Podcast
Questions and Answers
Match the following diseases with their causes:
Match the following diseases with their causes:
Mumps = Viral infection Cholera = Bacterial infection Thrush = Fungal infection Giardiasis = Protozoan infection
Match the following mycotoxins with their associated conditions:
Match the following mycotoxins with their associated conditions:
Aflatoxin = Liver cirrhosis and liver cancer Ergotoxin = Gangrene and hallucinations Claviceps purpurea = Grains contamination Aspergillus flavus = Peanut contamination
Match the following symptoms with the relevant poisoning:
Match the following symptoms with the relevant poisoning:
Ergot poisoning = Loss of muscle coordination Aflatoxin poisoning = Liver dysfunction Convulsive ergotism = Hyper-excitability and ataxia Candidiasis = Oropharyngeal discomfort
Match the following diseases with their prevention methods:
Match the following diseases with their prevention methods:
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Match the following fungal diseases with their specific types:
Match the following fungal diseases with their specific types:
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Match the following groups at risk with the fungal disease:
Match the following groups at risk with the fungal disease:
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Match the following bacterial diseases with their characteristics:
Match the following bacterial diseases with their characteristics:
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Match the following terms to their definitions:
Match the following terms to their definitions:
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Match the following types of poisoning with their causative fungi:
Match the following types of poisoning with their causative fungi:
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Study Notes
Structure and Function of the Digestive System
- The gastrointestinal (GI) tract, also known as the alimentary canal, includes the mouth, pharynx, esophagus, stomach, small intestine, and large intestine.
- Accessory structures that aid digestion consist of teeth, tongue, salivary glands, liver, gallbladder, and pancreas.
- Over a lifetime, approximately 25 tons of food pass through the GI tract.
Immunity of the Digestive System
- About 80% of the immune system resides in the intestinal tract.
- Saliva contains lysozyme, immunoglobulins, and phagocytes that assist in immunity.
- Gut-associated lymphoid tissue (GALT) includes lymph nodes and Peyer’s patches, crucial for immune response.
- IgA and mucus play significant roles in protecting the digestive system.
- Bacteriocins, which are toxins, help target harmful bacteria.
Normal Microbiota of the Digestive System
- Saliva contains millions of bacteria per milliliter, with both aerobic and anaerobic types colonizing surfaces.
- The stomach has minimal microorganisms due to high acidity from HCl.
- In the small intestine, Paneth cells produce defensins that combat pathogens.
- The large intestine hosts around 100 billion bacteria per gram of feces, predominantly anaerobes.
Microbial Colonization Across the Digestive System
- The esophagus, stomach, and duodenum are nearly free of microbes due to rapid transport and peristalsis.
- The tongue, teeth, jejunum, ileum, colon, and rectum have a higher concentration of microorganisms, mainly viridans streptococci.
- In the lower small intestine and colon, various beneficial microbiota prevent unwanted microbial intrusion into the bloodstream.
Diseases of the Digestive System
- Common bacterial diseases include dental caries, gastroenteritis, and bacterial dysentery.
- Fungal diseases include thrush and aflatoxin poisoning.
- Protozoan infections such as amebic dysentery and giardiasis also affect the digestive system.
- Viral diseases encompass mumps and hepatitis A-E.
Bacterial Diseases
Dental Plaque
- Dental plaque is a biofilm that forms on tooth surfaces within 24 hours post-cleaning, marking the initial step towards tooth decay.
- Positive charge of salivary proteins facilitates plaque formation, primarily through Streptococcus mutans.
Dental Caries (Tooth Decay)
- The most prevalent infectious disease in developing countries often linked to refined sugars in diets.
- Untreated caries can lead to significant tooth damage and abscesses.
- Key bacteria include Streptococcus mutans and Lactobacillus species.
Food Poisoning
- Annually, about 76 million cases of food poisoning occur in the U.S., predominantly mild and self-limiting.
- Foodborne diseases can be classified as intoxications (due to toxins) or infections (due to pathogen multiplication).
- Symptoms typically present as nausea, vomiting, and diarrhea.
Staphylococcal Food Poisoning
- Caused by Staphylococcus aureus, which produces heat-stable enterotoxins in food.
- Common sources include egg products and poultry; symptoms present 1-6 hours post ingestion.
Keeping Food Safe
- Thorough cooking, avoiding cross-contamination, and practicing good hygiene are essential for food safety.
EHEC and Other E.coli Infections
- E.coli O157:H7, a notable strain, can lead to severe bloody diarrhea and complications like hemolytic uremic syndrome.
- Other strains include ETEC (watery diarrhea) and EIEC (invades intestinal epithelium).
Rotavirus
- Major cause of childhood morbidity in developing nations, with fecal-oral transmission leading to severe diarrhea and vomiting.
- Prevention involves sanitation and vaccination, such as Rotateq.
Diagnosis and Treatment of Food Poisonings
- Diagnoses typically include laboratory tests and stool cultures.
- Treatment includes maintaining hydration and symptom management, avoiding anti-diarrheal medications when necessary.
Bacillary Dysentery (Shigellosis)
- Caused by Shigella species; it is highly infectious and diagnosed via PCR tests.
Viral Diseases
Mumps
- Transmitted through respiratory droplets, causing parotitis and potential complications such as sterility and encephalitis.
- Vaccination via the MMR vaccine is important for prevention.
Mycotoxin Poisoning
- Ergot poisoning results from Claviceps purpurea, found in grains and leading to gangrene and hallucinations.
- Aflatoxin poisoning, from Aspergillus flavus on peanuts, can lead to liver cirrhosis and cancer.
Thrush (Oropharyngeal Candidiasis)
- Caused by Candida albicans, often affects newborns and the immunocompromised, transmitted via fomites or imbalance of oral flora.
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Description
Explore the structure and function of the gastrointestinal system in this quiz. Delve into the various components of the GI tract, including the accessory structures and their roles. Understand how the digestive system contributes to overall health, including its impact on immunity.
