30 Questions
What is the primary role of Gram-negative bacteria fimbriae in the intestinal tract?
Binding to glycoproteins on epithelial cells
How do bacteria in the human GI tract primarily contribute to nutrition and digestion?
Breaking down complex carbohydrates into simple sugars
What is the main impact of alterations in the GI flora due to poor nutrition or antibiotic use?
Increased risk of colonization by nonresident microbes
Which statement accurately reflects the role of some bacteria in the colon like Bacteroides?
Their metabolites contribute to carcinogenesis
What is the significance of bacterial flora in protecting their host from alien microbe infections?
Supporting the development of immunological tissues
How do bacteria in the human GI tract help prevent gastrointestinal diseases?
By guarding against colonization by harmful microbes
What temperature should raw seafood be held at according to the text?
Below 4°C
Which group of people is highly susceptible to virulent Listeria?
Pregnant women and the elderly
What is the mortality rate of immune compromised individuals, newborns, or very young individuals due to Listeria infection?
Approximately 30%
Which is the most pathogenic species causing listeriosis in humans?
Listeria monocytogenes
In what temperature range should cooked seafood be held according to the text?
Below 4°C or above 60°C
What can happen following invasion of macrophages by virulent strains of Listeria?
Multiplication resulting in disruption of cells and septicemia
What is the main characteristic of innate immunity?
It is nonspecific in nature
Which of the following is a physical component of skin defense?
Collagen
What is the role of dendritic cells in skin defense?
Phagocytize pathogens
How does sebum contribute to skin defense?
Keeps skin pliable and less likely to break or tear
Which of the following is a function of perspiration in skin defense?
Inhibits pathogen growth by drawing water from their cells
Why are epithelial cells lining body cavities considered a part of the immune defense?
They are living and provide a barrier
What is a commensal relationship?
A relationship where there is no apparent benefit or harm to either organism
Which bacterium is mentioned as the best known for associating with humans?
E.coli
Why do specific bacteria colonize specific tissues according to the text?
Because host tissues provide essential nutrients and growth factors for the bacterium
What characterizes tissue specificity of normal bacterial flora?
It is usually due to properties of both the host and the bacterium
Why is E.coli considered a commensal bacterium even though it may have parasitic or mutualistic characteristics?
Because it is well-studied and known to colonize the human intestinal tract
What explains tissue tropism in bacteria according to the text?
Host tissues provide essential nutrients and growth factors for the bacterium
What is the role of opsonins in the immune response?
Identify antigens for phagocytes
Which part of the immune system is responsible for screening tissues of the body for foreign antigens?
Lymphatic system
What is the composition of lymph, as mentioned in the text?
Similar to blood plasma
Which cells recognize and attack foreign antigens present in lymph nodes?
Lymphocytes
What is the function of antibodies in neutralizing toxins?
Neutralize toxins
From where are lymphocytes produced in the body?
Red bone marrow
Explore the attachment of Gram-negative bacteria to the epithelial cell surface in the intestinal tract and their benefits to the host through vitamin production and protection. Learn about the significant effects of bacterial flora in the GI tract.
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