A young wife is talking with the nurse about her husband who is returning from the military. The wife confides that her husband is physically okay but is behaving differently. What is the nurse's best response?

A) "He is just trying to adjust to civilian life again; he'll be okay."
B) "You should observe him closely, because he could attack you."
C) "Many times people need care for emotional trauma."
D) "Talk with your physician to get medication, and then put it in his food."

Thin nerve filaments that go to the ventricular muscle tissue are the ________.