8. RESPIRATORY SYSTEM

Question 1

gas exhange in lungs because pO2 is higher in

Answer 1

alveolar air that in venous blood that reaches lungs > O2 will diffuse from alveolar air to blood

Question 2

pCO2 is higher in

Answer 2

blood > diffusion to alveoli

Question 3

at high altitudes O2 uptake is reduced

Answer 3

due low pO2 inhaled air

Question 4

transport of O2 in blood

Answer 4

98,5% bound to hemoglobin
>rest dissolved in plasma

Question 5

binding of O2 to hemoglobin

Answer 5

1 hemoglobin molecule can transport 4 O2 molecules

Question 6

when all iron atoms in all hemoglobin molecules in blood have bound O2

Answer 6

hemoglobin saturation is 100%
>ocyhemoglobin and deoxyhemoglobin
> saturation is also influenced by pO2

Question 7

O2 consumption per unit body mass is greater in small animals than in large ones > in small animals

Answer 7

-high density of capillaries
-low affinity of hemoglobin for O2

Question 8

respiratory tract dfence mechanisms

Answer 8

-coughing
-sneezing
-production of secretion, change in viscosity of secretion

Question 9

cough 1 protective reflex > role:

Answer 9

to remove secretions and foreign particles from respiratory tract
> coughing is also triggered by irritation of MM due to inflammation, secretions and foreign particles

Question 10

cough 2: cough receptors

Answer 10

in MM of resp.tract > mainly at back of throat, in throat, trachea, bronchi, as well as pleural mucosa

Question 11

cough 2: signals from receptors are carried through

Answer 11

vagus nerve to cough centre

Question 12

cough centre

Answer 12

in medulla oblongata and hypothalamus > controlled by cerebral cortex

Question 13

cough 2 : as result of reflex irritation-signal is initially carried to

Answer 13

cough center and thereafter from centre to muscles of respiration through motor nerve fibers

Question 14

types of cough

Answer 14

-productive cough; protective reaction-resp.tract is cleared of secretions
-non-productive cough-produced irritation in resp.tract causes decreased blood flow and disorders of resp.system > pressure in chest may increase, blood flow will accumulate in brain > pain and distress to animal

Question 15

cough suppression

Answer 15

1. direct suppression of cough centre
2. reduction of irritation of inflamed MM of resp.tract

Question 16

substances suppressing cough centre, opioids

Answer 16

-codeine,hydrocodone-opium alkaloids, part of narcotic analgesic group
-butorphanol-narcotic analgesic: also used cough centre suppressant in dogs

Question 17

suppression of cough centre in

Answer 17

medulla oblongata , indication is dry, non-productive cough

Question 18

codeine is partially metabolized in organism into

Answer 18

morphine
>effect of codeine itseld on CNS is substantially weaker than morphine

Question 19

substances suppressing cough centre, non-opioids

Answer 19

1. dextromethorphan-part narcotic analgesic group.non-opioid nature
   >no analgesic or sedative effect
   -causes only depression of CNS in large doses
   > effect on cough centre weaker than opioids
   >often used together with antihistamines, mucolytic drugs or bronchodilators
2. diphenhydramine-antihistamine > cough centre suppressant effect unclear, use cough suppressant

Question 20

expectorants (mucolytics) substances aiding in clearance of

Answer 20

phlegm from airways, mucolytic drugs
> ease excretion of secretions and inflammatory exudate from resp. tract
> incr, motility of ciliated columnar epithelium in bronchial region - thinning secretions, irritating bronchial MM > increase production of thin secretions

Question 21

expectorants (mucolytics) bromhexine: it makes

Answer 21

secretions thinner
> incr.permeability of alveolar - capillary barrier > ex. ABs can easier penetrate bronchial secretions

Question 22

acetylcysteine

Answer 22

-mucolytic
-treat paracetamol poisoning dogs, cats
-breaks down disuphide bonds of mucoproteins > sputum becomes thinner
>binds paracetamol metabolites into conjugates
-irritate bronchial MM > bronchial contraction
>not asthmatics!

