Question

all movements of breathing stops at once when the nerves leading from the brain to the respiratory muscle are cut?

Answer 1

Answer:

Explanation:

• The rhythmic cycle of breathing originates in the medulla. Higher brain centers (voluntary control), systemic receptors, and reflexes modify the medulla's output. However, no truly separate inspiratory and expiratory centers have been identified.
• The medulla does contain several widely dispersed groups of respiratory-related neurons that form dorsal and ventral respiratory groups.
• fig 9-1.jpg
• Fig. 9-1.  Schematic illustration of the respiratory components of the lower brainstem (pons and medulla oblongata).
• PNC = pneumotaxic center; APC = apneustic center; DRG = dorsal respiratory group; VRG = ventral respiratory group; CC = central chemoreceptors.
• Dorsal respiratory groups (DRG)
• Composed mainly of inspiratory neurons located bilaterally in the medulla, the DRG controls the basic rhythm of breathing by triggering inspiratory impulses.
• These neurons send impulses to the motor nerves of diaphragm and external intercostal muscles.
• DRG nerves extend into the VRG, but the VRG neurons do not extend into the DRG.
• Vagus and glossopharyngeal nerves bring sensory impulses to the DRG from the lungs, airways, peripheral chemoreceptors, and joint proprioceptors.
• Input modifies the breathing pattern.
• Ventral respiratory groups (VRG)
• Contain both inspiratory and expiratory neurons located bilaterally in the medulla and primarily active in exercise and stress.
• VRG sends inspiratory impulses to
• Laryngeal and pharyngeal muscles - (from neurons located in the nucleus ambiguus)
• Diaphragm and external intercostals - (from neurons located in the rostral area of the nucleus retroambigualis)
• Other VRG neurons send expiratory signals to abdominal muscles and internal intercostals - (from neurons in the caudal area)
•  
• Inspiratory ramp signal: Interaction between the DRG and VRG inspiratory neurons:
• Signal starts low and gradually increases to produce a smooth inspiratory effort instead of a gasp.

Answer 2

Answer:

All movements of breathing stop at once when the nerves leading from the brain to the ___are cut.