Ch. 12

Question 1

Spinal cord

Answer 1

the major communication link between the brain and the PNS inferior to the head. Integrates incoming info and produces responses

Question 2

Spinal nerves

Answer 2

Exit the vertebral column through intervertebral and sacral foramina. Each spinal cord is a bundle of axons, schwann cells and connective tissue sheath.

31 pairs

Question 3

Cervical enlargement

Answer 3

Location where nerve fibers that supply upper limbs enter and leave the spinal cord

Question 4

Lumbosacral enlargement

Answer 4

in inferior thoracic, lumbar, and superior sacral regions where nerve fibers supplying lower limbs enter or leave the spinal cord.

Question 5

Conus medullaris

Answer 5

Cone-like region where spinal cord tappers, inferior to the lumbosacral enlargement

Question 6

Cauda equina

Answer 6

The numerous roots of spinal nevers extending inferiorly from the lumbosacral enlargement and conus medullaris

Question 7

Meninges

Answer 7

Connective tissue membranes that surround spinal cord and brain

Question 8

Dura mater

Answer 8

Most superficial and thickest membrane in the meninge of spinal cord. Forms a sac called Thecal sac, which surrounds spinal cord

Question 9

Epidural space

Answer 9

Space between the walls of the vertebral canal and dura mater of the spinal cord that contains spinal nerve roots, blood vessels, areolar connective tissue and adipose tissue

Question 10

Epidural anesthesia

Answer 10

often administered to woman in childbirth by injecting anesthetics into the epidural space of the spinal cord

Question 11

Arachnoid

Answer 11

2nd deepest meningeal membrane. Very thin and wispy

Question 12

Subdural space

Answer 12

The space between arachnoid mater and the dura mater. Contains a very small amount of serous fluid

Question 13

Pia Mater

Answer 13

The 3rd deepest meningeal layer. Bound very tightly to the surface of the spinal cord

Question 14

Denticulate ligaments

Answer 14

Connective tissue septa extending from the lateral sides of the spinal cord to the dura mater

Question 15

Filum terminale

Answer 15

connective tissue strand that anchors the conus medullaris and the thecal sac to the first coccygeal vertebra, limiting their superior movement

Question 16

Subarachnoid space

Answer 16

Contains web-like strands of the arachnoid mater, blood vessels and cerebrospinal fluid

Question 17

Anterior median fissure & posterior median sulcus

Answer 17

deep clefts partially separating the 2 halves of the cord

Question 18

What are the 3 columns or funiculi in each half of the spinal cord?

Answer 18

Ventral (anterior)
Dorsal (Posterior)
Lateral columns

Question 19

Each column of the spinal cord is subdivided into …

Answer 19

Tracts or fasicles

Question 20

The central gray matter is organized into what horns?

Answer 20

Dorsal horn
Ventral horn
Small lateral horns

Question 21

What are gray and white commissures?

Answer 21

Contain axons that cross from one side of teh spinal cord to the other

Question 22

What is the central canal?

Answer 22

located in center of the gray commissure, helps circulate CSF associated with the ventricular system

Question 23

Ventral root

Answer 23

6-8 rootlets combined on the ventral side of spinal cord

Question 24

Dorsal root

Answer 24

6-8 rootlets combined on the dorsal side of the spinal cord

Question 25

Dorsal root ganglion?

Answer 25

where Sensory neuron cell bodies are contained

Question 26

What is a reflex?

Answer 26

automatic response to a stimulus. Occurs without conscious thought

Question 27

What is a reflex arc?

Answer 27

The neural pathway that controls a reflex

Question 28

Monosynaptic reflexes

Answer 28

involve simple neuronal pathways in which sensory neurons synapse directly with motor neurons without any interneurons

Question 29

Polysynaptic reflexes

Answer 29

involve more complex pathways that have multiple synapses with interneurons between the sensory and motor neurons

Question 30

What is the stretch reflex?

Answer 30

The simplest reflex. A reflex contraction of muscles in response to stretching of that same muscle

Question 31

Muscle spindle

Answer 31

The sensory receptor of the stretch reflex. 3-10 small specialized skeletal muscle fibers that are contractile only at their ends

Question 32

Alpha motor neuron

Answer 32

Causes the muscle to contract*

Question 33

Knee-jerk reflex

Answer 33

When the doctor taps on the patellar ligament and your knee kicks

Question 34

Gamma motor neurons

Answer 34

Innervate the ends of the muscle spindles

Question 35

Golgi tendon reflex

Answer 35

Prevents contracting muscles from applying excessive tension to tendons

Question 36

Golgi tendon organs

Answer 36

The sensory receptors for the golgi tendon reflex

Question 37

What is the withdrawal reflex?

Answer 37

To remove a limb or another body part from a painful stimulus

Question 38

Reciprocal innervation

Answer 38

a phenomenon that allows opposing muscles to reinforce the efficiency of the withdrawal reflex

Question 39

Crossed extensor reflex

Answer 39

Another reflex associated with withdrawal reflex. Occurs on opposite side of the body from the stimulus

Question 40

Endoneurium

Answer 40

delicate connective tissue layer that surrounds each axon, or nerve fiber

Question 41

Perineurium

Answer 41

Heavier connective tissue layer that surrounds groups of axons to form nerve fascicles

Question 42

Epineurium

Answer 42

3rd layer of dense connective tissue that binds the nerve fascicles together to form a nerve

Question 43

Ramus

Answer 43

A major branch of a spinal cord

Question 44

Dermatome

Answer 44

is the area of the skin supplied with sensory innervation by a pair of spinal nerves

Question 45

What is a dorsal rami

Answer 45

innervates most of the deep muscles of the dorsal trunk responsible for moving the vertebral column

Question 46

Ventral rami

Answer 46

In the thoracic region, form intercoastal nerves which extend along the inferior margin of each rib and innervate the intercoastal muscles and skin over thorax

Question 47

PLexus

Answer 47

intermingling of nerves

Question 48

What is the cervical plexus?

Answer 48

relatively small plexus originating from spinal nerves C1-C4

Question 49

Ansa cervicalis

Answer 49

unusual part of the cervical plexus, a loop between C1 and C3. Nerves to the infrahyoid muscles branch from ansa cervialis

Question 50

Phrenic nerve

Answer 50

One of the most important derivatives of the cervical plexus. Important for breathing

Question 51

Brachial plexus

Answer 51

Originates from spinal nerves C5-T1

Question 52

Axillary nerve

Answer 52

Innervates the deltoid and teres minor muscles. Provides sensory innervation to the shoulder joint and to the skin over part of the shoulder

Question 53

Radial nerve

Answer 53

Innervates all of the extensor muscles of the upper limb, the supinator muscle and the brachioradialis

Question 54

Musculocutaneous nerve

Answer 54

provides most motor innervation to the anterior muscles of the arm, as well as cutaneous sensory innervation to part of forearm

Question 55

Ulnar nerve

Answer 55

Innervates 2 forearm muscles plus most of the intrinsic hand muscles