Spinal Cord (Back and Spinal Cord Part 1)

Question 1

cell body

Answer 1

contains nucleus and metabolic machineray of cell (trophic)

Question 2

Dendrites

Answer 2

(receptive) form extension into tissues that may synapse on to one or many other neurons

Question 3

Axon

Answer 3

Conductive

also called the “nerve fiber” = a long cytoplasmic process that can transmit nerve impulses over a long distance wihtout diminution of the amplitude of the signal

Question 4

Terminal branches of axon

Answer 4

transmissive, make contact with other neurons at synpases

Question 5

Ganglia

Answer 5

Groups of neuron cell bodies that lie in peripheral to the CNS in vertebrates

Question 6

Pseudounipolar neurons

Answer 6

• somatic sensory neuron in the peripheral nervous system.
• somas in dorsal root ganglia of the spinal cord
• have a single, long axon that splits into two branches
• “peripheral branch” which goes to the skin, joints, and muscles
• “central branch” which goes to the spinal cord
• fibers of the dorsal root ganglion project into the dorsal horn of the spinal cord and synapse with neurons of the dorsal horn.
• axons of dorsal ganglion neurons are also known as afferents nerves.
• 1 axon, no true dendrite
• pseudounipolar neurons that detect changes in the internal and external environment and inform the CNS of the changes; cell bodies of sensory neurons are located in spinal (dorsal root) ganglia in spinal nerves or sensory ganglia of cranial nerves; enter the posterior gray horns of the CNS via posterior roots of the spinal cord or sensory nerves of the cranial nerves

exits cell body and travels through posterior root; enter spinal cord at posterior horn (or brainstem for cranial nerves) where they deliver their action potentials

Question 7

multipolar neurons

Answer 7

has multiple dendrites and a single axon

• includes:
• most neurons
• most CNS neurons (Interneurons)
• all motorneurons
• Cell bodies in the anterior horn of the spinal cord
• axons form the anterior root.

Question 8

multipolar vs pseudounipolar neuron

Answer 8

Question 9

gray matter

Answer 9

H”-shaped gray matter core of spinal cord

• made up of neuronal cell bodies
• organized into anterior horn (motor cell bodies) and posterior horn (sensory cell bodies)
• thoracolumbar region {T1-L/L3) also features a lateral horn
• contains preganglionic sympathetic cell bodies organized into an intermediolateral cell column.

Question 10

white matter

Answer 10

periphery of spinal cord

• made up of nerve fibers (axons).
• organized into specific ascending (sensory) and descending (motor) tracts.

Question 11

Answer 11

Question 12

Spinal nerves carry autonomic and somatic motor nerve fibers: (2)

Spinal nerves carry sensory nerve fibers (2)

Answer 12

• carry autonomic and somatic motor (general visceral efferent [GVE] and general somatic efferent [GSE])
• sensory (general visceral afferent [GVA] and general somatic afferent [GSA]) nerve fibers.

Question 13

Thirty-one paired spinal nerves exit the vertebral column through

Answer 13

Thirty-one paired spinal nerves exit the vertebral column through the intervertebral foramina or sacral foramina at each vertebral level (8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal).

Question 14

Anterior motor root carries

Answer 14

• General Somatic Efferent (GSE): motor to skeletal muscles (somatic)
• General Visceral Efferent (GVE): motor to viscera (visceral)

Carries motor (efferent) from anterior horn -> spinal nerve ->

Question 15

Posterior sensory root carries:

Answer 15

• Sensory (affarent) from posterior horn -> spinal ganglion -> spinal nerve
• General Sensory Afferent (GSA): discriminative touch, proprioception, and pain and temperature from the skin, joints, and muscles (somatic)
• General Visceral Afferent (GVA): sensation from the viscera (visceral)

Question 16

Anterior and posterior rootlets:

Answer 16

• arise from the spinal cord laterally, representing motor and sensory fibers, respectively
• Rootlets converge to form nerve roots, which contain autonomic and somatic motor (anterior root) or sensory (posterior root) components.

Question 17

Anterior vs. posterior rami

Answer 17

Once the spinal nerve has exited the vertebral column, it splits into an anterior and a posterior ramus.

• Anterior rami provide motor and sensory innervation to the skin, muscles, vasculature, and joints of the trunk and extremities
• posterior rami innervate intrinsic back muscles, associated vasculature, and overlying skin.

Question 18

ganglion

Answer 18

ganglion is a group of neuron cell bodies in the periphery to the CNS.

Question 19

Efferent

Answer 19

Motor

Soma in gray matter, axon extends along ventral root to eventually a spinal nerve

-multipolar neuron

(2 kinds: Voluntary (PNS) or autonomic (ANS))

Question 20

Affarent

Answer 20

Sensory

Pseudounipolar neuron

Soma in middle at dorsal root ganglion

(2 kinds: visceral or somatic)

Question 21

Dorsal root/Ventral root carry

Answer 21

Each only carry one type of modality

• dorsal root = sensory (affarent)
• ventral root - efferent (motor)

Question 22

Spinal nerve

Answer 22

where mixed rami (dorsal and ventral) mix