Podcast
Questions and Answers
Which factor least influences the composition of the human microbiome across different body sites?
Which factor least influences the composition of the human microbiome across different body sites?
- pH levels, exemplified by the comparatively acidic environment of the vagina.
- Exposure to variable external conditions, including humidity, salinity, and extreme temperatures on the skin.
- Consistent and invariable internal body temperature maintained regardless of external conditions. (correct)
- Oxygen availability, such as the aerobic environment of the lung versus the anaerobic conditions of the GI tract.
Why are microorganisms relatively sparse in the adult stomach compared to the ileum?
Why are microorganisms relatively sparse in the adult stomach compared to the ileum?
- Peristaltic movements rapidly flush out microbes before they can establish colonies.
- The acidic nature of the stomach, due to gastric enzymes, creates an inhospitable environment for many microbes. (correct)
- A thick mucus layer in the stomach prevents microbes from adhering to the stomach lining.
- The stomach's epithelial lining secretes antibodies that inhibit bacterial colonization.
In bacterial vaginosis (BV), what microbial shift occurs that disrupts the normal vaginal flora?
In bacterial vaginosis (BV), what microbial shift occurs that disrupts the normal vaginal flora?
- An increase in the population of _Lactobacillus_ species enhances the acidity of the vagina, leading to irritation.
- A replacement of protective _Lactobacillus_ species by pathogenic species such as _Gardnerella vaginalis_. (correct)
- An increase in gram-positive cocci elevates the pH, fostering a beneficial environment of the adult vagina.
- A decrease in _Candida albicans_ allows for the overgrowth of protective bacterial species.
In what way do tears protect the conjunctiva of the eye from extensive bacterial colonization?
In what way do tears protect the conjunctiva of the eye from extensive bacterial colonization?
How does the consumption of a diet high in meat impact the gut microbiota composition compared to a vegetarian diet?
How does the consumption of a diet high in meat impact the gut microbiota composition compared to a vegetarian diet?
Why is Streptococcus mutans specifically significant in the context of oral cavity flora?
Why is Streptococcus mutans specifically significant in the context of oral cavity flora?
What is the primary reason that transient flora are unable to permanently colonize the skin?
What is the primary reason that transient flora are unable to permanently colonize the skin?
An individual is diagnosed with a bloodstream infection originating from the skin. Which of the following organisms, commonly found as part of the normal skin flora, is the most likely cause?
An individual is diagnosed with a bloodstream infection originating from the skin. Which of the following organisms, commonly found as part of the normal skin flora, is the most likely cause?
Why does a viral infection of the upper or middle respiratory tract frequently predispose an individual to Streptococcus pneumoniae infection?
Why does a viral infection of the upper or middle respiratory tract frequently predispose an individual to Streptococcus pneumoniae infection?
In the adult female genitourinary tract, how does Lactobacillus acidophilus contribute to maintaining a healthy vaginal environment?
In the adult female genitourinary tract, how does Lactobacillus acidophilus contribute to maintaining a healthy vaginal environment?
Flashcards
Common sites of endemic flora
Common sites of endemic flora
Sites that are in contact or communication with the external world.
Skin's common microbes
Skin's common microbes
Gram-positive cocci and bacilli.
Pneumonia's precursor
Pneumonia's precursor
Streptococcus pneumoniae frequently follows a viral respiratory infection.
Vaginal Flora's Role
Vaginal Flora's Role
Signup and view all the flashcards
Eye's defense against flora
Eye's defense against flora
Signup and view all the flashcards
Skin Flora Types
Skin Flora Types
Signup and view all the flashcards
Mouth's Microbial Mix
Mouth's Microbial Mix
Signup and view all the flashcards
Dental Decay Culprit
Dental Decay Culprit
Signup and view all the flashcards
Large Intestine Flora
Large Intestine Flora
Signup and view all the flashcards
Vaginal Acidity Source
Vaginal Acidity Source
Signup and view all the flashcards
Study Notes
Endemic Flora Overview
- Endemic flora, also known as normal flora, commonly inhabit body sites in contact with the external world.
- The human microbiome is a dynamic protective barrier; knowledge of its composition, function, and stability has grown significantly in recent decades.
- Different body sites present distinct ecological niches.
Body Site Examples
- Lungs: Highly aerobic environment.
- Gastrointestinal (GI) tract: Predominantly anaerobic.
- Vagina: Comparatively acidic.
- Skin: Exposed to variable conditions like humidity, salinity, and temperature.
Skin Flora
- Common gram-positive cocci and bacilli inhabit the skin.
- Resident flora can reside in any layer of the skin i.e. epidermis, dermis, or subcutaneous layer.
- The skin has transient flora from environment; they are removed from being washed off, dry skin, an acidic pH due to sweat and oils.
- Examples include Staphylococcus epidermidis, and yeasts/fungi.
- Transient flora examples include Micrococcus and Bacillus species.
- Staphylococcus species, while typically harmless, can cause bloodstream infections if the skin is penetrated.
Eye Flora (Conjunctiva)
- The conjunctival sac of the eye hosts common gram-positive cocci and bacilli, and gram-negative cocci.
- Tears help control bacterial populations.
- Flora include Staphylococcus epidermidis, Staphylococcus aureus, Corynebacterium, and Streptococcus pneumoniae.
- Corynebacterium xerosis is frequently present.
- Marie species, non-hemolytic Streptococci examples of flora present.
Mouth and Nose Flora
- The mouth and nose contain diverse aerobic and anaerobic microbes.
- Common microbes include Corynebacterium species.
- Pneumonia is often preceded by a viral respiratory infection, predisposing individuals to Streptococcus pneumoniae infection.
- The mouth contains bacteria such as Lactobacilli, Staphylococcus, and Streptococcus species.
- Streptococcus mutans contributes to dental plaque and tooth decay.
- Post-dental surgery, there is a risk of bloodstream infections leading to endocarditis due to poor dental hygiene.
Intestinal Tract Flora
- The adult stomach has relatively few microorganisms due to gastric enzymes.
- The ileum has a high microbial density, nearly 10^11 per gram of contents.
- About 20% of fecal mass consists of microbes, primarily anaerobic.
- Common microbes include gram-positive cocci and gram-negative bacilli.
- The large intestine acts as a fermenting vessel.
- Primarily anaerobic gram-negative, non-spore-forming bacteria are present.
- Some Gram-positive, spore-forming, and facultative anaerobes such as E. coli exist.
- Diet influences gut flora composition; meat-rich diets cause more proteolytic bacteria, vegetarian diets cause more lactobacilli.
Vagina Flora
- Lactobacillus species are abundant in the adult vagina i.e. Lactobacillus acidophilus.
- A low pH maintains protective flora and prevents overgrowth of species like Candida albicans.
- Bacterial vaginosis (BV) involves the replacement of protective lactobacilli by harmful species like Gardnerella vaginalis.
- The genetics tract/vaginal tract has mucus and a large surface area, enabling the presence of larger quantities of microflora which allows it to be weakly acidic with polysaccharides i.e. glycogen
- Glycogen is fermented to produce lactic acid so as to keep the vaginal region acidic.
Urinary Tract Flora
- The epithelial lining and urethra are colonized by gram-negative, facultative aerobic cocci, and bacilli.
- Examples include Staphylococcus epidermidis, Enterococcus faecalis, and Corynebacterium species.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
