4 - Zill - Nervous System

Question 1

Legal Definition of Death

Answer 1

Irreversible cessation of function of nervous system

Question 2

You just stepped on a nail, how does the signal get to your nervous system?

Answer 2

Afferent Axon conducts toward CNS on sensory neuron

Motor Neuron conducts on Efferent Axon away from CNS to lift leg

Question 3

What can be used to test nervous system function and locate site of lesion?

Answer 3

Reflex tests

Question 4

How many spinal nerves are there?

Answer 4

31

Question 5

Cervical Spinal Nerves exit point?

C1-C7

C8 and all others

Answer 5

C1-C7:

Above corresponding vertebrae

C8-all:

Below corresponding vertebrae

Question 6

Somatic Nervous System

Efferents v Afferents

Answer 6

Voluntary, conscious movement

Efferents: Control skeletal muscles, volunary activities, conscious actions

Afferents: Sense of body position, sensation of touch, pain, pressure

SAME:

Sensory

Afferents

Motor

Efferents

Question 7

Autonomic Nervous System

Answer 7

Involuntary, unconscious part of nervous system

Question 8

Visceral Efferents

Answer 8

Parasympathetic and sympathetic, control smooth and cardiac muscle, glands, and internal organs.

Largely unconscious–automatic

Question 9

Where are the Autonomic, Sympathetic Chain of Ganglia located?

Answer 9

para (side) vertebral

Question 10

Where do the dorsal and ventral roots combine?

Answer 10

Spinal nerve

Question 11

Where are cell bodies of all sensory neurons located?

Answer 11

Doral Root Ganglion

Question 12

Dermatome

Answer 12

Area of skin innervated by a single spinal nerve

Question 13

What are dermatomes used for clinically?

Answer 13

Testing nerve damage, anesthesia

Question 14

What are the dermatomes of the hand?

Answer 14

Thumb = C6

Pointer, Middle = C7

Ring, Littler = C8

Question 15

What level of a herniated disc would produce numbness of the thumb?

Answer 15

Thumb = C6,

So herniation ABOVE: C5 and C6

Question 16

What level of herniated disc would produce numbness in the little finger?

Answer 16

Little finger = C8

Rule: C1-C7 = Above, C8 = Below

Herniation between C7 - T1

Question 17

Spinal Nerves, how many of each?

Answer 17

Cervical - 8

Thoracic - 12

Lumbar - 5

Sacral - 5

Coccygeal - 1

Question 18

What is the rule for exiting of spinal nerves?

Answer 18

C1-C7 = Above

At C8 and below = Below

Question 19

Dermatomes of the lower extremity:

Inguinal Ligament (anterior to hip)

Big Toe

Little Toe

Answer 19

Inguinal Ligament - L1

Big Toe - L4

Little Toe - S1

Question 20

Dorsal Ramus

Ventral Ramus

Answer 20

Dorsal Ramus - Sensory and motor axons to region of back

Ventral Ramus - Sensory and motor acons to other parts of body

Question 21

Plexus

Lumbosacral Plexus

Answer 21

Forms from ventral rami of spinal nerves

Lumbosacral - innervates lower extremity

Question 22

Conus Medullaris

Location in Newborn?

Location in Adult?

Answer 22

Where spinal cord ends

Newborn: L3

Adult: L1

Question 23

Cauda Equina

Answer 23

Dorsal and ventral roots that grow down from the conus medullaris

Question 24

Dura Mater

Where does the dural sac end?

Answer 24

Tough outer layer around spinal cord, below L1 adult (L3 newborn), dural sac surround cauda equina.

Dural sac ends inferiorly at S2

Question 25

Epidural Space What does this space contain?

Answer 25

Separation of dural sac from inner side of vertebral canal Also contains **Internal Vertebral Venous Plexus** **Only VEINS and FAT**

Question 26

Epidural Anesthesia

Answer 26

Can block conduction in spinal nerves by injection into epidural space; effect is by diffusion.

Question 27

Arachnoid Layer Subarachnoid Layer

Answer 27

Attached to inner side of dura, has fine strands that extend to the pia mater Subarachnoid layer contains **CSF**

Question 28

Pia Mater

Answer 28

Thin layer, contains blood vessels supplying cord.

Question 29

Denticulate Ligaments Use?

Answer 29

Projections of pia on each side of cord that extend to arachnoid to inner dura; 21 pairs stabilize spinal cord. ## Footnote **Used as landmarks in neurosurgery**

Question 30

Filum Terminale

Answer 30

Thin strand of Pia that extends below Conus Medullaris, pierces S2, attaches to **Co1**

Question 31

Where is CSF produced?

Answer 31

Choroid plexuses, mostly in brain

Question 32

Spinal Tap location?

Answer 32

Must be **below** Conus Medullaris (inferior to) **Adult: Between L3-L4, or L4-L5** **\*\*\*Children: L4-L5\*\*\*** (spinal cord extends to L3)

Question 33

Where does the dural sac end? Where does the filum terminale end and attaches? Where does the spinal cord end in children/adults?

Answer 33

Dural Sac - S2 Filum Terminal End/Attach - Co1 Spinal Cord End: Adult - L1 Child - L3

Question 34

What yields the first and second pop during a spinal tap?

Answer 34

Ligamentum Flavum (sudden yield, first pop) Dura mater (sudden yield, second pop)