Spinal Cord And Spinal Nerves, Pathways And Intergrative Functions, Autonomic Nervous System

Front 1

What are the functions of spinal nerves?

Back 1

• Pathway for sensory and motor impulses
• Responsible for reflexes

Front 2

Where would you find: cell bodies of somatic motor neurons?

Back 2

Anterior horn of spinal cord

Front 3

Where would you find: cell bodies of autonomic motor neurons?

Back 3

Anterior horn of spinal cord

Front 4

Where would you find: terminal axons of sensory neurons and cell bodies of interneurons?

Back 4

Posterior horn of spinal cord

Front 5

Where would you find: unmyelinated axons that communicate between the left and right spinal cord?

Back 5

Gray commissure

Front 6

Draw a cross section of the spinal cord. Label the following: grey and white matter, anterior and posterior roots, dorsal root ganglia, sensory and motor neurons (cells bodies and axons).

Back 6

Front 7

Define a reflex and reflex arc.

Back 7

• Reflexes are rapid, automatic involuntary reactions of muscle or glands to a stimulus
• Reflex arc is the neural “wiring” of a single reflex. It always begins at a receptor in the PNS, communicates with the CNS, and ends at a peripheral effector, such as a muscle or gland cell.

Front 8

Is a reflex arc monosynaptic or polysynaptic?

Back 8

Monosynaptic

Front 9

Be able to define and apply the terms: monosynaptic,

Back 9

sensory axon synapse directly on the motor neurons, whose axons project to the effector: no interneurons are involves= quick respond. E.i. knee

Front 10

Be able to define and apply the terms: polysynaptic,

Back 10

are more complex neural pathways that exhibit a number of synapses involving interneurons within the reflex arc: more components=slower respond time. E.i. foot is in pain, other muscles active to “catch you”

Front 11

Be able to define and apply the terms: ipsilateral,

Back 11

when both the receptor and effector organs of the reflex are on the same side of the spinal cord. E.i. when your left arm muscle pulls out your left had from the fire

Front 12

Be able to define and apply the terms: contralateral,

Back 12

when the sensory impulses from a receptor organ cross over through the spinal cord to activate effector organs in the opposite limb. E.i. step on a tact with left foot. You jump and right leg catches you.

Front 13

Be able to define and apply the terms: Ascending and descending.

Back 13

In the direction of the spinal cords “highway”

Front 14

Are somatosensory pathways ascending or descending?

Back 14

Ascending

Front 15

Are somatosensory pathways ascending or descending?:

Do their pathways decussate?

Back 15

Yes

Front 16

Where do motor pathways originate?

Back 16

Cerebral cortex and brainstem

Front 17

From the spinal cord to the muscle: How many neurons make up a somatic motor pathway?

Back 17

2

Front 18

Where do descending motor pathways most commonly decussate?

Back 18

Pyramids in the medulla oblongata

Front 19

Compare and contrast the autonomic and somatic nervous system.

Back 19

Autonomic Nervous System actives the involuntary actions

Somatic Nervous System actives voluntary actions

Front 20

Draw the (general) 2 neuron chain of the ANS and label the pre- and postganglionic cells and axons, spinal cord, autonomic ganglion, preganglion neuron is mylenated, the noy postganlion neuron and an effector organ.

Back 20

Front 21

What are the functions of the Sympathetic and Parasympathetic divisions of the ANS?

Back 21

Sympathetic – flight or fight

Parasympathetic – rest or digest

Front 22

From which region of the spinal cord, approximately, does each originate?

Back 22

Sympathetic - T1 to L2

Parasympatheric - brainstem and sacrum 2 to sacrum 4

Front 23

What are the anatomic differences between the organization of parasympathetic and sympathetic neurons?

Back 23

The preganglionic axon of the sympathetic neuron is short but branched, the postganglionic axon is long so the autonomic ganglion is farther to the effector.


The preganglionic axon in the parasympathetic neuron is longer but not branched, the postganglionic axon is shorter so the autonomic ganglion is closer to the effectro.

Front 24

What is the significance of the paravertebral ganglia?

Back 24

House sympathetic ganglionic neuron cell bodies

Front 25

How do they contribute to convergence and divergence?

Back 25

–each postganglionic cell may receive synapses from multiple preganglionic cells: neuronal convergence

– each preganglionic fiber branches and synapses with multiple postganglionic fibers: neuronal divergence