09 Sensory Aspect of Respiratory Disese

Question 1

What is the expulsive phase of cough involve

Answer 1

Bronchoconstriction

Mucus release

Question 2

Describe C fibre in terms of its

1) Location
2) Myelination
3) Stimuli

Answer 2

1) Larynx, trachea, bronchi, lungs
2) Unmyelinated
3) Chemical irritant and inflammatory mediators

Question 3

Describe rapidly adapting fibres in terms of its:

1) Location
2) Myelination
3) Stimuli

Answer 3

1) Nasopharynx, larynx, trachea, bronchi
2) Myelinated
3) Mechanical, chemical irritant stimuli, inflammatory mediators

Question 4

Describe slowly adapting fibres in terms of its:

1) Location
2) Myelination
3) Stimuli

Answer 4

1) Airway smooth muscles - mainly in trachea and bronchi
2) Myelinated
3) Mechanical

Question 5

Describe slowly adapting fibres in terms of its:

1) Location
2) Myelination
3) Stimuli

Answer 5

1) Airway smooth muscles - mainly in trachea and bronchi
2) Myelinated
3) Mechanical

Question 6

Describe how the three types of sensory receptors react to capsaicin and inflation of the lungs

Answer 6

• Only C fibres react to capsaicin but not inflation
• Rapidly adapting fibres: decrease action potential frequency during inflation
• Slowly adapting fibres: increase action potential frequency during inflation

Question 7

Name some specific stimuli that can activate nociceptors and mechanoceptors

Answer 7

Nociceptors: citric acid, capsaicin, bradykinin
Mechanoceptors: citric acid, stretch displacement

Question 8

Describe the process of how stimuli is sensed

Answer 8

Sensory information goes via vagus nerve to the cough centre which includes NTS (nucleus of solitary tract) connected to medullary cough pattern generator to elicit brainstem reflex by stimulating various muscles

Question 9

State the 3 phases of cough and describe the mechanics behind it

Answer 9

• Inspiratory phase: trachea open to allow inspiration
• Glottic closure
• Expiratory phase: raised intrapulmonary pressure that pushes onto the posterior side of trachea to form a crescent shape

Question 10

List 3 causes of cough

Answer 10

Acute: < 3 weeks: eg rhinovirus
Chronic persistent: > 3 weeks eg asthma and eosinophilic, gastroesophageal reflux, rhino-sinusitis
Chronic cough: indication of increased cough reflex

Question 11

What is the mechanism for increased hypersensitivity to cause chronic cough

Answer 11

Increased excitability in afferent by chemical mediators (eg prostaglandin)
Increased number of receptors (eg TRPV1)
Increased neurotransmitters in brainstem (eg neurokinin)

Question 12

What is the management for cough hypersensitivity

Answer 12

Speech pathology management

Drugs: amitryptiline, opiates

Question 13

State the afferent nerves that sense:

1) nose
2) pharynx
3) larynx
4) lungs
5) chest wall

Answer 13

1) CN V
2) CN IX CN X
3) CN X
4) CN X
5) Spinal nerves

Question 14

Compare the sensory pathway between touch and pain

Answer 14

Touch afferent action potential only crosses to the contralateral side in the medulla where as pain crosses to the contralateral side at the same level of spinal cord it enters

Question 15

Gives examples of chest pain

Answer 15

Respiratory

1) Pleuropulmonary disorder - pneumothorax
2) Tracheobronchitis - infections
3) Inflammation or trauma to chest wall - rib fracture

Non-respiratory

1) Cardiac - MI
2) GIT - gastroesophageal reflux
3) Psychiatric disorder - panic attack

Question 16

Name some assessments for dyspnoea

Answer 16

Modified Borg Scale
Clinical dyspnoea scale
Respiratory descriptors

Question 17

List some disorders leading to dyspnoea

Answer 17

1) Respiratory: pulmonary fibrosis, COPD
2) Cardiovascular: myocardial disease leading to HF, valvular disease
3) Altered central ventilatory drive: metabolic acidosis
4) Physiological response: severe exercise
5) Idiopathic hyperventilation

Question 18

What are the general treatments for dyspnoea

Answer 18

Bronchodilator
Drugs that affect the brain (morphine)
Lung resection
Pulmonary rehabilitation