Control of RespiratioN

Your respiratory rate changes. When active, for example, your respiratory rate goes up; when less active, or sleeping, the rate goes down. Also, even though the respiratory muscles are voluntary, you can't consciously control them when you're sleeping. So, how is respiratory rate altered & how is respiration controlled,

• controls automatic breathing
• consists of interacting neurons that fire either during inspiration (I neurons) or expiration (E neurons)
• I neurons - stimulate neurons that innervate respiratory muscles (to bring about inspiration)
• E neurons - inhibit I neurons (to 'shut down' the I neurons & bring about expiration)

Apneustic center (located in the pons) - stimulate I neurons (to promote inspiration) Pneumotaxic center (also located in the pons) - inhibits apneustic center & inhibits inspiration
 
Factors involved in increasing respiratory rate

• Chemoreceptors - located in aorta & carotid arteries (peripheral chemoreceptors) & in the medulla (central chemoreceptors)
• Chemoreceptors (stimulated more by increased CO2 levels than by decreased O2 levels) > stimulate Rhythmicity Area > Result = increased rate of respiration

Heavy exercise ==> greatly increases respiratory rate
Mechanism?

• NOT increased CO2
• Possible factors:
• reflexes originating from body movements (proprioceptors)
• increase in body temperature
• epinephrine release (during exercise)
• impulses from the cerebral cortex (may simultaneously stimulate rhythmicity area & motor neurons).