Respiratory System Exam 1 Flashcards
Functions of respiratory system
-draw air into lungs, supplying oxygen
-transfer oxygen from air to blood
-acid/base regulation
-humidification of inspired air
-thermoregulation
-defense against environmental contaminants (ciliated mucosa sweep away particles)
-provide sensory input via olfactory cells
-communication
-increasing abdominal pressure
Arytenoid cartilage
abducts to open entry to the trachea
What is the limiting factor in competing animals?
always the respiratory system
everything else can be improved
Obligate nasal breathers
always breath through the nose, not both the nose and the mouth
What does cartilage look like when it is strong?
serrated edges and holds down the soft palate
Asynchronism
when the arytenoids close off sync from each other
Hemiplegia
-roaring
-when one arytenoid side does not open
-not enough air can get into the lungs, cannot perform as well
What is a fix for dorsal displacement of the soft palate?
tongue ties
Gas exchange
bringing gas and blood to the alveolis
-transports O2 and CO2 between environment and tissues
What is the tracheobronchial tree line with?
secretory ciliated epithelium
Mucociliary system
cells that produce mucus
What surrounds the airways from trachea to alveolar ducts?
smooth muscle - contracts to cause constriction and decrease surface area
Bronchoconstriction is a response to what?
adverse stimulus: cold air, allergies, infection, polen, asthma, etc.
Etiology
what a virus is
Influenza types
A, B, and C
What type of influenza do horses get?
only A
Which influenza type is more severe?
A
The influenza bacteria is ______
enveloped - derived in lipid envelope
What is embedded on the envelopes
500 spikes
-Hemagglutinin (H)
-Neuranimidase (N)
What is responsible for fusion between virus and host cell?
hemagglutinin
What is the major target of the host immune response?
hemagglutinin
What facilitates mobility of virus and assists in release of the budding viruses?
Neuranimidase
How many H subtypes are there?
16
How many N subtypes are there?
9
Where were all H and N subtypes acquired?
from aquatic birds
What H/N formula do horses get?
H7N7 and H3N8
H7N7
type of influenza horses get
-hasn’t been detected since the late 1970s
-not included in vaccines
H3N8
-newer version
-circulates around the world
Where can H3N8 not be found?
austrailia, new zealand, iceland
What are the two distinct lineages of H3N8?
american and european
Incubation period
time the animal comes in contact with virus to time they begin showing symptoms
How long is the influenza incubation period?
24-48 hrs.
Epidemiology
how the disease is maintained/spread
What age is the highest influenza incidence in?
2-3 year olds
Why is influenza rate highest in 2-3 year olds?
-they move around (causes stress which lowers immunity and increases cortisol)
-they do not get as much turnout time
-stress from starting to compete and traveling to compete
What are outbreaks caused by?
the large gathering of horses at racetracks, shows, sales, and airplanes
What can a secondary bacterial infection lead to ?
pneumonia
Morbidity
of the animals that got in contact with the virus, how many get sick
Mortality
of the horses that got sick, how many died
Morbidity of influenza
60-90%
Mortality of influenza
1%
How long can horses be immune to influenza after natural infection?
up to 32 weeks, immunity declining after
What does vaccination do?
-reduces the frequency of outbreaks
-reduces the frequency of clinical signs
-reduces recovery time
How long is influenza recovery?
for every 1 day a horse has a fever they need 1 week of rest
How long does it take for the epithelial cells to regrow after symptoms stop?
3 weeks
How is influenza spread?
-direct contact
-droplets
-airborne
-maybe fomites
How long do horses shed virus for after infection?
7 days
Pathogensis
once the virus is contracted, what happens to the body
What is the target of influenza?
airway epithelial cells
What does virus replication lead to?
-cell death
-desquamation
-denudation
Clinical signs of influenza
-fever = 106 degrees
-nasal discharge
-cough
-anorexia
-weight loss
How long do clinical signs last?
2 weeks, cough stays longer
Treatment for influenza
-rest in a non-stressful environment
-fluids
-NSAIDs
-antivirals (may cause CNS adverse effects or rapid drug resistance
How long before horses with influenza can return to activity?
50-100 days after the disease cleared
Modified live vaccines
-intranasal, cold adapted
-6-12 months protection
Recombinant vaccines
-canary pox vector
-excellent performance against the most recent viral lineages
When should a horse first be vaccinated?
as a foal, greater than 6 months of age
When should broodmares be vaccinated?
2-6 weeks pre-partum (~1 month before foaling)
How often should we vaccinate?
every 6 months in high-risk populations
