DLA7(2)- Basics of RTI

Question 1

URT:

• (1) components
• (2) temperature
• (3) commensal flora
• (4) epithelium
• (5) additional cells
• (6) secreted Igs

Answer 1

1- nose to larynx
2- 33-35C
3- complex metastable ecosystem, ‘probiotic microflora’
4- ciliated pseudostratified columnar cells
5- mucus secreting cells
6- IgA

Question 2

LRT:

• (1) components
• (2) temperature
• (3) commensal flora
• (4) epithelium
• (5) additional cells
• (6) secreted Igs

Answer 2

1- trachea to alveoli
2- 37C
3- sterile, no flora
4- nonciliated epithelium
5- n/a
6- IgG, IgA

Question 3

_______ is necessary for microbes and particles to go from URT to LRT

Answer 3

<5 µm in size

Question 4

_______ is the ‘unofficial’ demarcation between URT and LRT

Answer 4

vocal cords

Question 5

describe the defensive structures and components of the respiratory tract

Answer 5

• nonspecific barriers: 2-10µm particles may or may not get trapped on the way to LRT, <2µm will reach LRT
• alveolar macrophages in LRT to mop up foreign particles

-Secretions: S-IgA, Lactoferrin (neutrophils, traps and sequesters Fe –> microbial death), Lysozyme (neutrophils, direct anti-microbial)

Question 6

what are the requirements from microbes in order to establish a respiratory infection

Answer 6

• by-pass barrier defenses & filtering systems
• contact with suitable receptor surface
• evasion of immune response

Question 7

Commensal flora in URT and LRT differ in people due to (1) and (2).

Commensal flora provide additional defenses from invading microbes by (3) and (4).

Answer 7

1- age (no anaerobe before teeth grow)
2- location

3- occupying receptors, blocking invading microbes from entry
4- secretion of anti-microbials (not super powerful)

Question 8

list the Major Viral Families involved in majority of respiratory infections

Answer 8

1) adenovirus
2) rhinovirus
3) coronavirus

HPIV, RSV, Influenza viruses, (non-polio picornaviruses are ‘emerging’)

Question 9

adenovirus is a (small/large) (non-/enveloped) (+/-) sense (ss/ds)(RNA/DNA) virus

Answer 9

small/medium non-enveloped (+/-) sense dsDNA (linear) virus

Question 10

rhinovirus is a (small/large) (non-/enveloped) (+/-) sense (ss/ds)(RNA/DNA) virus

Answer 10

small non-enveloped (+) sense ssRNA virus

Question 11

coronavirus is a (small/large) (non-/enveloped) (+/-) sense (ss/ds)(RNA/DNA) virus

Answer 11

large enveloped (+) sense ssRNA virus

Question 12

describe the significance for teeth and normal oral flora

Answer 12

when teeth grow in, then anaerobic microbes will grow and be present in normal oral flora