Question

50) In an electrocardiogram (ECG/EKG), the QRS complex represents

A) depolarization of the atria

B) both the depolarization of the ventricles and repolarization of the atria simutaneously

C) repolarization of the ventricles

D) firing SA node

51) The autonomic nervous system

A) has a single nerve cell extending from the spinal cord to the target organ

B) uses only acetycholine as a neurotransmitter

C) usually produces hypersensitivity in a target organ when removed

D)innervates skeletal muscle

E) is under conscious control

52) Which of the following is NOT a feature of the sympathetic division of the ANS?

A) it has extensive neural divergence with relatively widespread effects of short duration

B) it has short preganglionic fibers

C) it has terminal ganglion adjacent to the target organ

D) it originates in the thoracolumbar region of the spinal cord

E) it has long postganglionic fibers

53) In the cochlea, how is pitch encoded and sent to the brain?

A) by the frequency of nerve impulses along the cochlear nerve.

B) by the location along the cochlea that is stimulated; low pitches are near the oval window.

C) by the action of the tectorial membrane.

D) by recruiting additional nerve fibers to transmit the signal in the vestibulocochlear nerve.

E) by the location along the cochlea that is stimulated; high pitches are near the oval window.

Answer 1

50. (B) Both the depolarization of ventricles and repolarization of the artria simultaneously. [wave of artrial repolarization has very low amplitude, so it is not visible in ecg and is covered up by QRS complex]

51.(C) Usually produces hypersensitivity in a target organ when removed.

52.(E) It has long postganglionic fibers [sympathetic nervous system has short postganglionic fibers]

53.(E) By the location along the cochlea that is stimulated, high pitches are near the oval window.