Respiratory Tract Infections

Question 1

Features of the respiratory system that help rid it of pathogens

Answer 1

1. mucociliary lining of the nasal cavity
2. change of direction of the airway from the sinues to the pharynx
3. ciliary elevator
4. normal flora competition
5. alveolar macrophage eliminates microorganisms in the lungs

Question 2

2 main obstacles pathogens must overcome to initiate infection

Answer 2

1. avoid/survive mucus layers of upper respiratory tract

2. must avoid phagocytosis to be able to survive and/or multiply in the phagocyte cell

Question 3

Turbinate bones

Answer 3

covered with mucus that collects particles not filtered by nasal hairs. They cause the air to swirl as it passes over causing a swirling pattern that forces the pathogens to make contact with the mucus.

Question 4

mucociliary escalator

Answer 4

covers the bronchi, bronchioles and nose

Goblet cells produce mucus while cilia are always beating, pushing the mucus up and out of the throat

Question 5

What can be secreted as a defense?

Answer 5

secretory IgA
B cells under the epithelial layer secrete antibody. The secretory chain allows it to pass and can neutralize a pathogen.

Question 6

Conditions that must be met for an infection to occur

Answer 6

1. Sufficient dose of microogransims inhaled
2. infectious particles must be airborne
3. airborne particles must be viable in the air
4. organism must land on susceptible tissue

Question 7

Viruses that can cause the common cold

Answer 7

Rhinovirus, Adenovirus, Coronovirus

Question 8

Sinusitis

Answer 8

secondary infection with bacteria

Question 9

Pharyngitis

Answer 9

viral and bacteria infections

S. pyogenes, C. diptheriae, Adenovirus

Question 10

Lower respiratory tract diseases (5)

Answer 10

1. bronchitis
2. bronchiolitis
3. influenza
4. pertussis
5. Pneuomia

Question 11

Bronchitis

Answer 11

viral infection

bacterial secondary infections possible

Question 12

Rhinitis

Answer 12

common cold

Question 13

Symptoms of rhinitis

Answer 13

Incubation period of 2-5 days
nasal stuffiness, sneezing, sore throat, low fever, headache, watery eyes
caused by cytopathic effect and immune response

Question 14

Spread of rhinitis

Answer 14

direct contact of contaminated surfaces, inhalation of infectious droplets

Question 15

When do symptoms of rhinitis reach their peak

Answer 15

2 to 5 days post infection

cells are regenerated by 14 days

Question 16

Adenovirus characteristics

Answer 16

nonenveloped
linear d.s. DNA
replicates in epithelial cells

Question 17

What does adenovirus commonly cause?

Answer 17

Pink eye (conjunctivitis)
Pharyngitis (red throat, enlarged tonsils, white nobs)

Question 18

Pharyngitis symptoms

Answer 18

fever, sore throat, edema, hyperermia of tonsils

Question 19

Symptoms of pharyngitis likely being caused by a virus

Answer 19

conjunctivitis, cough, hoarseness, inflammation of mucus membrane, diarrhea

Question 20

Signs of pharyngitis being caused by streptococcus pyogenes

Answer 20

High fever, severe swallowing pain, headache, vomittng, red tonsils, enlarged lymph nodes

Question 21

When is pharyngitis more common?

Answer 21

during the winter and spring

Question 22

Croup symptoms

Answer 22

fever of 100-102
shortness of breath
cold like symptoms early on
bark-like cough
severe can lead to nasal flaring, intercostal retractions, tachycardia

Question 23

Who is more susceptible to croup?

Answer 23

young children 6 months to 3 years
boys more likely than girls
occurs more in late fall and early winter

Question 24

RSV Characteristics

Answer 24

s.s. negative nonsegmented
enveloped
creates giant nucleated cells

Question 25

Influenza characteristics

Answer 25

ss negative segmented genome
enveloped
3 classes A, B, C

Question 26

How does influenza attach to host cells?

Answer 26

Hemagglutinin (16 types) helps the virus attach to the upper respiratory cells. After it replicates, neurominadase (9 types) cleaves the bond between galactose and sialic acid to leave the cell.

Question 27

How come we can’t get long lasting immunity?

Answer 27

Point mutations are always accumulating where the antibody would bind.

Question 28

Antigenic shift

Answer 28

occurs when major changes in antigens occur due to gene reassortment in influenza virus

Question 29

Antigenic drift

Answer 29

occurs when minor changes in antigens occur due to gene mutation in influenza virus

Question 30

Mumps characteristics

Answer 30

single stranded RNA
can form synctia
humans only host

Question 31

How does mumps spread and cause infection?

Answer 31

Spreads through respiratory droplets, Once it enters it goes systemic then goes back into glands and sets up massive inflammation.
It can incubate 2-3 weeks.

Question 32

Family of RSV

Answer 32

Paramyxoviridae

Question 33

Family of Influenza

Answer 33

Orthomyxoviridae

Question 34

Family of Adenovirus

Answer 34

Adenoviridae