Respiratory Control Flashcards
Describe the control centres in the brain stem:
Pons respiratory centre: Pneumotaxis and apneustic centre
Medulla respiratory centre: Dorsal and Ventral respiratory group (DRG and VRG)
Pre-botzinger complex
what controls tidal rhythm?
DRG controls phrenic nerve APs
Increase phrenic nerve APs = diaphragm contracts
Decrease phrenic nerve APs = diaphragm relaxes
Which centres are responsible for tidal and forced breathing?
Tidal - DRG. Pontine (pons) centre. Responds to chemoreceptors (CO2) and activates respiratory muscles.
Forced - VRG. VRG is inactive during tidal, but activates extra muscles mainly for expiration.
What do the two components of the pontine respiratory centre do?
APneustic area prolongs inspiration (decreases breathing rate)
Pneumotaxic area limits inspiration (increases rate of breathing)
What are central chemoceptors in the medulla most sensitive to?
Changes in H+ concentration in CSF
Where are peripheral chemoreceptors found, and what do they measure?
Found in carotid and aortic arteries.
Measure oxygen in arterial blood, but large drops in PO2 must occur for peripherla chemoreceptors to stimulate increased ventilation.
Which receptors respond to mechanoirritants?
Myelinated upper airway pulmonary receptors.
Respond to irritation of airways by touch by stimulating coughing and gasping
Which receptors respond to chemicals in airways?
Non-myelinated pulmonary receptors cause bronchoconstriction and mucus secretion in response to chemicals such as capsaicin.
What is the Hering-Breuer Reflex?
Stretch receptors in pleurae and airway are stimulated by lung inflation.
Prevents over-inflation of lungs.
Describe the cough reflex.
Mechanoreceptors stimulate the vagus nerve to cause coughing.
Receptors located in larynx, bronchi, trachea (upper airway)
How does blood CO2 change during exercise?
Blood CO2 drops during exercise , due to increased ventilation.
When you finish exercise, respiration decreases, but muscles continue to release CO2, causing blood CO2 to increase.
