Ch 13.5 -- Control of Respiration -- VTPP 435

Ch 13.5 -- Control of Respiration -- VTPP 435

3 distinct components of neural control of respiration

1. factors that generate alternating inspiration-expiration rhythm
2. factors that regulate magnitude of ventilation to match body needs
3. factors that modify respiratory activity to serve other purposes

Medullary Respiratory Center

-several aggregations of neuronal cell bodies in medulla
-provide output to respiratory muscles
-generates rhythmic pattern of breathing
-DRG & VRG

Dorsal Respiratory Group (DRG)

-inspiratory neurons that supply inspiratory muscles
-fire to allow breathing
-has interconnections to VRG

Ventral Respiratory Group (VRG)

-inspiratory and expiratory neurons
-inactive during regular breathing
-inspiratory neurons stimulated by DRG to rev up breathing
-expiratory neurons stimulate expiratory muscles during active exhaling

Pre-Bӧtzinger Complex

-region in upper end of VRG
-neurons display pacemaker activity
-determinate rate at which DRG neurons fire

Pneuomtaxic Center

-sends impulses to DRG to stop breathing
-dominates over apneustic center

Apneustic Center

-prevents inspiratory neurons from being switched off

Apneusis

-abnormal breathing of prolonged inspiratory gasps and abruptly interrupted by brief expirations

Hering-Breuer Reflex

-triggered when tidal volume is greater than 1 L
-Pulmonary Stretch Receptors send action potentials to medullary center and inhibit inspiratory neurons to prevent overinflation

Peripheral Chemoreceptors

-carotid and aortic bodies that respond to change in arterial PO2, PCO2, and H+
-Carotid Bodies and Aortic Bodies

Central Chemoreceptors

-receptors in medulla near respiratory center
-respond to CO2 induced H+ concentration in brain ECF
-adjust ventilation
-Aortic and Carotid

Apnea

-transient interruption of ventilation with breathing resuming spontaneously
-central chemoreceptors less sensitive to arterial PCO2 during sleep

Sudden Infant Death Syndrome (SIDS)

-when baby has sleep apnea that they cannot recover from
-causes death
-unknown cause

Dyspnea

-mental anguish associated with unsatiated desire for more adequate ventilation
-might feel short of breath even though not actually short of air