The Spinal Cord, Spinal Nerves, And Spinal Reflexes

Front 1

What are spinal reflexes?

Back 1

Spinal reflexes are quick, automatic responses triggered by specific stimuli. Spinal reflexes are controlled in the spinal cord.

They can function without any input from the brain. For example, a reflex controlled in the spinal cord makes you drop a frying pan you didn't realize was sizzling hot.

Front 2

Study the following image.

Back 2

Front 3

What is the difference, function-wise, of the dorsal root and the ventral root?

Back 3

The dorsal roots brings sensory information into the spinal cord.

The ventral roots contains the axons of motor neurons that extend into periphery to control somatic and visceral effectors.

Front 4

What is the spinal nerve?

Back 4

Spinal nerves are classified as mixed nerves-that is, they contain both afferent (sensory) and efferent (motor) fibers.

Front 5

What is the spinal meninges?

Back 5

The spinal meninges are a series of specialized membranes surrounding the spinal cord, provide the necessary physical stability and shock absorption. Blood vessel branching with these layers deliver oxygen and nutrients to the spinal cord.

Front 6

What is the dura mater?

Back 6

The tough fibrous dura mater is the layer that forms the outermost covering of the spinal cord. This layer contains dense collagen fibers that are oriented along the longitudinal axis of the cord.

Front 7

What is the arachnoid mater?

Back 7

The arachnoid mater is the middle meningeal layer.

Between the arachnoid membrane and the arachnoid trabecular is the subarachnoid space which acts as a shock absorber and a diffusion medium for dissolved gases, nutrients, chemical messengers, and wastes.

Front 8

What is the pia mater?

Back 8

The pia mater is the innermost meningeal layer.

Front 9

______ matter ingrates information and initiates commands, and ________ matter carries information from place to place .

Back 9

1) Gray

2) White

Front 10

What does gray matter surround?

Back 10

The narrow central canal.

Front 11

What nuclei do the posterior gray horns contain?

Back 11

They contain the somatic and visceral sensory nuclei.

Front 12

What nuclei do the anterior gray horns contain?

Back 12

They contain somatic motor nuclei.

Front 13

What nuclei do the lateral gray horns contain?

Back 13

Thy contain visceral motor nuclei.

Front 14

The white matter on each side of the spinal cord can be divided into three regions called? Identify are the three regions.

Back 14

They are divided into three regions called columns.

- Posterior White Columns

- Anterior White Columns

- Lateral White Columns

Front 15

What is another name for columns?

Back 15

Funiculi

Front 16

What are tracts?

Back 16

A tract, or a fasiculu, is a bundle of axons in the CNS that is somewhat uniform in diameter, myelination, and propagation speed. All the axons within a tract relay the same type of information (sensory or motor) in the same direction.

Front 17

What kind of information does the ascending tracts carry?

Back 17

Ascending tracts carry sensory information toward the brain

Front 18

What kind of information does the descending tracts carry?

Back 18

The descending tracts convey motor commands to the spinal cord.

Front 19

What is peripheral neuropathies?

Back 19

Peripheral nerve palsies are regional losses of sensory and motor function most often resulting from nerve trauma or compression.

If your arm or leg has ever fallen asleep, you have experienced a mild, temporary palsy.

Front 20

The cervical plexus consists of ventral rami of spinal nerves:

Back 20

C1-C5

Front 21

The brachial plexus innervates the pectoral girdle and upper limb, with contributions from the ventral rami and spinal nerves:

Back 21

C5 - T1

Front 22

What is divergence?

Back 22

A mechanism for spreading stimulation to multiple neurons or neuronal pools in the CNS.

Front 23

What is convergence?

Back 23

A mechanism for providing to a single neuron from multiple sources.

Front 24

What is serial processing?

Back 24

A mechanism in which neurons or pools work sequentially.

Front 25

What is parallel processing?

Back 25

A mechanism in which neurons or pools process the same information simultaneously

Front 26

What is reverberation?

Back 26

A positive feedback mechanism

Front 27

What are neuronal pools?

Back 27

They are functional groups of interconnected neurons. A neuronal pool may be scattered, involving neurons in several regions of the brain, or localized, with neurons restricted to one specific location in the brain or spinal cord.

Front 28

What are reflexes?

Back 28

Reflexes are rapid, automatic responses to specific stimuli. Reflexes preserve homeostasis by making rapid adjustments in the function of organs or organ systems.

Front 29

What is a reflex arc?

Back 29

The "wiring" of a single reflex is called a reflex arc. It begins at a receptor and ends at a peripheral effector such as a muscle fiber or a gland cell.

Front 30

What is a stretch reflex?

Back 30

A stretch reflex is an example of a monosynaptic reflex. Because there is only one synapse, there is little delay between sensory input and motor output.

The patellar reflex is an example of stretch reflex. The stimulus is a tap on the patellar tendon that stretches receptors within the quadriceps muscles. The response is a brief contraction of those muscles which produces a noticeable kick

Front 31

What is withdrawal reflex?

Back 31

A withdrawal reflex moves affected parts of the body away from a stimulus. A flex reflex is an example of a withdrawal reflex, that affects the muscles of a limb. In this example the stimulus of a hot frying pan causes the contraction of the flexor muscles of the arm, yanking the forearm and hand away from the pan.

Front 32

What is crossed extensor reflex?

Back 32

A crossed extensor reflex involves a contralateral reflex arc. In other words, a motor response to the stimulus also occurs on a side opposite the stimulus. The crossed extensor reflex complements the flexor reflex, and the two occurs simultaneously. When you step on a tack, the flexor reflex pulls the affected foot away from the ground, while the crossed extensor reflex straightens the other leg to support your body weight.

Front 33

What are innate reflexes?

Back 33

They results from the connections that form between neurons during development. Such reflexes generally appear in predictable sequence, from the simplest reflex responses (withdrawal from pain) to more complex motor patterns (chewing, suckling, or tracking objects with the eyes)

Front 34

What are acquired reflexes?

Back 34

They are more complex, learned motor patterns.

Front 35

What are somatic reflexes?

Back 35

Somatic reflexes provide a mechanism for the involuntary control of the muscular system.

Front 36

What are visceral reflexes?

Back 36

Visceral reflexes are autonomic reflexes that control the activities of other systems.

Front 37

What are postural reflexes?

Back 37

Postural reflexes help us maintain a normal upright posture.