Chapter 12 - Spinal cord, meninges, tissue

Question 1

Conus medullaris

Answer 1

Tapered inferior end of spinal cord

Question 2

Cauda equina

Answer 2

Origins of spinal nerves extending inferiorly from lumbosacral enlargement and conus medullaris

Question 3

Layers of meninges (superficial to deep)

Answer 3

-Dura mater
-Arachnoid mater
-Pia mater

Question 4

Dura mater

Answer 4

-Layer of CT around spinal cord
-Continuous with the epineurium of spinal nerves
-Most superficial layer

Question 5

Arachnoid mater

Answer 5

-Layer of CT around spinal cord
-Thin and wispy
-Middle layer

Question 6

Pia mater

Answer 6

-Layer of CT around spinal cord
-Bound tightly to surface of brain and spinal cord
-Deepest layer

Question 7

Epidural space

Answer 7

-Space between periosteum and dura mater
-Contains blood vessels, areolar CT, and fat

Question 8

Subdural space

Answer 8

-Space between dura mater and arachnoid mater
-Contains serous fluid

Question 9

Subarachnoid space

Answer 9

-Space between arachnoid mater and pia mater
-Contains CSF and blood vessels within web-like strands of arachnoid tissue

Question 10

Commissures

Answer 10

Connections between left and right halves of the spinal cord

Question 11

Roots

Answer 11

-Spinal nerves arise as rootlets, then combine to form roots
-Dorsal and ventral root that merge laterally to form a spinal nerve
-Dorsal root has a ganglion

Question 12

Components of the reflex arc

Answer 12

-Sensory receptor
-Sensory neuron
-Interneuron
-Motor neuron
-Effector organ

Question 13

Stretch reflex

Answer 13

-Muscles contract in response to a stretching force applied to them
-No interneuron

Question 14

Golgi tendon reflex

Answer 14

-Prevents contracting muscles from applying excessive tension to tendons
-Prevents damage to tendons
-Produces sudden relaxation of muscles

Question 15

Withdrawal reflex

Answer 15

-Removes a body part from a painful stimulus
-Reciprocal innervation

Question 16

Reciprocal innervation

Answer 16

-Causes relaxation of extensor muscle when flexor muscle contracts
-Involved in stretch and withdrawal reflexes

Question 17

Endoneurium

Answer 17

Layer of CT that surrounds individual neurons

Question 18

Perineurium

Answer 18

Layer of CT that surrounds axon groups to form fasicles

Question 19

Epineurium

Answer 19

Layer of CT that surrounds the entire nerve

Question 20

Dorsal ramus

Answer 20

Innervates deep muscles of the trunk responsible for movements of the vertebral column, and CT/skin near the midline of the back

Question 21

Ventral ramus

Answer 21

What they innervate depends on which part of the spinal cord is being considered

Question 22

Cervical plexus

Answer 22

-C1-C4
-Innervates superficial neck structures, skin of neck, posterior portion of head
-Ansa cervicalis
-Phrenic nerve

Question 23

Phrenic nerve

Answer 23

-In cervical and brachial plexuses
-C3-C5
-Innervates diaphragm

Question 24

Brachial plexus

Answer 24

-C5-T1
-5 ventral rami form 3 trunks that split into 6 divisions that form cords that give rise to 5 nerves
-Branches: Axillary, radial, musculocutaneous, ulnar, median, etc

Question 25

Axillary nerve

Answer 25

-Originates from posterior cord of brachial plexus (C5-C6) -Laterally rotates arm (teres minor) -Abducts arm (deltoid) -Cutaneously innervates inferior lateral shoulder

Question 26

Median nerve

Answer 26

-Originates from median and lateral cords of brachial plexus (C5-T1) -Pronates forearm and hand (pronator teres/quadratus) -Flexes (palmaris longus) and abducts wrist (flexor carpi radialis) -Flexes fingers -Controls thumb muscle -Controls thenar muscles -Flexes metacarpophalangeal joints, extends interphalangeal joints -Cutaneously innervates lateral 2/3s of hand

Question 27

Lumbar and sacral plexuses

Answer 27

-Lumbar: Ventral rami of L1-L4 -Sacral: Ventral rami of L4-S4 -Branches: Obturator, femoral, tibial, common fibular (peroneal)

Question 28

Coccygeal plexus

Answer 28

-S5 -Coccygeal nerve -Sensory info from skin over coccyx

Question 29

Ansa cervicalis

Answer 29

Loop between C1 and C3