chapter 13, spinal cord

Question 1

What is the spinal cord?

Answer 1

The cylindrical nervous tissue that extends from the brainstem and transmits neural signals between the brain and body.

Question 2

What is the cervical enlargement?

Answer 2

A widened section of the spinal cord supplying nerves to the upper limbs.

Question 3

What is the lumbar enlargement?

Answer 3

A widened section supplying nerves to the lower limbs.

Question 4

What is the medullary cone (conus medullaris)?

Answer 4

The tapered end of the spinal cord, located around L1-L2.

Question 5

What is the cauda equina?

Answer 5

A bundle of nerve roots extending beyond the spinal cord.

Question 6

What are meninges?

Answer 6

Protective layers surrounding the spinal cord and brain.

Question 7

What is the dura mater?

Answer 7

The tough outermost layer of the meninges.

Question 8

What is the arachnoid mater?

Answer 8

The middle layer containing cerebrospinal fluid (CSF).

Question 9

What is the pia mater?

Answer 9

The delicate inner layer adhering to the spinal cord.

Question 10

What is the epidural space?

Answer 10

The space between the dura mater and the vertebrae, containing fat and blood vessels.

Question 11

What is the subarachnoid space?

Answer 11

The space between the arachnoid and pia mater, filled with CSF.

Question 12

What is gray matter?

Answer 12

The region containing neuron cell bodies and synapses.

Question 13

What does the dorsal (posterior) horn contain?

Answer 13

Contains sensory neuron synapses.

Question 14

What does the ventral (anterior) horn contain?

Answer 14

Contains motor neuron cell bodies.

Question 15

What is the lateral horn?

Answer 15

Found in thoracic and upper lumbar regions, contains autonomic motor neurons.

Question 16

What is white matter?

Answer 16

Myelinated axons that form tracts to and from the brain.

Question 17

What are ascending tracts?

Answer 17

Sensory pathways that carry signals to the brain.

Question 18

What are descending tracts?

Answer 18

Motor pathways that carry signals from the brain to muscles.

Question 19

What is decussation?

Answer 19

The crossing over of nerve fibers from one side of the body to the other.

Question 20

What does the spinothalamic tract transmit?

Answer 20

Transmits pain, temperature, and crude touch.

Question 21

What does the dorsal column-medial lemniscus (DCML) pathway transmit?

Answer 21

Transmits fine touch, vibration, and proprioception.

Question 22

What does the spinocerebellar tract transmit?

Answer 22

Transmits unconscious proprioception to the cerebellum.

Question 23

What is the corticospinal tract?

Answer 23

The primary motor pathway for voluntary movements.

Question 24

What does the tectospinal tract control?

Answer 24

Controls reflexive movements of the head in response to stimuli.

Question 25

What is the role of the reticulospinal tract?

Answer 25

Helps regulate muscle tone and posture.

Question 26

How many pairs of spinal nerves are there?

Answer 26

31 pairs of nerves that carry motor, sensory, and autonomic signals between the spinal cord and the body.

Question 27

What does the dorsal root carry?

Answer 27

Carries sensory information to the spinal cord.

Question 28

What is the dorsal root ganglion?

Answer 28

A cluster of sensory neuron cell bodies.

Question 29

What does the ventral root carry?

Answer 29

Carries motor signals from the spinal cord.

Question 30

What are mixed nerves?

Answer 30

Contain both sensory and motor fibers.

Question 31

What is the cervical plexus (C1-C5)?

Answer 31

Innervates the neck and diaphragm (includes the phrenic nerve).

Question 32

What does the brachial plexus (C5-T1) innervate?

Answer 32

Innervates the upper limb.

Question 33

What does the lumbar plexus (L1-L4) innervate?

Answer 33

Innervates the lower limb and abdominal wall.

Question 34

What does the sacral plexus (L4-S4) innervate?

Answer 34

Innervates the buttocks, lower limb, and pelvic structures.

Question 35

What is the coccygeal plexus (S4-Co1)?

Answer 35

Small network of nerves near the coccyx.

Question 36

What is a reflex?

Answer 36

A rapid, automatic response to a stimulus.

Question 37

What is a reflex arc?

Answer 37

The neural pathway involved in a reflex action.

Question 38

What detects the stimulus in a reflex arc?

Answer 38

Receptor.

Question 39

What carries the signal to the CNS in a reflex arc?

Answer 39

Afferent (sensory) neuron.

Question 40

What processes information in the spinal cord or brainstem?

Answer 40

Integration center.

Question 41

What carries the signal to an effector in a reflex arc?

Answer 41

Efferent (motor) neuron.

Question 42

What is an effector?

Answer 42

The muscle or gland that responds.

Question 43

What are somatic reflexes?

Answer 43

Involve skeletal muscles (e.g., patellar reflex).

Question 44

What are autonomic reflexes?

Answer 44

Involve smooth muscle, glands, or cardiac muscle (e.g., pupillary reflex).

Question 45

What is a monosynaptic reflex?

Answer 45

A reflex involving only one synapse (e.g., stretch reflex).

Question 46

What is a polysynaptic reflex?

Answer 46

A reflex involving multiple synapses (e.g., withdrawal reflex).

Question 47

What is an ipsilateral reflex?

Answer 47

The response occurs on the same side as the stimulus.

Question 48

What is a contralateral reflex?

Answer 48

The response occurs on the opposite side of the stimulus.

Question 49

What does the stretch reflex maintain?

Answer 49

Maintains muscle tone and posture (e.g., patellar knee-jerk reflex).

Question 50

What does the withdrawal (flexor) reflex cause?

Answer 50

Causes a limb to withdraw from pain.

Question 51

What does the crossed extensor reflex help maintain?

Answer 51

Helps maintain balance when withdrawing from a stimulus.

Question 52

What does the tendon reflex prevent?

Answer 52

Prevents muscle damage from excessive tension.

Question 53

What is spinal cord injury (SCI)?

Answer 53

Damage to the spinal cord causing loss of function.

Question 54

What is paralysis?

Answer 54

Loss of motor function due to spinal cord damage.

Question 55

What is paresthesia?

Answer 55

Abnormal sensation (e.g., tingling, numbness) due to nerve injury.

Question 56

What is quadriplegia?

Answer 56

Paralysis of all four limbs (cervical spinal cord injury).

Question 57

What is paraplegia?

Answer 57

Paralysis of the lower limbs (injury below the cervical region).

Question 58

What is spina bifida?

Answer 58

A birth defect where the spinal column does not close properly.

Question 59

What is amyotrophic lateral sclerosis (ALS)?

Answer 59

A neurodegenerative disease affecting motor neurons.