Question

question 4
1 pts
the knee jerk can be classified as a segmental reflex because:
the center of the reflex arc lies in the spinal cord gray matter.
impulses that mediate it enter and leave the same segment of the cord.
the impulses that mediate it come from and go to the same side of the body.
of the kind of stimulation used to evoke it.

question 5
1 pts
the cerebellum performs all of the following functions except:
coordinates control of muscle action.
helps control posture.
controls cardiac function.
controls skeletal muscles to maintain balance.

question 6
1 pts
the parasympathetic and sympathetic divisions always act with a cooperative influence, and through summation of the impulses, the effect can be increased.
true
false

Explanation:

Question 4

A segmental reflex is defined by impulses entering and leaving the same spinal cord segment. The knee - jerk reflex (patellar reflex) is a simple reflex arc. In a segmental reflex, the sensory neuron (carrying the impulse from the receptor) and the motor neuron (carrying the impulse to the effector) interact within the same spinal cord segment.

• The first option about the center in the spinal cord gray matter is too general as many reflexes have centers in the gray matter.
• The third option about the same side of the body is not the defining characteristic of a segmental reflex.
• The fourth option about the type of stimulation is not relevant to the segmental nature of the reflex.

The cerebellum is mainly involved in motor control. It coordinates muscle action (e.g., smooth execution of movements), helps control posture (by adjusting muscle tone), and controls skeletal muscles to maintain balance (through its input to the vestibular system). However, cardiac function is primarily controlled by the autonomic nervous system (specifically the medulla oblongata for basic cardiac rhythm and the autonomic ganglia for modulation) and not by the cerebellum.

The parasympathetic and sympathetic divisions are often antagonistic. For example, the sympathetic division increases heart rate and the parasympathetic division decreases heart rate. They do not always act cooperatively. Summation of impulses is a concept related to neural integration at the synaptic level but does not change the fundamental antagonistic relationship between these two divisions in most cases (e.g., in the regulation of the digestive system, sympathetic inhibits and parasympathetic stimulates digestion).

Answer:

impulses that mediate it enter and leave the same segment of the cord.

Question 5