Lecture 14 content

Question 1

Neural tube

• forms?
• what becomes what?
• filled?
• Nerves?

Answer 1

• Ectoderm folds inward to for holow tube
• anterior end swells - becomes hollow - hollow brain
• posterior portion - Hollow - spine and central canal
• filled with CSF
• segmented from brain (12) and spinal cord (31)

Question 2

What is the typical cross section of the spinal cord?

Answer 2

Cortex: white matter = myelinated axons (more superficial)
Medulla: Grey matter = cell bodies , unmyelinated axons
central canal filled with CSF

Question 3

Name the 3 meningeal layers superficial to deep

Answer 3

Dura mater
- sub dural space
Arachnoid 
- sub arachnoid space
Pia mater

Question 4

Describe the Dura mater?

Answer 4

thick, fibrous, outermost

• target for epidural block
• endosteum of the brain case
• epidural space btw dura mater and vertebral canal
• subdural space between dura and arachnoid

Question 5

Describe the arachnoid Layer

Answer 5

thin intermediate layer (spider web like)

• subarachnoid space between arachnoid and Pia mater
• blood vessels supported by arachnoid trabeculae
• sub arachnoid space filled with CSF
• target for spinal tap

Question 6

Describe the Pia mater layer

Answer 6

vascular, innermost layer, adheres to gyri

• Pia mater is firmly attached to the spinal cord
• blood vessels from network on surface of cord

Question 7

What is meningitis?

Answer 7

inflammation of meninges: bacteria, virus, inury

- any meningeal layer

Question 8

what is the general structure of the spinal cord?

Answer 8

18 inches long

• conus medullaris
• filum terminale
• posterior median sulcus
• anterior fissure

Question 9

conus medullaris

Answer 9

tapered conical termination of cord

Question 10

filum terminale

Answer 10

• fibers extending from conus > coccyx

Question 11

Posterior median sulcus

Answer 11

shallow longitudinal groove

Question 12

anterior median fissure

Answer 12

deep longitudinal groove

Question 13

where do spinal nerves leave/enter spinal column?

Answer 13

intervertebral foramen

Question 14

What does the dorsal root contain?

Answer 14

sensory nerves and their bodies

Question 15

What does the ventral root contain?

Answer 15

motor neurons

Question 16

What does the dorsal Ramus innervate?

Answer 16

skin/muscles of back

Question 17

What does the ventral ramus innervate?

Answer 17

• skin/muscles of thorax, abdomen, limbs

Question 18

rami communicantes is part of what system?

Answer 18

ANS

- Rami: contain sensory and motor

Question 19

What nerve is superior to C7, T1, T2

Answer 19

- named on what is above it!
C7 = Nerve C7
-------------------------This is where it switches
T1 = C8 
T2 = T1

Question 20

How many spinal nerves are their? what are the segments?

Answer 20

31 pairs of spinal nerve
8 cervical
12 thoracic 
5 lumbar 
5 sacral
1 coccygeal

Question 21

What is referred pain? (convergent - projecton)

Answer 21

convergent - projecton) = perception does not equal source of pain
when the pain that you are feeling are not in the place where the problem is (heart attack = left arm)

Question 22

What is Dermatomes?

Answer 22

segmented innervation of skin

Question 23

What are the 3 nerve plexus?

what do they provide?

Answer 23

• cervical plexus (C1 - C5)
• Brachial plexus (C5 - T 1)
• Lumbosacral plexus (T12 - S4)

Nereves that provide motor input to a muscle
provide sensory feed - back from m.s. and skin

Question 24

Name the branch of the Cervical plexus and what they innervate?

Answer 24

(C1 - C5)
- phrenic nerve (C3) - controls contraction of the diaphragm
Neck muscles , levator scapulae, part of trapezius and SCM

Question 25

Name the branch of the Brachial Plexus and what they innervate? (ARMUM)

Answer 25

(C5 - T1)
axillary n. - deltoid and teres minor
radial n. - all extensors (arm, forearm, wrist, fingers)
Median n. - flexors of wrist and fingers
ulnar n. - flexor carpi ulnaris
Musculocutaneus n. - flexors of the arm and forearm

Question 26

What is a upper plexus injury?

Answer 26

Erbs palsy

Question 27

What is a lower plexus injury?

Answer 27

Klumpk’es palsy

Question 28

Name the branches of the lumbosacral plexus? and what do they innervate?

Answer 28

• (T12-S4)
  gluteal n - gluteal muscles
  obturator n. adductors of thigh
  femoral n. - extensrs of the knee (vastus m. rectus femoris m.)
  tibial n - semi’s, biceps femoris (long head) flexors of ankle
  Fibular n. - biceps femoris (short head) fibularis muscles
  Fibular n. - dorsi-flexors of ankle/toes
  Pudendal n. Gi/Ug sphinters, external genitalia (S2-S4)

Question 29

what are reflexes characterized by?

Answer 29

Development history: innate or acquired
processing site: brain or spinal cord
circuit complexity: monosynaptic or polysynaptic
motor response: somatic or viceral (ANS)

Question 30

What is the 5 step process?

Answer 30

1. stimulis of the receptors pain or stretch
2. sensory neuron (dorsal root) sends info to the CNS
3. Relays info
   - sensation relayed to brain
   - sensation replayed to pool of motor neurons
4. Motor neuron (ventral root) is activated
5. Peripheral effectors respond muscles and glands

Question 31

What is a cerebrovascular accident?

Answer 31

(CVA stroke)

Question 32

What is paralysis?

Answer 32

loss of motor control

Question 33

What is parapelegia?

Answer 33

Paralysis of the lower limbs (L1)

Question 34

What is Hemalegia?

Answer 34

paralysis of one side of the body

Question 35

What is quariplegia?

Answer 35

paralysis of all 4 limbs C6 C4

Question 36

What is Spina Bifida?

Answer 36

malformation of spine and spinal cord