Microbiota and Normal Flora Overview

<p>They can convert harmless substances into carcinogenic derivatives. (A)</p> Signup and view all the answers

<p>When individuals are immunocompromised. (C)</p> Signup and view all the answers

<p>Conjunctiva (A)</p> Signup and view all the answers

<p>Normal flora (B)</p> Signup and view all the answers

<p>Streptococcus pneumoniae (C)</p> Signup and view all the answers

<p>High acidity and gastric enzymes (A)</p> Signup and view all the answers

<p>Large intestine (D)</p> Signup and view all the answers

<p>Usually sterile (C)</p> Signup and view all the answers

<p>Lactobacillus spp. (D)</p> Signup and view all the answers

<p>They become pathogenic (C)</p> Signup and view all the answers

<p>Bacteria, fungi, protozoa, and viruses (D)</p> Signup and view all the answers

<p>It includes bacteria, viruses, fungi, and parasites (D)</p> Signup and view all the answers

<p>Opportunistic microbes can cause infections (B)</p> Signup and view all the answers

<p>Microorganisms that reside in the body without causing harm (C)</p> Signup and view all the answers

<p>Hair color (D)</p> Signup and view all the answers

<p>2 kg (B)</p> Signup and view all the answers

<p>At birth (B)</p> Signup and view all the answers

<p>Contributes to the host's defense and health (A)</p> Signup and view all the answers

<p>They may not be able to compete with resident normal flora. (C)</p> Signup and view all the answers

<p>Hair Follicles (D)</p> Signup and view all the answers

<p>Aerobic Bacteria (A)</p> Signup and view all the answers

<p>Production of sweat and oil (C)</p> Signup and view all the answers

<p>It is primarily found in sweat glands and hair follicles. (D)</p> Signup and view all the answers

<p>Staphylococcus epidermidis (C)</p> Signup and view all the answers

<p>Staphylococcus aureus (A)</p> Signup and view all the answers

<p>They occupy niches that could otherwise be taken by pathogens. (B)</p> Signup and view all the answers

<p>Keeping the pH acidic to prevent infections (C)</p> Signup and view all the answers

<p>Vitamin K (B)</p> Signup and view all the answers

<p>By competing with pathogens for resources (A)</p> Signup and view all the answers

<p>Proteobacteria (A), Actinobacteria (D)</p> Signup and view all the answers

<p>Nonobese mice become obese (B)</p> Signup and view all the answers

<p>Killing harmful pathogens and competing for nutrients (A)</p> Signup and view all the answers

<p>Firmicutes and Bacteroidetes (A)</p> Signup and view all the answers

<p>Offering resistance to infectious diseases (A)</p> Signup and view all the answers

Microorganisms, mainly bacteria, that normally live in and on the human body.

Microbiota that are always present in the body, even in healthy individuals.

Microorganisms that are temporarily present in the body, often due to environmental exposure or dietary changes.

The composition of microbiota varies between individuals due to factors like age, diet, and geographic location.

Microbiota play a critical role in protecting against harmful pathogens. They act as a barrier and keep the body healthy.

The number of microbial cells in the human gut is significantly larger than the number of human cells in the body.

Imbalances in microbiota can lead to the development of various diseases, including infections and autoimmune disorders.

Sterile at birth, the human body gradually acquires its microbiota from the environment. This process starts from the moment of birth.

Microorganisms that temporarily live on and within humans, coming from the external environment and attracted to moist, warm areas.

The main reasons why transient microbiota are temporary include being washed away, unable to compete with existing microbes, killed by resident flora, or unable to survive in the environment due to pH or bodily secretions.

Microorganisms residing in specific locations on a human body that are constantly present.

Resident microbiota are found in areas of the body that are exposed to the external environment, where they can interact with the outside world.

The skin, eyes, ears, respiratory tract, mouth, gastrointestinal tract, and urogenital tract are all areas where resident microbiota can be found.

Staphylococcus epidermidis is a common aerobic bacterium found on the skin, making up 90% of the microbiota. Staphylococcus aureus is another common aerobic bacterium found on the skin, while Cutibacterium acnes (formerly Propionibacterium acnes) is an anaerobic bacterium found in deeper skin layers and hair follicles.

While generally harmless, skin microbiota can cause bloodstream infections if the skin is penetrated, allowing bacteria to enter the circulatory system.

The conjunctiva of the eye is primarily inhabited by S. epidermidis, followed by S. aureus, C. diphtheroids, and S. pneumoniae. Some skin normal flora are also present but in smaller amounts.

The conjunctiva is a thin transparent membrane that lines the inside of the eyelids and covers the white part of the eye. It's protected from bacterial colonization by tears, mucus, and oil.

The middle and inner ear are typically free of microorganisms, while the outer ear and auditory canal contain the same normal flora as the skin. Coughing, sneezing, or blowing your nose can push these microbes into the middle ear, leading to infection.

The upper respiratory tract, which includes the nose and throat, harbors many microorganisms. Some are part of the normal flora, some are opportunistic, and others are transients.

Streptococcus pneumoniae is a common bacterium found in the nasopharynx. While usually harmless, it can cause pneumonia in individuals with weakened immune systems or the elderly.

The lower respiratory tract, including the lungs, is usually sterile because the mucous membranes effectively trap and remove microbes.

The oral cavity, or mouth, contains a diverse community of microorganisms, including C. diphtheroides, S. aureus, and S. epidermidis. These bacteria are generally found in the mouth. Yeasts, molds, protozoa, and viruses may also be present.

S. mutans, a bacterium that thrives in the mouth, can contribute to dental caries and gingivitis if dental hygiene is poor. Following dental surgeries, there's a risk of bloodstream infection that can lead to endocarditis.

The stomach harbors very few bacteria due to the presence of gastric enzymes and acidic pH. The upper small intestine has very limited normal flora because bile kills most bacteria. The lower small intestine has a larger number of normal flora.

The suppression of potentially harmful microorganisms in the gut by a diverse and healthy microbiota.

The process where gut microbes influence the development and function of the immune system.

When certain microbes in the gut influence the balance of different types of immune cells (Th1, Th2, and Th17), affecting the immune response.

A condition where a normally harmless bacteria like Clostridioides difficile overgrows in the gut, causing inflammation and colitis, often after antibiotic use.

A medical procedure where healthy fecal matter from a donor is transplanted into the gut of a patient struggling with colitis, restoring a balanced microbiome.

The vagina has an acidic pH to prevent growth of harmful organisms.

The vagina normally has a population of beneficial bacteria that prevent infections. These are called normal flora.

These areas are sterile, meaning they have no resident microbes. This is essential in protecting important organs and fluids.

Microbiota, mainly bacteria, protect us from harmful pathogens.

Microbiota help the immune system develop in newborns.

Microbiota in the gut help digest food and produce essential nutrients, like Vitamin K.

The number of microbial cells in the human gut is significantly larger than the number of human cells.

Changes in gut microbiota can contribute to diseases like obesity and inflammatory bowel disease.