21 - Breathlessness

Question 1

What is breathlessness

Answer 1

Undue awareness of breathing or awareness of difficulty breathing

Question 2

What causes dyspnoea

Answer 2

o Central information processing
 Compares the afferent and efferent signals
 Dysponea when mismatch between two
 Need for ventilation (afferent signalling) not met by physical breathing (efferent signalling)

Question 3

Where are the respiratory centres

Answer 3

Pons - pneumotaxic centre + apneustic centre

Medulla -VRG, DRG

Question 4

Afferents of resp pathway

Answer 4

Cortex, baroreceptors, peripheral chemoreceptors,
Central chemoreceptors,
Hypothalamus

Question 5

What does peripheral chemoreceptors detect

Answer 5

PO2
Ph
pco2

Question 6

What do J receptors detect

Answer 6

Pulmonary Oedema

Question 7

Respiratory efferents

Answer 7

o Expiratory muscles
o Phrenic nerve – Diaphragm
o Intercostal nerve – Intercostals
o Pharyngeal dilator muscles

Question 8

How does hypoxia cause breathlessness

Answer 8

o All causes of type 1 resp failure can cause breathlessness via peripheral chemoreceptors
o Type 2 resp failure  hypoventilation = NOT BREATHLESSNESS e.g. COPD, asthma, chr bronchitis

Question 9

Causes of breathlessness

Answer 9

Hypoxia