extreme acidity of the stomach because they are..

Answer 33

Able to neutralize the environment

Question 34

H pylori uses flagella to..

Answer 34

Corkscrew through mucosal lining

Question 35

Corkscrew effect causes..

Answer 35

Inflammatory respinse

Question 36

After the inflammatory response begins,

Answer 36

Mucus production decreases (stomach not protected from acidic environment)

Question 37

H pylori can persist for..

Answer 37

Years

Possibly a lifetime

Question 38

H pylori infections are likely _______ route

Answer 38

Fecal-oral

-Flies also capable to transmission

Question 39

What percentage of US population is infected with H pylori?

Answer 39

20%

Question 40

Almost ____ of people one 75 are infected with H pylori

Answer 40

80%

Question 41

Rates of H pylori are are higher in what groups?

Answer 41

Lower socioeconomic groups

Question 42

Prevention of H pylori gastritis

Answer 42

No proven prevention measures

Question 43

H pylori can usually be eradicated with..

Answer 43

Combined antibiotic treatment (Penicillin, amoxicillin)

Question 44

H pylori: medication is also used to…

Answer 44

Inhibit production of stomach acid