Exam 1

Question 1

What are the steps involved in bacterial infection?

Answer 1

1. Bacteria attach to host tissue
2. Bacteria invade tissue
3. Bacteria colonize the tissue
4. Colonization/replication cause damage to the tissue
5. Bacteria exit the host
6. Transmission to new host

Question 2

How does bacteria colonize the tissue?

Answer 2

Establish an infection
Creates proper conditions for replication
Hide from or fight host immune system

Question 3

What are the first line of defenses?

Answer 3

Skin

Mucosa

Question 4

What are the innate immune system defenses?

Answer 4

Inflammation
Complement
Phagocytes
Neutrophil extracellular traps
Natural killer cells
Apoptosis

Question 5

What are the adaptive immune system defenses?

Answer 5

Antibodies
CTLs
Activation of macrophages
Memory

Question 6

Examples of simple squamous epithelium layer?

Answer 6

Mouth

Lungs

Question 7

Example of simple cuboidal epithelium layer?

Answer 7

Kidney

Question 8

Examples of stratified squamous epithelium layer?

Answer 8

Skin

Vaginal tract

Question 9

Examples of simple columnar epithelium layer?

Answer 9

Intestinal tract

Question 10

Example of ciliated columnar epithelium layer?

Answer 10

Upper respiratory tract

Question 11

What exists on ciliated columnar epithelium layer that does not exist on other types of skin?

Answer 11

Mucus with goblet cells

Cilia

Question 12

What are tight junctions?

Answer 12

Connection between epithelial cells that prevents bacteria from moving between them. Combined with protein called occludin

Question 13

What can WT bacteria do to tight junctions?

Answer 13

Fragment the occludin to separate tight junctions

Question 14

Why do endothelial cells not have tight junctions?

Answer 14

To allow cells of the immune system to freely move across the internal surfaces.
* bacteria can easily cross the endothelium

Question 15

What are the defenses of the skin and what does each defense do against bacteria?

Answer 15

Dry, acidic environment: prevents growth of many bacteria
Dead, keratinized cells: hard to degrade, and dead cells discourage colonization
Sloughing of surface cells: removes bacteria that adhere
Toxic lipids, lysozyme: protects hair follicles, sweat glands, & sebaceous glands
Normal microbiota: competes with pathogens for nutrients/colonization sites
Underlying immune cells: combat bacteria that manage to reach the dermis and tissue below

Question 16

What are the mechanisms of resistance due to lysozyme?

Answer 16

Gram negative: outer membrane
Capsule
Proteases

Question 17

What are the characteristics of antimicrobial peptides?

Answer 17

Small peptide
Many have helical structures
Positively charge region
Hydrophobic region

Question 18

What are possible resistances to antimicrobial peptides?

Answer 18

Production of peptidase
Capsule
Incorporation of D-alanine into teichoic acids
Incorporatio nof D-lysine into phosphatidylglycerol
Incorporation of aminoarabinose and additional fatty acids into lipid A

Question 19

What are the benefits of normal microbiota?

Answer 19

Occupy surfaces so pathogenic bacteria can’t colonize them
Competes with incoming pathogens fro essential nutrients
Some produce bactericidal compounds (pore-forming toxins, growth inhibitors)
In GI tract: provide metabolic pathways beneficial to host (synthesize vitamins & other nutrients)
Play role in development of immune tissue (teaching role)

Question 20

What are the defenses of the eye?

Answer 20

Tears (washing action & antibacterial substances)

Question 21

What are the defenses of the airway entrance?

Answer 21

Mucus traps

Ciliated epithelial cells (propel bacterium-laden mucin blobs out of airway)

Question 22

What are the defenses of the stomach?

Answer 22

Acidic environment

Question 23

What are the defenses of the small intestine?

Answer 23

Rapid flow of contents

Sloughing of epithelial cells

Question 24

What are the defenses of the colon?

Answer 24

Resident microbiota
Sloughing of epithelial cells
Flow of contents

Question 25

What are the defenses of the vaginal tract?

Answer 25

Resident microbiota
Sloughing of epithelial cells
Flow of vaginal fluid

Question 26

What are the defenses of the bladder?

Answer 26

Sphincter keeps bacteria out of urethra

Flushing action of urine washes bacteria out of bladder

Question 27

What are the consequences of venous catheters?

Answer 27

Biofilm formation on catheter

Movement of bacteria into bloodstream

Question 28

What are the consequences of burns?

Answer 28

Infection of burned tissue (bacteria may move into underlying tissue & blood)

Question 29

What are the consequences of damage to cornea caused by contact lenses?

Answer 29

Infection of cornea

Question 30

What are the consequences of a respirator?

Answer 30

Allows bacteria to bypass defenses of upper airway

Question 31

What are the consequences of perforation of the intestinal mucosa during surgery or other abdominal trauma?

Answer 31

Release of bacteria into otherwise sterile tissue and blood

Question 32

What are the consequences of buffering of stomach acid?

Answer 32

Bacteria that cause intestinal infections are more likely to gain access to small intestine

Question 33

What are the consequences of indwelling urinary catheters?

Answer 33

Constantly drains bladder, eliminating washing action of urine
Keeps sphincter open