Eight Sections:

1. Mouth
2. Pharynx
3. esophagus
4. stomach
5. small intestine
6. large intestine
7. rectum
8. anus

• Salivary glands
• Liver
• Gallbladder
• Pancreas

"remember tube within a tube"

• Mucus: draps debrie and invaders
• Secretory IgA: attack specific invaders
• Peristalsis: Movement of food through your gut, constantly moving so pathogens can't easily get in.
• Fluids within antimicrobial properties: saliva, stomach fluid, bile: solution that breaks up fats/cell membrane.
• GALT: Gut Associated Lymphoid Tissue
• Microbial Antagonism-normal biota 

(GALT)

Gut Associated Lymphoid Tissue 

• Tonsils, adenoids, lymphoid tissue in esophagus, peyer's patches, appendix
• In these areas its draining excess fluids which can contain bacteria.. like a filtering system. WBC will then attack this debrie. 

-Large variety

Oral cavity has about 550 know species of microbes

-Esophagus and stomach much more sparsely populated. The esophagus is constantly moving and the stomach has a low PH which make it hard for bacteria to adhere and flourish. 

-Large Intestine: Billions of microorganisms

commensal population: one organism will benefit but the host does not benefit ( only the biota are benefitting). 

• Tooth and Gum Infections: If left undisturbed, normal biota biofilm eventually contains anaerobic bacteria.
• Biofilm: Slim that helps the bacteria to attach.
• Anaerobic Bacteria: Thrive with out oxygen (produce acids which destroy enamel).
• Damage soft tissues and bone (periodontium)
• Carbohydrates in oral cavity can result i break down of dentin.
• Bacteria have frimbrae and slime layers to adhere which could also be virulence factors. 
• Sugar helps bactria stick to teeth. 

Dental Caries

(tooth decay)

Most common infectious disease of human beings

• Symptoms: Range from minor disruption in enamal to comlete destruction of enamal and deeper layers. 
• if it reaches dentin=cavity, pulp=nerve, can also affect bone. 
• Deeper lesions can result in infection to soft tissue inside the tooth leading to a toothache.

The bacteria 

• Streptococcus Mutans
• Streptococcus Sobrinus

Heliobacter Pylori thrive in the acidic environment of the stomach and causes:

• Gastritis: Sharp or burning pain emanating from the abdomen. (inflammation)
• Gastric Ulcers: Are actual lesions in the mucosa of the stomach.
• Duodenal Ulcer: Lesio n in the uppermost portion of the small intestin. (duodenum)-too much acid emptying in there. 

Long term infection with H. Pylori might be a contributing factor to stomach cancer!!

Sever ulcers can be accompanied by bloody stools, vomiting or both. 

• In the U.S, up to a third of all cases transmitted by contaminated food.
• Most cases are self-limiting and do no require reatment. Will correct themselves but can cause sever dehyfration.
• Some ( E. Coli 0157:H7) can be devastating. 

Salmonellosis: can be severe

• Undercooked poultry and eggs (caused from S. Enterica)
• Reptile and rodent feces (same bacteria as above)
• Elevated body temperature and septicemia
• Gastroenteritis (stomach and intestine mucosa)-inflammation.
• Vomiting, diarrhea, and mucosal irritation
• symptoms usually spontaneouly subside after 2 to 5 days
• treated with fluid and electrolyte replacement

Acute Diarrhea cause by E.Coli

0157:H7 (EHEC)

• Most virulent strain of E. coli
• Enterohemorrhagic E. coil:Gut hemorraging(blood in gut)
• Symptoms range from mild gastroenteritis with fever to bloody diarrhea (inner linings falling off).
• Can also cause neurological symptoms such as blindness, seizure and stroke. 

Acuter Diarrhea Caused by E. coli

Four other categories:

• Enterotoxigenic
• Enteroinvasive
• Enteropathogenic
• Enteroaggregative

Enterotoxigenic E. Coli 

(ETEC)

Enteroinvasive E. Coli

(EIEC)

-Invade gut mucosa and cause widespread destruction.

-Blood and pus found in stool

-signifigant fever

Enteropahtogenic E. coli

(EPEC)

• Profuse, watery diarrhea
• fever and vomiting also common
• Produce effacement of gut surfaces (linings of gut fall off).

Enteroaggregative E. coli

(EAEC)

Can cause chronic diarrhea in young children and in AIDS patients. 

-Over a week of diarrhea

-Due to a compromised immune system

Acute Diarrhea caused by Clostridium difficile

(C-Diff)

• Causes pseudomembranous Colitis
• Major cause of diarrhea in hospitals
• Able to superinfect the large intestine when drugs have disrupted the noram biota. (can cause widespread infection)
• Produces two enterotoxins (toxins A and B) that can cause areas of necrosis in the wall of the intestine.
• Abdominal cramps, fever, and leukocytosis (↑ wbc)

Acute Diarrhea Caused by 

Cryptosporidium

Intestinal protozoan of...

