Heaves (Cram Set)

Question 1

Difference between respiration of horses and other mammals?

Answer 1

Horses ? expiration is passive apart from last part, where they expire beyond their resting volume
Stores recoil energy used for next inspiration

Question 2

What part of equine anatomy means that horses are obligate nasal breathers?

Answer 2

Soft palate tightly adhered to epiglottis of larynx

Question 3

Arterial blood samples from horses?

Answer 3

Common carotid
Median
Lateral palmar digital

Question 4

Dangers with arterial blood sampling?

Answer 4

Haematomas common
Need thick needle to stab muscular walls
Hold pressure on afterwards
Damage to nerves

Question 5

Name for poor P(A?a) value?

Answer 5

Ventilation?perfusion mismatch

Question 6

What gives blue colour to hypoxic pony with heaves’ mucus membranes?

Answer 6

High levels of deoxygenated haemoglobin

Question 7

Where is the most likely place for collapse during inspiration?

Answer 7

Upper airways ? trachea, larynx, pharynx ? reduced by cartilage and muscle

Question 8

Where is the most likely place for damage during expiration?

Answer 8

Alveoli and bronchi ? reduced by surfactant and cartilage presence

Question 9

Function of surfactant?

Answer 9

Reduces surface tension and alveolar collapse

Made by type 2 alveolar cells

Question 10

Change in intrapleural pressure and total pulmonary resistance in horse with heaves?

Answer 10

High change between inspiration and expiration

High total pulmonary resistance

Question 11

No muscle in bronchioles and alveoli

Answer 11

fhd

Question 12

Cause of heave line?

Answer 12

Recruitment of abdominal muscles to assist with effort for breathing ?> hypertrophy of external abdominal oblique muscle

Question 13

Function of mast cells?

Answer 13

Degranulation and IgE for parasites
Recruitment of eosinophils
Anaphylaxis
Inflammation and wound healing

Question 14

Difference between mast cells and basophils?

Answer 14

Basophils blood

Question 15

Describe type I hypersensitivity

Answer 15

IgE mediated ? immediate?type ? allergic response to antigen/allergen

Question 16

Describe type III hypersensitivity

Answer 16

IgM or IgG ? accumulation of antibody?antigen complexes

Question 17

Histology of heaves bronchioles?

Answer 17

Hypertrophy
Thickened alveolar wall
Cell and liquid debris in lumen
Fibrosis

Question 18

Respiratory bronchioles

Answer 18

Mainly absent in ruminant, horse and pig

Question 19

Parts of mucociliary escalator?

Answer 19

Mucus
Pseudostratified ciliated columnar epithelium
Goblet cells

Question 20

How is the reflex for coughing sent to brain?

Answer 20

irritant receptors in pharynx, trachea, larynx via vagus nerve

Question 21

4 phases of cough?

Answer 21

Deep inspiration, glottis closes, deep expiration, glottis opens

Question 22

How does the parasympathetic NS have a role in heaves?

Answer 22

Causes smooth muscle contraction by inflammation mediators ? irritants cause release of ACh ? constriction

Question 23

Factors affecting diffusion rate across alveoli?

Answer 23

Diffusion distance
Concentration gradient
Surface area

Question 24

Finding out which is the allergen?

Answer 24

Test and remove
Check history
Skin and blood test
Test hay sample

Question 25

How does atropine block the parasympathetic innervation?

Answer 25

Inhibits Ach (cholinergic) muscarinic innervation ? reduces constriction and mucus secretion

Question 26

Repeated use of atropine?

Answer 26

``` Fixed and dilated pupils Urine retention in bladder Tachycardia Excitability Can cross BBB ? convulsions Dry oral mucosa ```

Question 27

Why not continued use of B2?agonists?

Answer 27

Doesn't rid of inflammation Tachycardia Tremors

Question 28

B2 adrenergic receptors

Answer 28

Smooth muscle dilation except for heart

Question 29

Corticosteroids?

Answer 29

Target inflammation

Question 30

Systemic versus inhalation

Answer 30

Systemic ? may lead to laminitis, affect other areas of body | Inhalation ? direct contact with area, difficult to acclimatise animal, may be coughed out