Spinal Cord

Question 1

If lesion in left side of anterolateral column…

Answer 1

Will lose pain and temperature sensation from the right side (contralateral) side of the body

Question 2

If lesion on left side of Dorsal Column-medial Lemniscal pathway

Answer 2

Will lose fine touch and proprioception of the left side (ipsilateral) side of body.

Question 3

If you were a doctor who needs to get some CSF out of a patient where would you draw it out and why?

Answer 3

Lumbar cistern because you wont damage the spinal cord!!!

Question 4

Gray matter in spinal cord

Answer 4

Dorsal horn on top - sensory function
Ventral horn on bottom - movement

Question 5

Gray matter

Answer 5

Nervous system consisting mainly of neuronal cell bodies, dendrites and synapses

Question 6

White matter

Answer 6

Bundles of myelinated axons

Question 7

Ventral Root

Answer 7

Motor fibers

Question 8

Dorsal Root

Answer 8

Sensory fibers

Question 9

Dorsal root ganglion (DRG)

Question 10

Ganglion

Answer 10

Collection of cell body’s in the PNS
Organized cluster of neuronal cell bodies in the PNS

Question 11

Nucleus (Nuclei)

Answer 11

An organized cluster of neuronal cell bodies in the CNS

Question 12

How many pairs of spinal nerves run down the length of the spinal cord?

Answer 12

31 pairs

Question 13

Dermatome

Answer 13

A pair of spinal nerves innervating a region of the body surface

Question 14

Interneurons

Answer 14

Connect the sensory and motor neurons

Question 15

Autonomic neurons

Answer 15

Neurons leave through ventral roots and synapse with post-ganglionic neurons that act on lungs and heart and autonomic functions.

Question 16

Fine touch pathway

Answer 16

Enters through dorsal root
Bypasses gray matter and goes into white matter, little slit of white matter between the two dorsal horns, then it turns upward and heads up to the brainstem.

Question 17

Describe where on the spinal cord the dorsal column (column of axons) is located

Answer 17

Dorsal side of spinal cord, white matter, at the left, between the two dorsal horns of grey matter

Question 18

Where, other then the dorsal column, do neurons on the fine touch pathway synapse?

Question 19

Pain and temperature pathway

Answer 19

1) Comes in through dorsal pathway
2) Second order neuron synapses on grey matter, dorsal horn of the spinal cord
3) Neuron cross over to the other side down to ventral area of grey matter and passes out ot white matter of anterolateral column white then goes up to the thalamus

Question 20

Why is it called the anterolateral pathway?

Answer 20

Because it is in the anterior and lateral part of the spinal cord.

Question 21

Fibers in medial part correspond to _____ and fibers in lateral part correspond to _____.

Answer 21

Fibers in dorsal column are very organized.
Medial part correspond to legs
Lateral part correspond to arms

Question 22

Somatotopic organization(map)
Topography

Answer 22

There is essentially a map of the body in the dorsal column that goes from medial to lateral.

Question 23

Is there a somatotopic map of the body at every level up until the cerebral cortex?

Answer 23

YES

Question 24

Are the anteriolateral columns somatotopically orgranized?

Answer 24

YES

Question 25

Central Pattern Generators

Answer 25

Intrinsic circuitry of the spinal cord forms central pattern generators responsible for rhythmic movements like walking, scratching and the rhythmic motions of swimming fish

Question 26

Spinal reflexes

Answer 26

Simplest goal-directed movements
Involuntary coordinated patterns of muscle contraction and relaxation. Elicited by peripheral stimuli
Sensory stimuli come from receptors in muscle, joints and skin
They produce complex movements that serve protective and postural functions - e.g withdrawal reflex, stretch reflex

Question 27

Withdrawal reflex

Answer 27

Put hand on hot stove then move it away

Question 28

Stretch reflex

Answer 28

Tendon is stretched when knee is tapped.
Tendon is connected to muscle, when muscle gets stretched that activates sensory neurons in the muscle that detect muscle stretch (Muscle spindle)
When sensory neurons detect this stretch they begin to fire action potentials
These enter the spinal cord, go through the spinal cord grey matter and make direct excitatory synapses with flexor muscle and excitatory synapse with inhibitory neuron of extensor muscle

Question 29

Why stretch reflex?

Answer 29

Imagine holding box of books then more books are added so your arms go down a bit then back up.
It’s for posture and protection

Question 30

Can descending inputs from higher brain areas modify and regulate reflexes?

Answer 30

Reflexes are at the level of the spinal cord but they can be modulated and regulated and gated by higher brain centers depending on circumstance

Question 31

Fiber tract (tract)

Answer 31

Bundle of axons in CNS

Question 32

Nerve

Answer 32

Bundle of axons in PNS

Question 33

Projections

Answer 33

Axons that extend from one region of the nervous system to another

Question 34

3 parts of Brainstem in order of top to bottom on mid-saggital cut

Answer 34

1) Midbrain
2) Pons
3) Medulla