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1.22.5.14 - Non-Respiratory Lung Function - Coggle Diagram
1.22.5.14 - Non-Respiratory Lung Function
gases driving ventilation
carbon dioxide
more significant
oxygen
nerve supplies
carotid bodies
glossopharyngeal nerve
diaphragm
phrenic nerve
aortic bodies
vagus nerve
intercostal muscles
intercostal nerves
caudal to each rib
peripheral chemoreceptors
changed to blood oxygen concentration
non-respiratory functions of the lungs
heat exchanger
metabolism
immunological and mechanical defence
substrate synthesis
blood reservoir and filter
substrate modification
clearing inhaled particles
particle is wafted by cilia
particle is trapped by mucus
particle is swallowed
particle is destroyed
particle is inhaled
metered inhalers
drug is present in a compact aerosol
delivered through a metering valve
during inspiration
inhalation of liquid drugs
small aerosol particles
high air flow generated across the liquid
liquid can be inhaled
cellular and neurological mechanisms that cause bronchoconstriction in response to an allergy
brochoconstriction is the narrowing of the airways in the lungs
air flow in air passages can get restricted in three ways
spasmodic state of the smooth muscles
inflammation in the middle layers of the bronchi and bronchioles
excessive production of mucus
bronchial spasm is due to activation of parasympathetic nervous system
parasympathetic fibres release acetylcholine causing smooth muscle constriction
muscarinic receptors on smooth muscles
activation of muscarininc receptors activate a G protein
muscle contraction will cause the diameter of the bronchus to decrease and increase resistance to air flow
neurotransmitters and receptors that result in constriction and dilation
constriction
acetylcholine activates muscarinic receptors
dilation
fight/flight, beta adrenergic
receptor agonist
beta adrenergic receptors
receptor antagonist
muscarinic receptors
inflammation
casues bronchoconstriction
mast cells infiltrate the lungs
release of mediators that augment the inflammatory response
can result in epithelial damage and remodelling of the airway
blood reservoir and filter
holds ~ 20% of the blood volume, acts as a particulate filter for blood-borne particles
immunological and mechanical defence
secretory IgA, macrophages, mucociliary escalator, mucous lining airways, cough and sneeze reflexes
heat exchanger
acts as a source for considerable heat exchange and results in the insensible loss of water, especially for neonates
substrate modification/activation
activation
angiotensin I → angiotensin II
inactivation
bradykinin, serotonin, noradrenaline, acetylcholine etc. Unaffected- ADH, Adrenaline, Dopamine, Isoproterenol, etc.
substrate synthesis
surfactant, prostaglandins, histamine and heparin from mast cells, etc.
metabolism
uses 1-2% of the basal O2 consumption
clearance of inhaled particles
mucociliary escalator
ciliated epithelium
movements of cilia push it and anything in it such as inhaled particles or microorganisms up and out of the throat which get swallowed or removed thrgouh the mouth
advantages of inhaled therapy
In feline asthma which is a
long-term inflammatory disease that requires frequent or life-long therapy with glucocorticoids, in order to avoid systemic side effects, inhaled medications are very appealing
In horses aerosol preparations reduce systemic levels and side-effects, but can be cumbersome to deliver, as obligate nose-breather, horses cannot bypass delivery systems by mouth-breathing. Delivery systems are improving so that increased concentrations of drug reach the peripheral airways.
Inhaled therapy directly channels medication into the respiratory tract. In contrast, some systemic medications fail to adequately reach the source of infection or inflammation, particularly in patients with excessive mucus or established infection in the airway lumen