SPINAL CORD AND SPINAL NERVES

Question 1

Dura mater (cranial meninges)

Answer 1

-tough, outermost layer made of dense connective tissue
-adheres to the skull

Question 2

Arachnoid mater (cranial meninges)

Answer 2

-middle layer
-thin and translucent
-spiderweb like appearance
-contains no blood vessels or nerves, but has connective tissue projections that attaches to the pia mater

Question 3

Pia mater (cranial meninges)

Answer 3

-delicate, innermost layer
-made of a single layer of cells, and blood vessels branch out from the subarachnoid space through the pia mater into the brain providing nutrients

Question 4

Spinal cord

Answer 4

-nervous system structure that extends through the vertebral column
-part of the CNS
Functions:
-carries sensory input up the cord
-carries motor output down the cord
-involved in important spinal reflexes

Question 5

Cauda equina

Answer 5

-lower root of the lower spinal nerves

Question 6

Conus Medullaris

Answer 6

-terminal end of the spinal cord
-between L1 & L2

Question 7

Spinal meninges

Answer 7

-surround the cord
-continuation of the cranial meninges

Question 8

Dura mater (spinal meninges)

Answer 8

-outer protective layer
-though fibrous membrane sac that encloses the entire spinal cord
-thickest providing the most protection to the spine

Question 9

Arachnoid mater (spinal meninges)

Answer 9

-middle layer
-not always there
-thin web like layer
-against the dura mater

Question 10

Pia mater (spinal meninges)

Answer 10

-thin region up against the spinal cord
-inner layer
-supplies nutrients to the cord

Question 11

Spaces formed between the meninges

Answer 11

-epidural
-subdural
-subarachnoid

Question 12

Epidural space

Answer 12

-outside the dura matter
-an anesthetic is injected into the epidural space numbing the lower half of the body

Question 13

Subdural space

Answer 13

-between dura and arachnoid mater

Question 14

Subarachnoid space

Answer 14

-between pia mater (cord) and arachnoid mater
-where CSF circulates

Question 15

Gray matter

Answer 15

-brain and spinal cord is formed by neuronal cell bodies and dendrites (no myelin)

Question 16

Anterior horns

Answer 16

-cell bodies and dendrites of somatic motor neurons

Question 17

Posterior horns

Answer 17

-somatic and autonomic sensory cell bodies

Question 18

White mater

Answer 18

-formed by aggregations of myelinated axons from many neurons
-lipid part of myelin imparts white
appearance

Question 19

Sensory pathways

Answer 19

-from sensory receptors to the brain
-ascending pathways

Question 20

Primary neurons

Answer 20

-first neuron
-cell body in posterior root ganglion of spinal nerve
-extends to secondary

Question 21

Secondary neurons

Answer 21

-second neuron
-interneuron between primary and tertiary

Question 22

Tertiary neurons

Answer 22

-interneuron between secondary and cerebrum

Question 23

Posterior funiculus-medial lemniscal pathway

Answer 23

-sensory tracts (afferent)
-conveys nerve impulses for discriminative touch, light pressure, vibration, and conscious proprioception

Question 24

Anterolateral pathway

Answer 24

-sensory neuron (afferent) of spinothalamic tracts
-detect crude touch and pressure, pain and temperature, itch, tickling

Question 25

Spinothalamic tracts

Answer 25

-sensory neuron (afferent) -carry signal for proprioception to the cerebellum

Question 26

Motor pathways

Answer 26

-from brain to effectors -descending pathways

Question 27

Upper motor neurons

Answer 27

-connect the brain to the appropriate level in spinal cord

Question 28

Lower motor neurons

Answer 28

-take the information from upper motor neuron to effector -performs movement -descend to innervate skeletal muscles

Question 29

Spinal reflexes

Answer 29

-integration of information takes place in the spinal cord, not the brain

Question 30

Reflex arc

Answer 30

-pathway that a nerve impulse follows to produce a reflex -includes a sensory receptor, sensory neuron, an integrating center in the spinal cord, an exiting motor neuron and an effector

Question 31

Monosynaptic

Answer 31

-1 synapse -only a sensory and motor neuron -no interneuron

Question 32

Polysynaptic

Answer 32

-more than one synapse -includes interneurons -has one or more interneurons between the sensory and motor neuron

Question 33

Stretch reflex

Answer 33

-causes contraction of a skeletal muscle -protects from over stretching -monosynaptic reflex arc

Question 34

Tendon reflex

Answer 34

-causes muscle relaxation -controls muscle tension -prevents muscles from tearing -polysynaptic reflex arc

Question 35

Flexor reflex

Answer 35

-causes muscles to contract to withdraw a body part from a painful stimulus

Question 36

Crossed-extensor reflex

Answer 36

-maintain balance -polysynaptic -occurs in conjugation with withdrawal reflex -when withdrawal reflex is happening in one limb the crossed extensor reflex is occurring in the other limb

Question 37

There are 31 pairs of spinal nerves

Answer 37

-8 cervical, C1-C8 -12 thoracic, T1-T12 -5 lumbar, L1-L5 -5 sacral, S1-S5 -1 coccygeal

Question 38

Roots

Answer 38

-2 bundles of axons connect the spinal nerve to the cord by rootlets -short branches of spinal nerves -1 motor and sensory -motor=anterior -sensory=posterior

Question 39

Rootlets

Answer 39

-connect spinal cord to roots

Question 40

Dermatomes

Answer 40

-area of skin that is innervated by a single spinal nerve -indicated by the letter and number of a segmental nerve -important dermatomes: -C6/C7- thumb and index finger -T4- nipple line -T10- umbilicus -L1-L5- lower extremities

Question 41

Spinal nerves divide into branches known as peripheral nerves

Answer 41

-each nerve extends through the intervertebral column -splits into 2 branches: -consists of anterior and posterior rami

Question 42

Posterior ramus

Answer 42

-innervates deep muscles and skin of back

Question 43

Anterior ramus

Answer 43

-splits into multiple other branches -innervates skin and skeletal muscle of the anterior and lateral portions of the trunk, upper limbs and lower limbs