• mammaks, birds, reptiles
• ingest food contaminated with feces containing oocysts.
• Oocyst "hatches" and invades gut epithelial cells and remains inside them!!
• Headache, sweating, vomiting, severe vomiting, sever abdominal cramps, and diarrhea-persistant doesnt go away. 

Is a Intestianl protozoan bacteria of

• Mammals, birds, reptiles
• Ingest food contaminated with feces containing oocysts
• Oocyst "hatches" and invades gut epithelial cells and reamins inside them.

Food Poisoning

by

staphylococus aureus exotoxin

Foods that are left unrefrigerated for a fews hours can get contaminated with bacteria.

• Toxins do not noticeable alter the food's taste or smell.
• Heating the food after toxin production may not prevent disease.
• Symptoms: cramping, nausea, vomiting, and diarrhea
• Rapid recovery: usually within 24 hours. 

• Lasting longer than 14 days
• Infectious or noninfectious
• AIDS patients suffer from it due to opportunisitic infections. If being treated with many strong medications-which can wipe out good biota. 
• Several microbes can be responsible for infection. 

Hepatitis

liver inflammation

• Viral liver infection
• the liver is responsible for getting rid of waste products. 
• Is inflammatory disease, necrosis of hepatocyes and swells and disrupts liver architecture (which is important to its function...special shape needed)
• Cant excrete bile pigments
• Causes jaundice ehrn bilirubin accumulates in the blood and tissues.( the liver can get rid of the hem-pigment)
• Most commonly transmittled through BLOOD CONTACT. 
• Vaccinations available for A, B but not C
• Most common treatment is with INTERFERON- which is like a cell messenger to warn other cells of the infection so they can prepare themselves. 

Hepatitis A Virus

(HAV)

• Is a RNA enterovirus (virus that gets into our body). 
• Hep conains RNA type for genetic component
• Milder and shorter term than other forms.
• Flulike  symptoms
• In some cases, may include haundice and swollen liver 
• Darkened urine often see (which represents build up of toxins)
• Not oncogenic: does not cause tumors/cancer
• Complete uncomplicated recovery
  

Hepatitis B Virus 

(HBV)

• DNA virus
• Fever, chills, makaise, anorexia, abdominal discomfort, diarrhea, and nausea.
• Rashes may appear
• Arthritis may occur

-Can be serious and life-threatening

-Some patients develop glomerulonephritis=inflammation of the kidney. And arterial inflammation.

• Complete liver regeneration and restored function occur in most patients
• Small number of patients develop chronic liver disease (necrosis:death of tissues or Cirrhosis: liver scarring.

Heapatitis C Virus

(HCV)

• RNA virus (worst of all heps)
• "Silent epidemic" because takes many years to cause noticeable symptoms.
• Liver failure (most common cause of liver transplants in US).
• fairly aggressive treatments can work
• Share many symptoms of HAB but is more likely to become chronic
• CANCER MAY ALSO RESULT (oncogenic). 
• Many of the diseases we have discussed are diagnosed by ELISA or RIA or WB. 

Infectious Diseases Affecting the 

Urogential System

Urinary tract: 

• includes the kidneys, ureters, bladder, and urethra
•  Defenses:
• Flushing action of urine- constantly flushes out bacteria. 
• Desquamation of epithelial cells: sloughed off cells of the urethra. 
• Acidity of urine
• Antibacterial proteins in urine
• Secretory IgA
• Microbial antagonism

Defenses of the Genital System:

-Male: testes, epididymis, vas deferens, prostate, scrotum, and penis. 

-Female: Uterus, fallopian tubes, ovaries, and vagina

• Defenses vary over  the lifetime of the woman
• -childhood and adter menopause: muscous is the major defense (secretory IgA).
• -during reproductive years: changes in PH which occurs while the woman has menstrual cycles. 

• Normal Biota of the Urinary Tract
• -nonhemolytic streptococci, staphylocci, corynebacteria, and lactobacilli.
• 
  Normal Biota of the Male Genital Tract(same as above)
• -same as described for uretha, since the urethra is the terminal "tube".
• Normal biota of the female genital tract
• -the vagina harbors a normal population of microbes
• Lactobacillusi species
• candida albicans at low levels (fungus)
• provides microbial antagonism

Urinary Tract Infections

(UTIs)

• Urine is a good growth medium for many microorganisms, lots of nitrogenous wastes.
• Reduced urine flow, or accidental introduction of bacteria into the bladder can result in cystitis=inflammation of bladder
• If the infection also affects the kidneys it is called pyelonephritis (kidney and pelvis inflammtion)
• An infection only in the uretha: urethritis: inflammation of the uretha.
• Most commonly caused by E. coli
• Preventative hygiene and drink cranberry juice.