8- Sensory Aspects Of Respiratory Disease Flashcards
Where are cough receptors mainly found
MOST NUMEROUS on the POSTERIOR WALL of the trachea
Proximal airways
ABSENT beyond the bronchioles
What are the 3 types of sensory receptor in the lungs
SLOW adapting stretch receptors
RAPIDLY adapting stretch receptors
C-fibre receptors
Describe the 3 types of sensory receptor
C fibre receptors
Present in the upper airways - larynx, trachea, bronchi and lungs
They are small UNMYELINATED fibres - so conduction is SLOW Responds to chemical irritant stimuli and inflammatory mediators
• Rapidly adapting stretch receptors
MYELINATED - so conduct very quickly
Present in the naso-pharynx, larynx, trachea and bronchi
Mechanical, chemical irritant stimuli, inflammatory mediators
If you stimulate them with hyperinflation there is a rapid response
• Slowly adapting stretch receptors
Located in airway smooth muscle
Also MYELINATED - so conduct very quickly
Predominantly in the trachea and main bronchi
• They respond to lung inflation
What can activate mechanoceptors and nociceptors
MECHANOSENSORS are activated by: Mechanical Displacement CITRIC ACID • NOCICEPTORS are activated by: Caspaicin Bradykinin Citric Acid Cinnamaldehyde
Describe the cough pathway
Sensory information goes via the vagus nerve and through the brainstem to the cough centre
• The cough centre consists of the nucleus tractus solitarius - a collection of neurons that are connected to the medullary cough pattern generator
Muscles stimulated
What is the most common cause of acute cough
Rhinovirus
What are common causes of acute cough
Asthma and eosinophilic-associated - 25% Gastro-oesophageal reflux - 25% Rhinosinusitis (post-nasal drip) - 20% Chronic Bronchitis - 8% Bronchiectasis - 5% Drugs (e.g. ACE inhibitors) - 1%
What are the 3 phases of cough
Inspiratory Phase Glottic Closure Expiratory Phase
How can you get increased hypersensitivity syndrome
Increased excitability of the afferent nerves by chemical mediators e.g. prostaglandin E2
• Increase in receptor numbers e.g. TRPV1
• Increase in neurotransmitter in the brainstem e.g. neurokinins
What can cause chest pain from the resp system
Pleuropulmonary disorders:
Pleural inflammation eg infection, pulmonary embolism,
Pneumothorax, malignancy eg mesothelioma
• Tracheobronchitis:
Infections, inhalation of irritants
• Inflammation or trauma to chest wall:
Rib fracture, Muscle injury, Malignancy, Herpes zoster (intercostal
Nerve pain)
What is Dyspnoea
Troublesome shortness of breath reported by a patient
•Occurs at inappropriately low levels of exertion, and limits exercise tolerance
How are the anatomical pathways if touch and pain different
TOUCH - goes to the contralateral side at the level of the caudal medulla (brainstem)
EXAMPLE: the sensation of touch from the leg will run up along the same side as the leg it is coming from and then cross onto the other side at the brainstem
• PAIN - goes to the contralateral side at the same anatomical level (it crosses right away)
• Both touch and pain information goes to the primary somatosensory cortex
What can be used to determine breathlessness
Modified Borg scale
Respiratory descriptors
Clinical Dyspnoea scale
