Reflexes

Question 1

Where are proprioceptors located?

Answer 1

1. Skeletal muscles (muscle spindles). 2. Tendons (golgi tendon organs). 3. Joints (free nerve endings).

Question 2

What are the functions of proprioceptors? (3)

Answer 2

1. Monitor tension, pressure, and movement at the joint. 2. Send input on body movements to the CNS. 3. Sense of body position results from the integration of this information with sensory info from the internal ear.

Question 3

What is a reflex arc?

Answer 3

A rapid, automatic, involuntary reaction of muscles to a stimulus.

Question 4

What does it mean for a reflex arc to be ipsilateral?

Answer 4

Both the receptor and effector organs are on the same side.

Question 5

What does it mean for a reflex arc to be contralateral?

Answer 5

Sensory impulses from a receptor organ cross over through the spinal cord to activate effector organs on the opposite limb.

Question 6

What is a monosynaptic reflex?

Answer 6

1. Direct communication between sensory and motor neurons. 2. It synapses once in the spinal cord.

Question 7

What is a polysynaptic reflex?

Answer 7

1. Inter-neuron facilitates sensor-motor communication. 2. It synapses twice in the spinal cord.

Question 8

What is a muscle spindle?

Answer 8

A proprioceptor that monitors the length/stretch of a muscle.

Question 9

What results in the patellar tendon reflex?

Answer 9

When a stimulus results in the stretching of a muscle, muscle spindles stretch the muscle reflexively.

Question 10

What are golgi tendon organs; what do they do? Where are they located?

Answer 10

They are a proprioceptive sensory receptor organ that senses changes in muscle tension. They are nerve endings located within tendons near a muscle-tendon junction.

Question 11

What is the golgi tendon reflex?

Answer 11

When the golgi tendon organs are stimulated and send nerve impulses which signal interneurons in the spinal cord, which in turn inhibit the actions of the motor neurons.

Question 12

Is the golgi tendon reflex monosynaptic or polysynaptic?

Answer 12

Polysynaptic.

Question 13

Describe the polysynaptic withdrawal reflex. (4)

Answer 13

1. Painful stimulus is sensed by free nerve ending in the skin. 2. Sensory info is sent to spinal cord. 3. Interneurons receive info and stimulate motor neurons to direct flexor muscles to contract. 4. Simultaneously, extensor muscles are inhibited.

Question 14

Is the patellar tendon reflex monosynaptic or polysynaptic?

Answer 14

Monosynaptic.

Question 15

What does a present patellar reflex indicate?

Answer 15

That spinal nerves and spinal segments L2-L4 are undamaged.