Spinal cord & spinal nerves

Question 1

What does the spinal cord do?

Answer 1

• conducts or transmits sensory impulses from the body to the brain
• conducts motor impulses from the brain to the body
• controls reflex action

Question 2

What is the epidural space?

Answer 2

fairly large space filled with adipose tissue that acts as a buffer around the spinal cord

Question 3

What are meninges?

Answer 3

membranes that surround the brain and spinal cord

Question 4

What protects the spinal cord?

Answer 4

spinal vertebrae, meninges, and epidural space

Question 5

What are the 3 types of meninges?

Answer 5

1. Dura mater- subdural SPACE filled with INTERSTITIAL fluid that anchors and protects
2. Archnoid mater- subarchnoid SPACE filled with CSF
3. Pia mater- thin MEMBRANE that follows the contour of the brain and spinal cord

Question 6

Whats the Dura Mater?

Answer 6

subdural SPACE filled with INTERSTITIAL fluid that anchors and protects

Question 7

What is the Archnoid mater?

Answer 7

subarchnoid SPACE filled with CSF

Question 8

What is the Pia mater?

Answer 8

thin MEMBRANE that follows the contour of the brain and spinal cord

Question 9

Pia mater is the most _______ of the meninges.

Answer 9

central or deep

Question 10

The arachnoid mater is ______ to the pia mater.

Answer 10

superficial

Question 11

THe dura mater is the most _______ meninges on the spinal cord.

Answer 11

superficial

Question 12

How long is the typical spinal cord?

Answer 12

42-45 cm long

Question 13

What is the foreman magnum?

Answer 13

the hole where the spinal cord attaches to the brain

Question 14

Which vertebrae does the spinal cord reach to as an infant and as an adult?

Answer 14

infant- L4

adult - L1

Question 15

When does the growth of the spinal cord stop?

Answer 15

age 5

Question 16

What makes the cervical enlargement and the lumber enlargement, enlarged?

Answer 16

there is an increase of nerve tissue

Question 17

Define conus medullaris

Answer 17

cone shaped end of spinal cord

Question 18

Define cauda equina

Answer 18

the dorsal ventral roots of lowest spinal nerves

Question 19

Define filum terminale

Answer 19

thread-like extension of the pia mater that stabalizes spinal cord in spinal canal

Question 20

What is a sulcus?

Answer 20

shallow groove

Question 21

Is the sulcus of the spinal cord on the ventral or dorsal side?

Answer 21

sulcus is on the dorsal side

Question 22

Is the Fissure of the spinal cord on the ventral of dorsal side?

Answer 22

fissure is on the ventral side

Question 23

What are the 2 spinal nerve roots that emerge from the spinal cord?

Answer 23

• dorsal root (sensory)

- ventral root (motor)

Question 24

What kind of fibres does the dorsal root have?

Answer 24

sensory fibres in the dorsal root

Question 25

What kind of fibres does the ventral root have?

Answer 25

motor fibres in the ventral root

Question 26

What is the dorsal root ganglion?

Answer 26

contains cell bodies of sensory neurons

Question 27

What neuroglial cells protect by wrapping themselves around the dorsal root ganglion?

Answer 27

satellite cells

Question 28

What is the motor tract?

Answer 28

- descending tract - has pyramidal (direct) and - has extrapyramidal tracts (indirect)

Question 29

What are sensory tracts

Answer 29

- ascending tracts - dorsal columns - spinothalamic - spinocerebellar

Question 30

What are the 3 sensory tracts?

Answer 30

- dorsal columns - spinothalamic - spinocerebellar

Question 31

What is the function of the dorsal (posterior) column (sensory tract)?

Answer 31

responsible for... - proprioception (know where your body parts are at any given time) - discriminative touch - two-point discrimination (deciphering whether there are 2 points or one when they are separating), - pressure - vibration

Question 32

What is the function of the spinothalamic (sensory tract)?

Answer 32

responsible for.. - pain - deep pressure - crude touch (rough, textured)

Question 33

What is the spinocerebellar tract (sensory tract) responsible for?

Answer 33

responsible for... | - unconscious proprioception (balance)

Question 34

What are the 2 types of motor tracts and their function?

Answer 34

- DIRECT pathways (pyramidal tracts); precise VOLUNTARY movement, happen right away - INDIRECT pathways (extrapyramidal tract); programmed or AUTOMATIC movement; coordinate gross movement and visual reflexes

Question 35

What is the function of direct pathways (pyramidal tracts)?

Answer 35

- precise - voluntary movement - happen right away

Question 36

What is the function of indirect pathways (aka extrapyramidal tracts)?

Answer 36

- automatic movements | - coordinate gross function and visual reflexes

Question 37

What are reflexes?

Answer 37

- fast, predictable, automatic responses to environment change

Question 38

What are integration centres?

Answer 38

- regions in the CNS that relay impulses from sensory to motor neurons directly (eg reflexes)

Question 39

Name the 4 important somatic spinal reflexes.

Answer 39

- stretch reflex - tendon reflex - flexor (withdrawal reflex) - cross extensor reflex

Question 40

What are the nerve membranes/coverings?

Answer 40

- epineurium - perineurium - endoneurium

Question 41

What is the stretch reflex?

Answer 41

aka patellar reflex - monosynaptic reflex (no interneuron) - prevents over stretching and injury

Question 42

What is activated when the tendon stretches in a tendon reflex?

Answer 42

Golgi tendon organ causes muscle to relax antagonistic muscle contracts

Question 43

What is the flexor cross extensor reflex?

Answer 43

a polysynaptic reflex involving several spinal segments - flexor reflex draws leg back - cross extensor reflex extends contralateral limb to maintain balance

Question 44

What is the physiological role of reflexes?

Answer 44

- protection- minimizes duration of exposure to noxious stimuli - maintains posture and balance

Question 45

What are plexuses?

Answer 45

complex networks of nerves

Question 46

What part of the spine does not form plexuses?

Answer 46

spinal nerve T2- T12 don't form plexuses

Question 47

What does the CERVICAL plexus innervate ?

Answer 47

C1-C5 innervates skin, muscle of head and neck, and superior shoulders and chest

Question 48

What does the BRACHIAL plexus innervate?

Answer 48

C5-T1 innervate shoulder and upper limb

Question 49

What does the LUMBAR plexus innervate?

Answer 49

L1-L4 innervates abdominal wall, external genitals and anterior medial thigh

Question 50

What does the SACRAL plexus innervate?

Answer 50

L4-S4 innervates buttock perineum and part of the lower limb

Question 51

What is dermatome?

Answer 51

areas of the skin supplied by one spinal nerve | - overlap of dermatomes prevents loss of sensation if one spinal nerve gets damaged