Anatomy Exam 4. Ch.12 Nervous System Spinal Cord

Front 1

1.What is the function of the spinal cord?

Back 1

-Major communication link between the brain and the PNS inferior to the head.
-Participates in the integration of incoming information
-Produces responses thru reflex mechanisms
-Gives rise to 31 pairs of spinal nerves

Front 2

2.What skeletal structure do spinal nerves pass through?

Back 2

-Intervertebral foramen

Front 3

3.What is the conus medullaris?

Back 3

tapered inferior end of spinal cord

Front 4

-Cauda equina

Back 4

roots and nerves extending down vertebral canal below l2

Front 5

-Filum terminale

Back 5

delicate strand of fibrious tissue~ 20cm in length, proceeding downward from apex of conus medullaris

Front 6

4.What function does the filum terminale perform?

Back 6

-Provides longitudinal support
-Protection of spinal cord

Front 7

5.Why are the inferior roots elongated to form the cauda equina

Back 7

-Collection of nerves in vertebral column that continue to travel through the vertebral column below conus medullaris
- Forms as a result of the of fact that the spinal cord stops growing in length at about age 4 even though the vertebral column continues to lengthen until adulthood

Front 8

6.How long is the spinal cord in relationship to the vertebral cavity?

Back 8

-Extend from foramen magnum – L2
-It is shorter than vertebral cavity because the Spinal cord stops growing in length by age 4

Front 9

7.Describe how the anatomy of the spine, spinal cord, and meninges relate to our ability to perform spinal taps/lumbar punctures

Back 9

Needle inserted into subarachnoid space inferior to level of second lumbar vertebrae.
-needle intro into either l3-l5 intervertebral space
Needle doesn’t contact spinal cord because it extends only to 2nd lumbar vertebra of vertebral column but the subarachnoid space extends to level s2 of vertebral column
- needle doesn’t damage nerve roots of cauda equina located in subarachnoid space becaue the needle quit4e easily pushes them aside.
-
-During a lumbar puncture the needle is inserted between spaces between vertebrae, base of spinous processes, body of vertebrae, interior vertebrae
-Needle inserted posteriorly from behind through all posterior ligaments
-Thru subarachnoid space
-Able to do relatively safe because no solid spinal cord for need to pass through because SC stops between conus medullaris l1-l3
-Vertebral canal continues down length of sacrum but
-Theres portion of vertebral canal not occupied by actual spinal cord= creates opportunity for spinal tap/lumbar puncture
-Roots pushed out of way by needle

Front 10

8.Describe the structure and function of the spinal meninges and associated spaces

Back 10

connected tissue membranes surrounding spinal cord and brain

Front 11

- Epidural Space

Back 11

contains blood vessels, areolar CT and fat

Front 12

- Dura Mater

Back 12

continuous with epineurium of the spinal nerves
Substances can leak into space, not fused together
No real space b/t in normal noninjured person no subdural space
Superficial and thickest membrane outermost

Front 13

- Arachnoid Mater:

Back 13

: thin and wispy, thin fibers extend ffrom arachnioid to pia form spider web

Front 14

- Subarachnoid space

Back 14

contains CSF and blood vessels withing web-like strands of arachnoid tissue

Front 15

- Pia mater

Back 15

innermost layer on surface of sc. Structures that help stablize SC.
Filum terminale: tip of conus medullaris. Anchors tip spinal cord to coccyx-longitudinal support

Front 16

Denticulate ligaments

Back 16

attach the spinal cord to the dura mater laterally-lateral support.

Front 17

9.What fills the epidural space?

Back 17

blood vessels, areolar connective tissue, fat

Front 18

What fills the Subarachnoid space?

Back 18

CSF and blood vessels within web-like strands of arachnoid tissue

Front 19

10.List the meninges in order from most external to most internal.

Back 19

DAP
- Dura mater
- Arachnoid mater
- Pia mater

Front 20

11. What is CSF and where is it found in relation to the spinal cord?

Back 20

- CSF is fluid similar to blood serum with most protiens removed
- Found in subarachnoid space between arachnoid and pia mater
- Provides cushioning around CNS

Front 21

12. What are denticulate ligaments? What do they connect/join? What is their function?

Back 21

- Found within Pia mater holds SC in place
- Attach SC to Dura mater laterally- lateral support, limits lateral movement
- Paired septa extending from lateral sides of spinal cord to dura mater.
- Attach to dura mater by 21 triangular toothlike processes between exits of cervical and thoracic spinal nerves

Front 22

-Anterior median fissure,- posterior medial sulcus,

Back 22

-deep clefts partially separating the 2 left and right halves of the SC on outsides of white mater

Front 23

- Dorsal (posterior) horn,

Back 23

- organization of gray mater
within central gray mater ,thin part at back where sensory neurons enter cord

Front 24

- ventral (anterior) horn

Back 24

- organization of gray mater
larger half in central gray mater, front, where cell bodies of somatic motor neurons

