Neuroanatomy Unit 1

Front 1

What are the two major tracts that relay nociceptive information?

Back 1

Spinothalamic tract and Spinoreticulothalamic

Front 2

Nociceptors typically have______ or_______ diamter axons.

Back 2

A delta or C diameter

Front 3

A delta pain fibers mediate what type of pain?

Back 3

well localized, fast pain, on/off type pain. Associated with spinothalamic tract. A delta fibers are activated by strong mechanical pressure of heat.

Front 4

C fibers mediate what type of pain?

Back 4

Slow pain, not well localized, very disturbing with emotional aspects. Associated with Spinoreticulothalamic tracts. C fibers are probably activated by chemicals.

Front 5

GATE theory for pain

Back 5

suggests nociceptive info. can be modified at teh level of the spinal cord by rubbing an injured area to decrease pain transmission via the excitation of adjacent A beta touch receptors, which "closed the gate on pain"

Front 6

TENS

Back 6

transcutaneous electrical nerve stimulation. Activates large diamter primary touch receptors (such as a beta fibers) electrically.

Front 7

Stimulation of the Periaqueductal Grey (PAG), nucleus raphe magnus, or dorsal raphe nucleus will produce____?

Back 7

Analgesia, the result of teh raphe spinal tract, a descending tract that may affect "gate cells" in the dorsal horn of the spinal cord so they cannot transmit pain upwards.

Front 8

Factors that influence the ascending transmission of pain:

Back 8

1. activity of large diameter, myelinated primary afferents (A beta fibers).
2.descending influences from rostral areas of the CNS.
3. release of endorphins

Front 9

Process by which endorphins block pain:

Back 9

1. Endorphins bind to receptors that block the release of chemicals that transmit pain to the brain.
2. Also, interact with opiate receptors in the brain to reduce the perception of pain

Front 10

Lower Motor Neurons: Alpha

Back 10

Innervates skeletal (extrafusal) fibers. Cell bodies in teh CNS, travels through teh ventral roots, and cranial and spinal nerves. it creates muscle tone and coordinates large voluntary movements.

Front 11

Damage to Alpha motor neurons:

Back 11

Paralysis, decreased muscle tone (hypertonia).

Front 12

Somatic Motor Neurons: Gamma

Back 12

synspse on intrafusal muscle fibers of skeletal muscles, with cell bodies located inside the muscle spindle. Travels throughthe ventral root, cranial and spinal nerves and creates increased sensitivity of a muscle to stretch.

Front 13

Damage to Gamma Motor Neurons:

Back 13

Decreased reflexes (hyporeflexia).

Front 14

Somatic Motor Neurons: Beta

Back 14

Rare, synapse on both extrafusal and intrafusal fibers, with cell bodies in the CNS. Travels through the ventral root, cranial and spinal nerve to innervate muscle fibers.

Front 15

Damage to Motor Neurons: Beta

Back 15

muscle atrophy

Front 16

Where can lower motor neurons be damage and what is the result?

Back 16

A lesion in the ventral horn, ventral roots, spinal nerve, or peripheral nerves. The result is flaccid paralysis, decreased muscle tone (hypertonia), decreased reflexes (hyporeflexia), and muscle atrophy.

Front 17

Nuclear Bag fibers

Back 17

sensitive to changes in muscle length and velocity of change

Front 18

Nuclear Chain fibers

Back 18

sensitive to changes in muscle length.

Front 19

What is the afferent (sensory) innervation of the muscle spindle?

Back 19

1. The primary sensory ending (annulospiral ending).
2. secondary sensory ending (flower spray ending).

Front 20

Annulospirial endings are sensitive to _____?

Back 20

sensitive to muscle length and velocity of change (like nuclear bag fibers)

Front 21

Flower Spray endings are sensitive to what?

Back 21

Muscle length (like nuclear chain fibers).

Front 22

Efferent Innervation of the muscle spindle

Back 22

Gamma motor Neurons sypnapse on the ends of the spindle and when activated, the ends of the spindle contract, putting tension on the equatorial region. The afferent sensory endings sense this and become more sensitive as a result. Thus change withing the muscle is monitored.

Front 23

The muscle spindle is the _____ component of a reflex called the ________.

Back 23

The muscle spindle is the sensory component of a reflex called the stretch reflex. The knee jerk is an example.

Front 24

Golgi Tendon Organs

Back 24

encapsulated free nerve endings that monitor tension in tendons.

Front 25

Reciprocal Inhibition

Back 25

the inhibition of antagonist muscles during agonist contraction. This is used extensively during voluntary movement and makes smooth flowing movements possible.

Front 26

Tonic vs. Phasic Stretch Reflex

Back 26

Tonic reflexes help you maintain muscle tone and posture, phasic reflexes preferentially activates Ia annulospirial endings and results in a brief contraction.

Front 27

Tonic vs. Phasic Stretch Reflex

Back 27

Tonic reflexes help you maintain muscle tone and posture, phasic reflexes preferentially activates Ia annulospirial endings and results in a brief contraction.