Respiratory responses Flashcards
What are the physical barriers to irritation/invasion of the respiratory tract?
- Nares, nasal cavity, pharynx, larynx
- Terminal bronchioles
- Mucociliary escalator
- Pseudostratified columnar epithelium with goblet cells
- Alveolar macrophages
Rapidly adapting receptors respond to changes in?
Mechanical properties e.g. stretch, mainly in intrapulmonary airways
When do rapidly adapting receptors become more active?
As rate and volume of lunch inflation increases during normal respiration
What effect do rapidly adapting receptors have on airways?
Reflex bronchoconstriction and mucus secretion
What do C-fibres respond to?
Noxious chemical and mechanical stimuli
What are C-fibres directly activated by?
Bradykinin and capsaicin
Where are slowly adapting receptors found?
Around bronchioles and alveoli
How does inspiration and expiration affect the activity of slowly adapting receptors?
Increases during inspiration and decreases during expiration
What is the afferent nerve of the cough reflex?
Vagus nerve
Is the coughing reflex unconscious or conscious?
It is automatic but there is a degree of conscious control as it can be suppressed
Where is the cough centre?
Medulla and pons
Where are some mechanical receptors for the cough reflex found?
Pharynx, ear canal, eardrum, paranasal sinuses, diaphragm, pleura, pericardium and stomach
Efferent impulses to generate a cough are sent via which routes?
Phrenic nerve - to the diaphragm
Spinal motor nerves - to abdominal wall muscles
Respiratory centre - stimulates muscles of inspiration and expiration
Vagus and laryngeal nerve - to the larynx
What are the 3 mechanical phases to a cough?
- Inspiratory
- Compression: Glottis and larynx close which builds pressure in the thorax
- Expiratory
Where are receptors for the sneeze reflex found?
Nasal mucosa
