Respiratory Medicine [10&11] Flashcards
3 main reasons for respiratory issues
- Ventilation - airway obstruction
- Perfusion - circulation problems
- Diffusion - thick scar tissue
What is affected by fibrosis (scarring)
Interstitium - tissue between air sacs
What are type 1 cells in the lungs for
Gas exchange - thin surface
What are type 2 cells in the lungs for
Secreting surfactant
- resist surface tension so alveoli don’t collapse
What are fibroblasts in the lungs for
They lay down collagen & elastin in fibrosis
What is the perinuclear zone in type 1 cells
Clustered organelles & nucleus
Synthesises products that diffuse into cytoplasmic flaps
Can type 1 cells regenerate
No
The have no mitosis potential
Can type 2 cells regenerate
Yes
They can replace type 1 cells after injury
What to macrophages in the lungs target
Particulate material that escapes tracheobronchial filters
How do macrophages leave the lungs
Migrate to nearest bronchiole & exit via mucociliary escalator
Or pass into interstitium & exit via blood or lymph
What mechanisms lead to bronchoconstriction
Inflammation
Obstruction
Mucus overproduction
What happens to extra-cellular matrix in lung disease
Excessive ECM accumulation and reduced degradation of ECM
- scar tissue
3 types of bronchodilator
Beta 2 agonist
Anticholinergic
Theophylline
2 diseases that require bronchodilators
Asthma
COPD
Bronchoconstriction reflex
Ach binds M3 Muscarinic receptors in muscle
Intracellular calcium release
Contraction
What are anticholinergics
Competitive antagonists of Muscarinic ach receptors
Example of short acting cholinergic
Ipratropium bromide
Example of long acting anticholinergic
Tiotropium bromide
Why are anticholinergics not helpful in asthma
They only reduced vagal my mediated bronchoconstriction
- not inflammatory mediated constriction
Side effects of anticholinergics
Dry mouth
Urinary retention
Constipation
How much inhaled ipratopium is absorbed
1-2%
How is ipratropium eliminated
Unchanged in faeces or urine
What could form a precipitate with ipratropium bromide
Eromolyn sodium
Mechanism of beta 2 agonists
Bind G protein coupled beta 2 receptors
Activate adenylyl cyclase
Catalyses formation of cAMP
Activates PKA
Phosphorylates protein targets leading to muscle relaxation
Beta 2 agonists - Pathways downstream of PKA lead to
Decreased Ca2+
- sliding filament theory -> contraction needs high Ca2+
2 examples of short acting beta 2 agonists
Salbutamol
Terbutaline
2 examples of long acting beta 2 agonists
Salmeterol
Formoterol
Side effects of beta 2 agonists
Non-selective ones have non-specificity problems
Tachycardia
Tremor
When is salbutamol used
Premature labour to prevent uterine muscle contraction
What do theophylline’s do
Inhibit phosphodiesterase which breaks down camp
- promotes lowering of Ca2+ levels
- bronchodilation
What causes decreased clearance of theophyllines
Heart failure
Viral infections
What causes increased clearance of theophyllines
Smoking
Alcohol
What do glucocorticosteroids do
Downregulate proinflammatory cytokines
Example of oral steroid
Prednisolone
Example of inhaled steroid & side effect
Beclomerhasone
Can cause oral candidiasis
What happened when histamine binds the H1 receptor
Increased calcium
Contraction
What happens when histamine binds the H2 receptor
Increased camp
Gastric acid secretion
Vasodilation
What happens when histamine binds the H3 receptor
Decreased camp
Decreased histamine release
Example of an anti histamine
Loratidine for allergic inflammation
Which generation of histamines can cross the blood brain barrier
First generation
Which generation of histamines is non-sedating
Second generation
What is an expectorant
Hypertonic saline
Increases secretion and hydration of mucus
What is a mucoregulator
Anticholinergic agents
Decreases secretion volume
What is a mucolytic
N-acetylcysteine
Breaks disulphide bonds linking mucin polymers
What is a mucokinetic
Bronchodilator
Improves cough clearance
What is the cough reflex
Vocal chords close
Abdominals contract & intercostals brace
Pressure in thorax
Vocal chords open
Expel air
What drug class suppresses cough
Antitussive
2 examples of antitussives
Dextromethorphan
Codeine
What is IPF and how is it treated
Idiopathic pulmonary fibrosis
Treatments only reduce decline
3 IPF treatments
Perfinidone
Nintedamib
Simtuzumab
