The nerves that innervate the diaphragm arise from which area? ...

[WWatsford]

The nerves that innervate the diaphragm arise from which area?
 
  a. Lumbar region of the spine
  b. Sacral vertebrae 4 and 5
  c. Spinal plexuses at T2 to T11
  d. Spinal nerves C3 to C5

Question 2

Limited, short-term spontaneous ventilation is possible in a patient with a paralyzed diaphragm because of_________________ ____.
 
  a. reflex diaphragm activity
  b. accessory muscle use
  c. active exhalation
  d. high intraabdominal pressures

[upturnedfurball]

Answer to Question 1

ANS: D
Functionally, the diaphragm is divided into a right and left hemidiaphragm. Each hemidiaphragm is innervated by a phrenic nerve that arises from branches of spinal nerves C3, C4, and C5.

Answer to Question 2

ANS: B
Although the diaphragm is the primary ventilatory muscle, it is not essential for survival. Limited, short-term ventilation is possible using accessory muscles, even if the diaphragm is paralyzed. The diaphragm does not actively participate in exhalation. During exhalation, it returns to its resting position during the passive recoil of the lungs and thorax. During forced exhalation, abdominal wall muscles compress the abdominal cavity and increase pressure in the abdominal cavity. This forces the diaphragm upward and compresses the lungs and forces gas from them. The dia-phragm performs important functions other than ventilation. It aids in generating high in-traabdominal pressures by remaining fixed while the abdominal muscles contract. This facilitates vomiting, coughing, sneezing, defecation, and parturition.