Spinal Reflexes

Question 1

Occur without direct involvement of higher brain centers.

Answer 1

Spinal Reflexes

Question 2

Provide the nervous system with information about the length of a muscle.

Answer 2

Muscle Spindles

Question 3

Provide the nervous system with information about the tension in a muscle.

Answer 3

Tendon Organs.

Question 4

Modified skeletal muscle fibers in muscle spindles that are enclosed in connective tissue capsules. Mostly noncontractile, but have contractile regions at their ends. Receptive surface of the spindle.

Answer 4

Intrafusal Muscle Fibers

Question 5

Effector fibers of the muscle.

Answer 5

Extrafusal Muscle Fibers

Question 6

Endings of large axons that wrap around the muscle spindle center. Stimulated by both rate and degree of stretch.

Answer 6

Anulospiral Endings

Question 7

Smaller axons that supply the spindle ends. Stimulated by degree of stretch.

Answer 7

Flower Spray Endings

Question 8

Innervate the contractile regions of intrafusal muscle fibers. Arise from small motor neurons in the ventral horn of the spinal cord.

Answer 8

Gamma Efferent Fibers

Question 9

Innervate the extrafusal muscle fibers.

Answer 9

Alpha Efferent Fibers

Question 10

Stimulated the extrafusal muscle fibers to contract.

Answer 10

Alpha Motor Neurons

Question 11

Descending fibers of mother pathways synapse both motor neurons so that motor impulses are simultaneously sent to the large extrafusal fibers and to muscle spindle intrafusal fibers.

Answer 11

Alpha-Gamma Coactivation

Question 12

Causes muscle contraction in response to increased muscle length to make sure that muscles stay at the length set by the brain. Important for maintaining muscle tone.

Answer 12

Stretch Reflex

Question 13

A stretch reflex that prevents knees from buckling when you are standing upright.

Answer 13

Patellar Reflex

Question 14

Occurs when branches of afferent fibers from muscle spindles synapse with interneurons that inhibit motor neurons controlling antagonistic muscles.

Answer 14

Reciprocal Inhibition

Question 15

All stretch reflexes are these types

Answer 15

Monosynaptic and Ipsilateral.

Question 16

Reflexes that involve motor activity on the same side.

Answer 16

Ipsilateral

Question 17

Cause muscles to relax in response to tension. Help prevent muscles and tendons from tearing when they are subjected to potentially damaging stretching force.

Answer 17

Tendon Reflexes

Question 18

Occurs when motor neurons in spinal cord circuits supplying contracting muscles are inhibited and antagonist muscles are activated.

Answer 18

Reciprocal Activation

Question 19

Initiated by a painful stimulus. Causes automatic withdrawal of the threatened body part from the stimulus.

Answer 19

Flexor Reflex

Question 20

Flexor reflexes are these types.

Answer 20

Ipsilateral and polysynaptic

Question 21

Occurs when incoming afferent fibers synapse with interneurons that control the flexor withdrawal response on the same side of the body and with other interneurons that control extensor muscles on the opposite side.

Answer 21

Crossed-Extensor Reflex

Question 22

Elicited by gentle cutaneous stimulation.

Answer 22

Superficial Reflexes

Question 23

A superficial reflex that occurs when stroking the skin of the lateral abdomen above, to the side, or below the umbilicus and induces a reflex contraction of the abdominal muscles.

Answer 23

Abdominal Reflexes

Question 24

A superficial reflex that occurs when stroking along the lateral aspect of the plantar surface of the foot, causing the toes to flex downward.

Answer 24

Plantar Reflex