The contraction of the diaphragm and the external intercostal muscles begins inspiration. Explain exactly what happens, in terms of volume and pressure changes in the lungs, when these muscles contract.
What will be an ideal response?
With contraction of the diaphragm, the height of the thoracic cavity increases. Contraction of the intercostal muscles expands the diameter of the thorax. With an increase in volume of the thorax, the intrapulmonary volume increases, causing a drop in pressure relative to atmospheric pressure. Air rushes into the lungs along this pressure gradient until intrapulmonary and atmospheric pressures are equal.
You might also like to view...
The neuromuscular junction
a. is the junction between a motor neuron and a skeletal muscle fiber b. transmits an action potential between the nerve cell and muscle cell on a one-to-one basis c. may produce either an EPSP or an IPSP on the motor end plate d. has all of the above characteristics e. has characteristics a and b
The pubertal process is initiated by an increase in GnRH activity
Indicate whether the statement is true or false
In a patient with Argyll Robertson pupil, you could expect to find:
A. loss of the accommodation response B. loss of pupillary constriction when looking at near objects C. no pupillary response to anticholinergics applied to the affected eye D. a history of syphilis E. ptosis
Which skin infection is caused by a virus?
A. Tinea infections B. Cancer C. Warts D. Cellulitis