Physiology 6 Flashcards
What 2 factors control respiration?
NeuralHormonal
What control the rhythmicity (inspiration followed by expiration) of breathing?
Neural control
What are the 3 parts of the brainstem?
The midbrainPonsMedulla oblongata
What part of the brain is the major rhythm generator?
Medulla
What are the respiratory centres of the pons? (2)
Pneumotaxic centreApneustic centre
What are the respiratory centres of the medulla? (3)
Pre-Botzinger complexDorsal respiratory groupVentral respiratory group
What 2 parts of the brain stem have respiratory control centres in them?
Pons respiratory centresMedullary respiratory centres
What network of neurones generates the breathing rhythm?
Pre-botzinger complex
What are pacemakers?
a group of cells or a body part (as the sinoatrial node of the heart) that serves to establish and maintain a rhythmic activity e.g. the neurones of the pre-botzinger complex display pacemaker activity
What does the Pre-botzinger complex do with the rhythm it generates?What does this cause?
Excites dorsal respiratory group neurones which fire in bursts leading to contraction of inspiratory muscles = inspiration
What causes passive expiration?
When the firing from dorsal respiratory group neurones stops
Is the dorsal respiratory group neurones concerned with inspiration or expiration?
Inspiration
What causes “active” expiration during hyperventilation?
Increased firing of dorsal neurones excites the ventral respiratory group neuronesThese excite internal intercostal muscles and muscles in the abdominal wall causing forceful expiration
What are the major muscles of inspiration? (contract every inspiration; relaxation causes passive expiration)
External intercostal musclesDiaphragm
Accessory muscles of inspiration? (contract only during forceful inspiration)
ScalenusSternocleidomastoid
What ar the muscles of active expiration (contract only during active expiration)?
Internal intercostal musclesAbdominal muscles
What is the purpose of the pons respiratory centres?
To modify the rhythm generated in the medulla
What does stimulation of the pneumotaxic centre do?When is the PC stimulated?
Terminates inspirationWhen dorsal respiratory neurones fire
What is breathing like without a functioning pneumotaxic centre?
Prolonged inspiratory gasps with brief expiration called apneusis
What is the purpose of the apneustic centre?
To excite inspiratory area of medulla prolonging inspiration