Sensory aspects of respiratory disease Flashcards
- Describe the pathway from stimulus to evoked sensation? What are the names for the two main parts of this?
Sensory stimulus->transduced->excitation of nerve->CNS integration->impression
That is neurophysiology-the sensory impression from activation of a pathway
Sensory impression->perception->evoked sensation –the brain interprets the information-can be different in different people
- Describe the distribution of rapidly adapting irritant receptors within the airway epithelium.
Most are found in posterior wall of trachea, carine, and less present in distail airways-completely absent in brocnhials, only proximal aiways
Common at branching points
- What are the three main types of sensory receptors in the lungs and airways?
Slow adapting stretch receptors, rapidally adapting stretch receptors and C-fibre receptor
- Which nerve do all the sensory receptors in the lungs and airways pass through?
For lung and airway (not trachea)-Vagus
- What is used as a stimulus for the C-fibres?
C-fibers depend on CHEMICALs to be activatied-in experiments often capsaicin. These have no effects on the stretch receptors
- What stimulates C-fibres?
Chemicals (eg capsaisin)
- What do the rapidly and slowly adapting stretch receptors respond to?
Increases and decreases in INFLATION. Eg: tracheal pressure-rapidelt adapting stop firing, and slow adapting are stimulated (probs most common in cough)
- Describe the differences between the three types of sensory receptor.
C-fibers are non myelinated (so slow), oteher two ARE
C fiber respondchemicals, other two are mechanoreceptors. Both respond to irritants and inflame mediators
- What are the two broad types of sensory receptor in the airways that lead to cough?
Mechanoreceptors (fast and slow) (activated by mechanical displacement and Citric acid and Nociceptors (chemical C-fibres-activated by capsaicin, dradykinin, citric acid, cinnamaldheyde)
- Other than mechanical displacement, what else activates the mechanoreceptors?
Citric Acid
- What is the collection of neurons in the cough centre called?
Sensory info arrives to the Nucleus tractus solitatus, connected to medullary cough pattern generator-so brainstem reflex
- What is this collection of neurons connected to?
The medullary cough pattern generator –they then generate through spinal chord a cough
- What is the role of the cerebral cortex in the complete cough pathway?
Acts of sleep, sensitising, urges to coughs
- What are the three phases of cough?
Inspiration, glottic closure (rise of pressure) and expiratory phase
- Describe the afferent and efferent pathways of cough
Afferent-sense signal goes back up using vagus nerve (or laryngeal If in treahcea and stuff)-to nTR and cortex. Both to medulla cough centor, which send signals back down to intercostals, diaphragm, glottis and stuff
- What is acute cough and what is it usually caused by?
<3weeks-often caused by rhinovirus
- What are the causes of chronic cough?
> 3 weeks- asthla, GORD, Rhinosinisitis, drugs
- What is another name for chronic cough? How can the sensitivity be tested?
Also known as cough hypersensitivity syndrome –the persons receptors are more sensitive because increase of afferent nerves, increase in receptors and neurotranmotter. Can be tested using caspaicin
- What drugs can inhibit the cortical control of the cough reflex?
Antitussives can be central (opiates like codien, dryhydrocodein), or peripheral (moguistine)
Or disease specific(eosinophil associated-corticosteroids), GORD-proton pump inhib, H2 inhbit
- Sensory perception from the nose and the pharynx goes through which nerves?
Most V and IX
- Describe the anatomical pathways of touch and pain.
Touch and pain differ as
Touch mostly used alpha and beta fibers(myelinated)-and CROSSES in the spine AT the caudal medulla
Pain-C fibers, crosses at the level of where it is (crosses as it enters)
- What is the clinical significance of this?
Brown-Sequard syndrome-if you have a spine hemisection, touch fine on one side but pain on the other
- What’s the difference between somatic and visceral pain?
Visceral is from organs-difficult to localise as less afferent neuron
Somatic is skin and subcutaneous-very localised
- What scale is used to grade dyspnoea?
Clinical dysnpnea scale, or rated on a modified BORG scale
- List some chest pains caused by resp disorders. And some that are not
Resp pain- pleuritic, tracheobronchitis, rib fracture, referred pain
Non resp-CVD-MI, pericarditis, aneurysm, GI-Oesophageal rupture, GORD, Pysch-panic disorder
- What are the three types of dyspnoea?
Hunger for air, tightness, work/effort