Front 25

- lateral horn

Back 25

- organization of gray mater
small horns associated with ANS-cell bodies of visceral motor neurons in between posterior and anterior horn. -Distinct lateral horn not present in all regions of cord only in thoracic and lumbar regions

Front 26

Dorsal columns, lateral columns, ventral columns (Funiculi)

Back 26

- Organization or division of white mater
- Ea. Subdivision into tracts(fasciculi, pathways)
- Carry info to and from other regions of the SC

Front 27

Gray and white commissures:

Back 27

- Connections between left and right halveof CNS
- Contain axons that cross from one side of SC to the other

Front 28

Central Canal

Back 28

- Canal in center of gray commisure

Front 29

Dorsal root:

Back 29

- Extend laterally from SC passing through subarachnoid space
- Goes through arachnoid and dura mater and joining one another to form spinal nerve
- Formed from 6 to 8 rootlests on dorsal side of SC

Front 30

Ventral root:

Back 30

- Formed from six to eight rootlets along ventral, anterior side

Front 31

Dorsal root ganglion

Back 31

- Collections of cell bodies of sensory neurons forming the dorsal roots of the spinal nerves

Front 32

Spinal Nerve

Back 32

- Where dorsal and ventral roots meet laterally and form
- Passes through intervertebral foramen

Front 33

14.What kind neurons (both functional and structural classification) are found in the ventral root?

Back 33

- Motor nerve
- Axons of motor neurons
- Multipolar

Front 34

What kind neurons (both functional and structural classification) are found in Dorsal root?

Back 34

- Sensory nerve
- Sensory neurons
- Unipolar

Front 35

16. What kind neurons (both functional and structural classification) are found in Spinal nerve?

Back 35

- Mixed nerves
- Axons of both motor and sensory neurons

Front 36

17. What is found in the dorsal root ganglion?

Back 36

- Ganglion cell bodies of sensory neurons

Front 37

18. Where are the cell bodies of motor neurons?

Back 37

- Innervate muscles and glands
- In the anterior and lateral horns of the gray mater

Front 38

Multipolar Somatic motor neurons

Back 38

- Anterior horn

Front 39

Autonomic Visceral motor neurons

Back 39

- Lateral horn

Front 40

19. Where are the cell bodies of sensory neurons?

Back 40

- Dorsal horn- somatic and visceral sensory
- Dorsal root ganglion- unipolar sensory

Front 41

20. What root contains bipolar neurons?

Back 41

- Dorsal root ganglion
- goes to olfactory,retina,auditory

Front 42

21. What root contains multipolar neurons?

Back 42

- Ventral (anterior) root

Front 43

22. What root contains motor neurons?

Back 43

- Ventral root

Front 44

23. What root contains sensory neurons?

Back 44

- Dorsal root

Front 45

24. What is a reflex?

Back 45

- Automatic responses to specific stimuli that do not require conscious thought/processing
- Higher brain centers can influence,suppress, or exaggerate reflex responses

Front 46

Types of reflex

Back 46

 Learned. Ex repetitive actions. Brake on red light
 Innate(typically homeostatic) keep blood pressure,temp in balance and functional

Front 47

where can reflex occur

Back 47

- Cranial, integrated in brain
- Spinal,integrated in spinal cord
- Represent some of the most basic nerve pathways and CNS integration..
- Brain not necessary for spinal reflex to occur but can modify

Front 48

25.Describe a reflex arc?

Back 48

- Pathway of information through reflex
- What structures electrical info travel through from sense receptors all the way out to motor effector
- Electical impulse(action potentials) produced in 1)Sensory Receptors to
2)sensory neuron
3) motor neuron
4) effector

Front 49

26. Describe a basic monosynaptic reflex arc (pathway of impulses and locations of sensory and motor neurons) such as the knee-jerk (stretch/extensor) reflex.

Back 49

1) Stretch receptor( muscle spindle) detects stretc
2) Sensory neuron
3) synapse with motor neurons of the spinal cord
4) motor neuron innervates muscle that was stretched causing contraction

Front 50

monosynaptic

Back 50

-one synapse
- 2 neurons
- Sensory neuron synapse directly with motor neuron

Front 51

- Withdrawal/Flexor Reflex

Back 51

to provide homeostasis and prevent from harm
> function to remove a body limb or other part from a painful stimulus

Front 52

Polysynaptic:

Back 52

 2+ synapses
 3+ neurons
- - 1sensory
- - 1 motor
- - 1 interneuron: between sensory & motor neuron exists entirely w/in CNS

Front 53

- Basic Withdrawal

Back 53

 Reflex arc goes from pain receptor (free nerve endings of sensory neuron)
 Thru single sensory neuron up to peripheral nerve to spinal nerve to dorsal root, SC dorsal horn, synapse with black interneuron(excitatory) cont’d pass electrical impulse along own impulse passes on directly to purple motor neuron goes to hamstring muscles, n muscle contract causes to flex and pull blood away from sharp painful path ie. Nail

Front 54

know pathway. 2 neurons.
What does Sensory neuron travels through spinal nerve, dorsal root,
Dorsal horn. Comes out sensory neuron

Back 54

how does specific sensory input result in specific action of flexing n pulling foot away
Direct link between sensory reflex and motor output because sensory neuron meets
Interneuron that directly connects to motor neuron

Front 55

polysynaptic reflex arc
Reciprocal innervations

Back 55

- Stimulating one muscle for contraction but causes inhibits prevents other from contracting and making it relaxed.
- Causes relaxation of antagonistic extensor muscle when flexor muscle contracts.