Question 23

dembrexine makes

Answer 23

secretions thinner
-horses prep for oral use
not humans

Question 24

guaifenesin

Answer 24

-mucolytic agent
-horses prep for oral route

Question 25

bronchodilator agents (4)

Answer 25

1. beta (2) adrenomimetics
   2.antihistamines
2. antimuscarinic agents
   4- methylxanthines

Question 26

beta-adrenomimetics (adrenergic agonists)
….-use cautiously for widening bronchi as there are cardiovascular side effects
….-non selective beta agonists
….-selective beta2-agonists used in small animals
…..-selective beta2-agonist, used in horse and cattle

Answer 26

-adrenaline
-isoprenaline, ephedrine
-terbutaline,salbutamol
-clenbuterol

Question 27

terbutaline produces beta2-receptor-relaxation in

Answer 27

bronchial, vascular and uterine tissues
-used with care: pre-existing cardiac disease, diabetes, hypertension, hyperthyroidism
>salbutamol similar

Question 28

clenbuterol for treatment of

Answer 28

RAO

Question 29

antimuscarinis agents :
….in addition to widening of bronchi>large number of side effects exist (tachycardia, decrease GIT motility, urinary tract muscle tone )

Answer 29

-atropine
only used life-threatining bronchospasm

Question 30

…. antimuscarinic bronchodilators, spasmolytics in small animals, less side - effects

Answer 30

glycopyrrolate, propantheline

Question 31

methylxanthines: theophylline, euphyllin, aminophylline, theobromine

Answer 31

> relax smooth muscle of bronchi
increase activity of diaphragm
increase cardiac contractility, activity of CNS and diuresis
overdose leads tachycardia, shortness of breath and cramps
effects of theophylline and beta-blockers can be antagonized if administered together
theophylline incr. arrhythmias induced by adrenergic agonists and halothane
theophylline incr, seizures of ketamine

Question 32

other means of treatments :
-…used in bacterial infections of resp.tract
-…-in case of fever and inflammation
-…-in case of asthma, chronic non-infectious inflammatory diseases

Answer 32

-antibiotics
-NSAIDs
-glycocorticosteroids

Question 33

respiratory system stimulants; doxapram

Answer 33

-CNS stimulant
-used stimulate breathing during and after anaesthesia in dogs, cats and horses
-occurs via aortic and carotid sinus chemoreceptors
-contraindicated in case of asthma, pulmonary embolism, pulmonary edema and collapsed lung
> side effects incr. BP and cramping

Question 34

heptaminol+diprophyllin > supportive treatment in case of

Answer 34

acute cardiovascular and/or respiratory insufficiency
>heptaminol-cardiovascular analeptic, effect related to peripheral release of norepinephrine -incr. blood flow in aorta and coronary arteries
>diprophyllin-bronchodilator

Question 35

asthma 1: bronchoconstriction + inflammation in resp.tract > release of

Answer 35

inflammatory mediators triggers asthma attack
> infl.process trigger permeability of epithelial layer of MM with regard to inflammatory mediators (histamine, cholinergic stimulants)

Question 36

asthma 2: more permeable epithelial layer of MM enhances mediators reaching

Answer 36

nerve endings located in mucosa, cholinergic bronchoconstriction occurs
> vascular pempeability of BV and production of mucus also increase
> MM sustains damage due to inflammation and MM become extremely sensitive to mediators

Question 37

treatment of asthma: complex, widening of

Answer 37

bronchi + treatment of inflammation (NSAIDs, glycocorticosteroids, antibiotics) + mucolytic drugs + antihistamines

Question 38

emphysema: narrowing of

Answer 38

airways, lead to increased resistance of airflow
> expiration is primarily affected > bc. distention of airways is more difficult >increased flow resistance: elevated pressure in lungs
>total area available for diffusion is reduced
>severe deficiency of O2 in tissues

Question 39

emphysema leads to increased

Answer 39

CO2 supply in body fluids, causing respiratory acidosis

Question 40

treatment of emphysema

Answer 40

-bronchodilators
-corticosteroids
-NSAIDs