Host-microbes: the human body

Question 1

What is the skin composed of?

Answer 1

• epidermis, dermis and subcutaneous tissue

Question 2

What glands are associated with the skin

Answer 2

• eccrine
• apocrine
• sebaceous

Question 3

What is the condition of the skin

Answer 3

• dry, lysozyme (beta 1-4 linkage attacks cell wall), lack nutrition, UV exposure

Question 4

What happens when pathogens reach glands?

Answer 4

• environment is more favourable

Question 5

What are eccrine glands? What are they for and where are they found?

Answer 5

• sweat glands for body cooling
• palms, soles, finger pads

Question 6

What are apocrine glands? where are they?

Answer 6

• smell
• moist, underarms, genitals
• not functional till puberty

Question 7

What are sebaceous glands?

Answer 7

• hair follicles

Question 8

What happens if a pathogen reaches the sebaceous gland?

Answer 8

• reaches bloodstream and has access to everything in body if bloodstream isn’t sterile
• aerobic and anaerobic

Question 9

normal skin microbiota are _____ or _____ organisms primarily gram-_____.

Answer 9

• resident or transient
• positive

Question 10

What do gram + have that gram neg don’t? what does this help with?

Answer 10

• thicker peptidoglycan
• secures moisture

Question 11

give 4 examples of skin microorganisms

Answer 11

• staph spp
• strep spp
• propionibacterium acnes
• acinetobacter spp

Question 12

What affects the nature and extent of normal microbiota?

Answer 12

• weather, age, hygiene

Question 13

Where are microbiota found in the oral cavity?

Answer 13

• teeth and tongue

Question 14

Saliva is a source of certain ____ and _____ substances

Answer 14

• nutrients
• antibacterial

Question 15

Explain the steps in plaque/biofilm formation

Answer 15

• thin organic film from saliva glycoproteins
• colonization of species of strep
• formation of plaque as biofilm thickens
• growth of other microorganisms (spirochetes - filamentous bacteria)

Question 16

What happens if plaque accumulates?

Answer 16

dental caries (ex. lactic-acid producing bacteria)

Question 17

What do bacteria attach to in the oral cavity?

Answer 17

• chemical layer and withstand conditions of lysozyme

Question 18

Where are bacteria most protected in the oral cavity?

Answer 18

• under gums, access to bloodstream

Question 19

What does the GI tract consist of?

Answer 19

• stomach, small intestine, large intestine

Question 20

What is the pH of stomach acid?

Answer 20

• 2: kills bacteria

Question 21

What is the pH of the stomach wall?

Answer 21

• 4: special enzyme allows bacteria to burrow

Question 22

What causes ulcers?

Answer 22

• helicobacter burrows in stomach walls

Question 23

State and describe 2 areas of the human body where you may expect microbial occupancy. Which conditions favour this growth and why?

Answer 23

• The highest numbers of microorganisms are found in the colon where the pH is neutral. The colon also has fermentative bacteria which produce lactic acid and gas production allowing for a larger space for bacterial growth.
  The oral cavity is another location that microorganisms may be found. This is because saliva is a source of certain nutrients, and the environment is moist allowing for growth.

Question 24

Where are the highest numbers of microorganisms found? What is it considered to be?

Answer 24

• colon
• “specialized fermentation vessel”

Question 25

What kind of bacteria are found in the colon?

Answer 25

- strict and obligate anaerobes - some facultative anaerobes

Question 26

What plays a significant role in determining the normal population of the GI tract?

Answer 26

- diet

Question 27

What allows for the survival of strict/obligate anaerobes?

Answer 27

- E. coli attacks O2 as soon as it is available

Question 28

Why does colon have fermentative bacteria? what is produced?

Answer 28

- larger space - lactic acid and gas production

Question 29

Fecal matter is ____ bacteria and ____ concentrated, digested material

Answer 29

- 1/3 - 2/3

Question 30

What causes intestinal gas

Answer 30

- activity of fermentative and methanogenic microorganisms in addition to swallowed air

Question 31

What does the upper respiratory tract consist of?

Answer 31

- nasopharynx, oral cavity, throat

Question 32

What does the lower respiratory tract consist of?

Answer 32

- trachea, bronchi, lungs

Question 33

Where does respiratory tract become sterile?

Answer 33

- below trachea/larynx dividing line

Question 34

in the upper respiratory tract, what are a majority of bacteria associated with?

Answer 34

- mucous membranes in the nasal passages

Question 35

Give examples of bacteria found in the upper respiratory tract

Answer 35

- staph, strep, diphtheroid, gram-neg cocci

Question 36

What happens if lower respiratory tract is not sterile?

Answer 36

- organ infection/inflammation

Question 37

Why is mucosal lining important?

Answer 37

- protective barrier that bac attach to - keep bac from reaching bloodstream

Question 38

What does septicemia mean?

Answer 38

- infection of bloodstream

Question 39

What is the lower respiratory mechanical defence?

Answer 39

- cilia

Question 40

What happens when cilial elevator is compromised?

Answer 40

- secondary infection

Question 41

What does smoking do to cilia? What illness is specific to ciliated cells?

Answer 41

- burns them off - whooping cough

Question 42

what kind of bacteria line the urethra?

Answer 42

- facultative aerobic gram-negative rods - may be opportunistic

Question 43

the vaginal tract is ____ ____ and contains lactobacillus acidophilus

Answer 43

- weakly acidic

Question 44

What causes environmental change in the vagina?

Answer 44

- hormone stages and cycles

Question 45

What causes a yeast infection?

Answer 45

- bacterial balance upset and don't hold to lining