Front 56

29. What is a nerve?

Back 56

- Bundle of axons/nerve fibers
- Surrounded by connective tissues 3 types endo,epi,peri neurium
- Schwann cells

Front 57

- Endoneurium

Back 57

 Loose CT with capillaries that supply neurons with blood
 Surrounds individual neurons

Front 58

Individual axons grouped into bundles

Back 58

Fasicles

Front 59

- Perineurium

Back 59

 Surrounds axon groups to form fascicles
 Blood vessels pass through this layer
 Dense CT

Front 60

- Epineurium

Back 60

 Surrounds the entire nerve
 Dense CT

Front 61

Spinal nerve:

Back 61

>each associated with specific region of body ie. Cutaneous sensation. >Dermatomal map.

Front 62

how are rami formed

Back 62

Every peripheral nerve external to spinal nerve. SN goes out of intervertebral foramen and branch out to become Rami

Front 63

dorsal rami

Back 63

back posterior,
>less tissue material to innervate
>smaller
>closer to SC

Front 64

ventral rami:

Back 64

larger
>more tissues and neurons to innervate

Front 65

their anatomical relationship to one another:
rami spinal nerve

Back 65

Sensory Info SC comes from dorsal or ventral rami into spinal nerve thru dorsal root into spinal cord
Motor info leaves SC out to somatic motor cells comes thru ventral root to spinal nerve out to either rami depending where going anterior or posterior.

Front 66

 Formed by ventral rami of remaining spinal nerves

Back 66

Plexuses:

Front 67

Intercostal nerves:

Back 67

 In thoracic region formed by dental rami
 Extended along infeiro margin of each rib and innervate the intercostals muscles and skin over thorax

Front 68

32. What is a plexus?
What structures create a plexus

Back 68

 Intermingling of nerves braid
 Formed by remaining spinal nerves from ventral rami.
 Roots-ventral rami of different spinal nerves join together[.
 5 plexuses

Front 69

Cervical plexus

Back 69

 C1-C4
 Innervates superficial neck structures, skin of neck, posterior portion of head

Front 70

Brachial plexus:

Back 70

 C5-T1 and some from C4
 Branches/nerves

Front 71

brachial plexus nerves/brances

Back 71

- Axillary
- Radial
- Musculocutaneous
- Ulnar
- Median

Front 72

Lumbosacral plexus:

Back 72

- Lumbar plexus:
and sacral
 Sometimes considered together because of close relationship
 Four major nerves exit and enter lower limb
- Obturator
- Femoral
- Tibial
- Common fibular (peroneal)

Front 73

Lumbar plexus:

Back 73

Ventral rami of L1-L4

Front 74

- Sacral plexus

Back 74

ventral rami of L4-S4

Front 75

The spinal cord extends from the

Back 75

medulla oblongata to the level of the second lumbar vertebra

Front 76

the structure that anchors the inferior end of the spinal cord to the coccyx

Back 76

filum terminale

Front 77

axons of sensory neurons synapse wieh the cell bodies of interneurons in the _________ of spinal cord gray matter

Back 77

posterior horn

Front 78

cell bodies for spinal sensory neurons are located in

Back 78

dorsal root ganglia

Front 79

order an action potential follows after sensory receptor is stimulated in a reflex arc

Back 79

1) sensory receptor
2)sensory neuron
3)interneuron
4)motor neuron
5)effector organ

Front 80

action potential originates in spinal cord and propagates to a peripheral. list correct order that impulses pass through strucures

Back 80

1)ventral root,
2)ventral ramus
3)plexus

Front 81

damage to the dorsal ramus of a spinal nerve results in

Back 81

-loss of sensation
-loss of motor function

Front 82

a collection of spinal nerves that join togehter after leaving the spinal cord

Back 82

plexus

Front 83

Which of these nerves arises from the cervical plexus?

Back 83

phrenic

Front 84

the skin on the posterior surface of the hand is supplied by the

Back 84

radial nerve

Front 85

the sciatic nerve is actually two nerves combined within the same sheath. the 2 nerves are

Back 85

-Common fibular(peroneal)
-tibial

Front 86

The muscles of the anterior compartment of the thigh are supplied by the

Back 86

femoral nerve