Amy's Asthma Flashcards
Why are inhaled foreign objects more likely to enter right lung?
It is more vertically orientated and wider than the left
Where are higher centres of breathing located?
Pons
What is the aim of asthma therapy?
Symptomatic relief
Which types of hypersensitivity are most important in asthma?
Type I and IV
Which vertebrae does the trachea extend over in the adult?
C6-T4
Where does cricothyroid membrane lie?
Below level of vocal chords
What factors does peak flow depend on?
Age, sex, height, pathologies
What is the mucociliary escalator?
Inhaled particles are trapped in the mucus of the respiratory tract and cels secrete an antibiotic fluid and then cilia beat to waft this fluid either upwards (in the case of trachea and bronchi) or downwards (in the case of nasal cavities) so the fluid containing pathogens is swallowed (and destroyed by stomach acid) or coughed out.
What is the arterial oxygen pressure below which cyanosis will generally appear?
7 kPa
What do the paranasal sinuses do?
Decrease relative weight of bones of the face, increase resonance of voice, provides a buffer against blows to the face, insulates eyes and dental roots from temperature fluctuations of nasal cavity, humidifies and heats inhaled air due to slow air turnover
How do glucocorticoids work?
Suppression of pro-inflammatory cytokine gene activation by sequestering nuclear transcription factors from gene production preventing infiltration and activation of inflammatory cells in the airways reducing mucosal oedema and improving airflow
Where does the oesophagus pass through the diaphragm and why?
Through the muscular portion of the diaphragm as it acts as a sphincter to prevent reflux of food
Name 5 extrinsic irritations which cause coughing.
- Large heart due to congestive heart failure compressing bronchi and recurrent laryngeal nerve
- Pericarditis
- Large lymph node due to Hodgkin’s disease
- Trauma where force is applied to lung, mediastinum or pericardium
- Diverticula of oesophagus pressing on trachea
What are the attachments of the sternocleidomastoid muscle?
Superiorly to mastoid process of skull, then to the clavicle then inferiorly to the sternum
Name two xanthines.
Theophylline, aminophylline
What percentage of the population have chronic illness or disability?
15%
What is the main mechanism of anti-cholinergics?
Block effects of acetylcholine released from parasympathetic efferents, blocking mucus oversecretion and SM contraction
What do afferent nerve fibres of the lung do and what are they?
Sense stretch, chemical environment (J-receptors) and noxious stimuli (irritant receptors) via the vagus nerve
Which type of hypersensitivity is antibody independent?
Type IV
Where are the chemoreceptors affecting breathing located?
Around the exit of cranial nerves IX and X
Where in the lung does pneumonia usually affect?
One lobe
What increases broncho-motor tone?
Parasympathetic vagal stimulation, inflammatory mediators and irritants
What do central chemoreceptors respond to?
PCO2 of blood
What is instantaneous breathlessness a sign of?
Pulmonary embolism or pneumothorax
What is atopy?
Hypersensitivity to allergens, allergy
What is infection of paranasal sinuses caused?
Sinusitis
What are the 4 paranasal sinuses and where are they found?
Frontal- frontal bone of forehead
Maxillary- cheekbones on either side of nose
Ethmoidal- above nasal cavity
Sphenoidal- behind the ethmoidal sinus
Name two inhaled glucocorticoids.
Fluticasone and beclomethasone
Name an anti-cholinergic drug used to treat asthma.
Ipratropium
Where does the left phrenic nerve run on its course to the diaphragm?
It enters the thoracic inlet anterior to scalenus anterior and anterior to lung root, running over the left border of the heart until finally piercing the muscular portion of the diaphragm
Where do chemical and stretch receptors feed in to to control breathing?
Medulla
How is visceral pain of the lung transmitted?
Sympathetic nerves T1-4
What is the primary role of the larynx?
As the sphincter of the airways
What are the opposing forces applied to the visceral and parietal pleura?
The elastic recoil of the lungs pulls the visceral pleura inward and the muscle tone of thoracic wall and diaphragm pulls the parietal pleura outward
What causes breathlessness in asthma?
Increased work of breathing
What recruits eosinophils in type IV hypersensitivity?
IL-4, IL-5, IL-13
Which cells are involved in the pathology of asthma?
Th2 cells and eosinophils
What generation are bronchioles (non-respiratory)?
13-16
Which immunoglobulin plays a major role in type I hypersensitivity?
IgE
Which chemoreceptors does low PO2 stimulate?
Peripheral chemoreceptors
What could indicate a tension pneumothorax or collapsed lung in one side?
The chest expanding differentially
What are the anaphylatoxins of complement?
C3a and C5a
Where does the right phrenic nerve run on its course to the diaphragm?
It enters the thoracic inlet anterior to scalenus anterior and anterior to lung root, running over the right border of the heart until finally piercing the central tendon of the diaphragm
What decreases broncho-motor tone?
Sympathetic stimulation of B2 receptors by adrenaline
How does sabutamol work?
It is a B2 agonist that increases cAMP levels in target cells to induce smooth muscle relaxation, mast cell stabilisation (anti-histamine) and improved mucus clearance due to cilia activity
What does arterial baroreceptor stimulation cause?
Inhibits ventilation
What are the attachments of scalene muscles?
Proximally, the scalene muscles attach to cervical vertebrae and distally to first and second ribs
Where are irritant receptors located?
Between airway epithelial cells
Which muscles are used during quiet expiration and what is their action?
Expiration is quite a passive process, only the intercostals contract to prevent intercostal spaces bellowing outwards. Expiration really occurs due to relaxation of inspiratory muscles and elastic recoil of lungs.
What is adherence?
The extent to which the patient’s behaviour reflects agreed recommendations from practitioner
What factors affect the effectiveness of a placebo?
Size, shape, colour of pill, administration of medication. Setting: at home, in hospital. Patient’s characteristics (beliefs, anxiety, adherence) Practitioner characteristics: status, empathy. Patient-Dr. relationship
What is the laryngeal inlet?
The superior margin of the larynx
What is bronchial thermoplasty?
Radio-frequency ablation of parts of the airway to reduce smooth muscle contractility.
Where does the aorta pass through the diaphragm?
Posteriorly