Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MBIO > Medical microbio: the human microbiome > Flashcards

Medical microbio: the human microbiome Flashcards

1
Q

Human microbiome

A

-the collection of all the microorganisms living in association with the human body (microflora, microbiota)
ex number of human cells in the human body.. etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

number of human cells in the human body

A

~10^13

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

number of microorganisms in the human body

A

~10^14

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

number of genes in the human genome

A

~20,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

number of genes in the microbiome

A

~20,000,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

colonization

A

begins immediately after birth

-diversity of species present varies greatly between individuals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where does the microbiota live?

A
  • every exposed area of the body is colonized by bacteria like skin and mucous membranes
  • internal tissues should be free of microbes: like blood, muscles, organs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are microbiota doing in the body?

A
  • most are harmless commensals
  • few contribute to disease
  • many contribute to health:
  • produce beneficial products
  • inhibit the growth of pathogens
    ex. lactobacillus acidophilus protects the female reproductive system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

microflora of the skin

A
  • different areas of the skin vary in chemical composition and moisture content
  • provides 3 different micro environments: dry skin, moist skin, and sebaceous skin
  • each with different microbial populations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

dry skin

A
  • (forearms, hands)
  • high numbers of betaproteobacteria
  • known from 16 rRNA genes
  • rarely cultured-no one really knows what they’re doing
  • second highest is corynebacteria
  • most are harmless commensals, but some may cause skin infections
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

corynebacterium diphtheria

A

example of dry skin bacteria

-can case non-healing ulcers of the skin- cutaneous diphtheria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

moist skin

A

(armpits, nostrils)

  • high numbers of corynebacteria and staphylococci
  • most are harmless commensals : staphylococcus epidermis -most frequently isolated from skin
  • some are important pathogens: ex. staphylococcus aureus - cause of boils, abscesses, wound infections
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

sebaceous skin

A

(oily skin around the nose, on the upper chest and back)

  • high numbers of propionibacteria
  • anaerobic actinobacteria that produce propionic acid as as end-product of fermentation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

propionibacterium acnes

A
  • sebaceous skin
  • lives in hair follicles and eats sebum- oil secreted by skin
  • overgrowth can trigger inflammation
  • inflammatory acne
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

microflora of the oral cavity

A

saliva has antimicrobial enzymes:

  • lysozyme
  • lactoperoxidase- catalyzes production of superoxide radicals O2-, oxidative damage to invading microbes
  • despite this, this mouth is home to a complex microbial community, including aerobes and anaerobes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Neisseria mucosa

A

microflora of the oral cavity
aerobic
lives on mucous membranes like the tongue

17
Q

Streptococcus mutans

A

microflora of the oral cavity
aerotolerant anaerobe
-produces sticky dextran slime layer that lets it stick to surfaces
*forms biofilms in crevices around the teeth
-produces lactic acid as an end-product of fermentation
-degrades tooth enamel
*dental carries (cavities)
-can lead to inflammation along the gum line: gingivitis

18
Q

microflora of the gastrointestinal tract

A

-the stomach
the small intestine
the large intestine

19
Q

Stomach

A

low pH and proteolytic enzymes make the stomach inhospitable to most microbes
-some bacteria do colonize in the stomach

20
Q

helicobacter pylori

A
  • microflora in stomach
  • colonizes surface of membrane, protected from stomach acids by mucous
  • has a number of virulence factors:
  • exotoxin-kills cells in the membrane
  • endotoxin- triggers inflammation
  • cause of stomach ulcers
  • treated with antibiotics-tetracycline
21
Q

the small intestine

A
  • area of rapidly changing pH

- as pH becomes more neutral, bacterial numbers increase

22
Q

Enterococcus

A
  • small intestine microflora
  • genus of Gram positive lactic acid bacteria
  • frequent cause of nosocomial infections (ex. blood infections)
  • develop antibiotic resistance readily (ex VRE)
  • spread resistance genes onto other gram positive bacteria
  • horizontal gene transfer
23
Q

The large intestine

A
  • pH is neutral, environment anoxic
  • enormous number of microbes ~10^11 cells/g of feces
  • mostly anaerobes and facultative aerobes
  • 16S rRNA gene sequences reveal that E. coli probably makes up
24
Q

E. coli

A
  • large intestine microflora
  • most cultured bacterium from feces
  • indicator of fecal contamination
  • most strains are non-pathogenic
  • may stimulate the immune system
  • produce vitamin K
25
Q

role of gut microorganisms in obesity

A
  1. studies compared normal mice with germ free mice:
    * germ free mice has 40% less body fat
  2. inoculated germ free mice with microbes from healthy mouse intestines
    * inoculated mice quickly gained weight
  3. compared the microbiomes of normal weight mice to genetically obese mice
    * genetically obese mice had few bacteroidetes, more firmicutes and way more methanogens
    - suggested that methanogens use up H2 which promotes bacterial fermentation
    - bacterial fermentation makes nutrients available to the host
26
Q

changing the microbiota of the large intestine can affect human health:

A

ex. oral antibiotics
- opportunistic pathogens can take over
- Antibiotic associated colitis

27
Q

antibiotic associated colitis

A
  • clostridium difficile grows
  • inflammation of the colon
    treatment: further antibiotics, probiotics, Transpoosition
28
Q

microflora of mucosal tissues

A

upper respiratory tract
lower respiratory tract
genitourinary tract
female reproductive tract

29
Q

upper respiratory tract

A
  • home to a variety of bacteria including staphylococci, streptococci, and corynebacteria
  • some people harbour pathogens among their normal microflora
  • carriers
    ex. staphlococcus aureus
30
Q

lower respiratory tract

A

no resident microflore

-mucous, lysozyme, ciliated cells, secretory IgA, phagocytes

31
Q

Genitourinary tract

A

upper urinary tract (kidneys, bladder)
*normally free of microorganisms
Urethra
*home to some gram negative bacteria
-some members of the normal microbiota can act as opportunistic pathogens when transferred to urinary tract
.e.coli is one of the most common causes of urinary tract infections

32
Q

female reproductive tract

A
  • lactobacillus acidophilus in the vagina produces lactic acid from glycogen
  • lowers pH and prevents growth of other microbes
  • if normal microbiota is disturbed (ex. lactobacilli killed by antibiotics): yeasts can grow and cause yeast infections

MBIO (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions