Control of Respiration Flashcards
Which part of the brain is the main rhythm generator for breathing?
Medulla
What are the specialised neurones that generate rhythmical breathing called?
Pre-Botzinger complex
What are the steps of neuronal stimulation that causes inspiration?
- Pre-Botzinger generates rhythm
- Excites dorsal neurones
- Fire in bursts
- Firing of neurone causes contraction of inspiratory muscle.
- When firing stops- passive expiration
Which group of neurones generate active expiration using accessory muscles?
Ventral neurones–> excite internal intercostals, abdominal muscles
Major muscles of inspiration?
- Diaphragm
2. External intercostal muscles
Accessory muscles of inspiration?
- Sternocleidomastoid
2. Scalenus
Muscles used in active expiration?
- Internal intercostals
2. Abdominal muscle
Which part of the brain terminates inspiration, allowing passive expiration?
Pons. Known as the pneuotaxic centre.
What would happen if the pneumotaxic centre was dysfunctional?
Apneusis- Prolonged inspiratory gasps with brief expiration
What is the Apneustic area responsible for?
Can prolong inspiration by exciting the inspiratory area of the medulla
What types of stimuli are the respiratory brain centres responsive to? (5)
- Higher brain centres
- Stretch receptors
- Juxta-pulmonary receptors
- Joint receptors
- Baroreceptors
What is the Hering Breuer reflex?
Pylmonary stretch receptors that inhibit inspiration.
Prevent hyper-inflation of the lungs.
What are the effects of the joint receptors?
Impilses from moving limbs that increase breathing.
Increases ventilation in exercise
What other factors can increase ventilation during exercise? (3)
- Adrenaline
- Impulses from cerebral cortex
- rise in temperature
What are the steps involved in the cough reflex? (4)
- Short breath intake
- Closure of larynx
- Contraction of abdominal muscles
- Larynx opens, expulsion of air at high speed
