Lesson 6 - The Spinal Cord Flashcards
1
Q
the rostral portion of the neural tube undergoes significant growth and differentiation to form the ——-
A
brain
2
Q
The ——– ——– of the neural tube develops to form the spinal cord.
A
caudal end
3
Q
Cells on the dorsal side of the neural tube form the —- ——-, which subsequently becomes the dorsal horn (posterior).
A
alar plate
4
Q
Cells at the ventral end of the neural tube form the ——- ——, which then becomes the ventral horn (anterior)
A
basal plate
5
Q
At Fetal month 3, the cord ends at —— thus’ running the entire length of the vertebral canal. After that, the rate of elongation of the vertebral column exceeds that of the ——- ——–.
A
coccyx
spinal cord
6
Q
AT hat region does the spinal cord end, at birth?
A
L3
7
Q
At what section does the spinal cord end in human adults?
A
between ~L1-2, this position is fixed during childhood
8
Q
What is the function of the spinal cord and its associated spinal nerves?
A
They receive afferent fibres from sensory receptors of the trunk and limbs
They control movement of the trunk and limbs
They provide autonomic innervation for most of the viscera
9
Q
What are the boundaries of the spinal cord?
A
Foramen magnum to L1 or L2
Runs through vertebral canal of the vertebral column
10
Q
The spinal cord functions as a sensory and motor innervation of the body inferior to the head via spinal ———s
A
nerves
11
Q
The spinal cord acts as a 2 way conduction ——— between the brain and the body
A
pathway
12
Q
The ——– —— is a major centre for reflexes
A
spinal cord
13
Q
The adult spinal cord begins at the ——– bone and extends down to the space between the first and second ——— vertebrae
A
occipital
lumbar
14
Q
The adult ———- ——– does not extend the entire length of the vertebral column
A
spinal cord
15
Q
The adult spinal cord is around ?inch in men and ? inch in women
A
18
17
16
Q
How many different segments in the adult spinal cord?
A
30
At every segment, right and left pairs of spinal nerves (mixed; sensory and motor form)
17
Q
Name 3 major functions of the adult spinal cord
A
- Conduit for motor information, which travels down the spinal cord
- Conduit for sensory information in the reverse direction
- Coordination of certain reflexes
18
Q
Caudal to the lumber enlargement the spinal cord tapers abruptly to form a conical termination the ———– ———–.
A
conus medullaris
19
Q
From the tip of the conus medullaris, a strand of connective tissue called ——– ——–, extends caudally and is attached to the dorsal surface of the first coccygeal vertebra.
A
filum terminale
20
Q
Recall the 4 spinal cord segments and their associated spinal nerves
A
???
21
Q
Spinal cord segments are superior to where their corresponding spinal nerves emerge through i——— ———–.
A
intervertebral foramina
22
Q
What are the 3 meninges of the spinal cord?
A
Same as the brain
- Dura Mater
- Arachnoid Mater
- Pia Mater
23
Q
The —— mater is closely applied to the surface of the spinal cord and nerve roots.
A
pia
24
Q
Attached along a line midway between the dorsal and ventral roots of the spinal nerves is a flat continuation of the pia mater called the ———- ligament. The ligament intermittently projects out laterally forming shelves that tether the spinal cord to the arachnoid and the dura.
A
denticulate
25
How many enlargements does the spinal cord bear
2
Cervical enlargement and Lumbar enlargement
26
Why are the 2 enlargements of the spinal cord needed?
These are needed to accommodate the greater number of nerve cells and connections needed to process information related to the upper and lower limbs
27
Cervical enlargement:
- The spinal cord expansion that corresponds to the upper --------s
- Consists of spinal segments C4—T1;
- Provides innervation via -------- --------
limbs
brachial plexus
28
Lumbar enlargement:
- The spinal cord expansion that corresponds to the ----er limbs
- Consists of spinal segments L1—S3.
- Provides innervation via -------- --------
low
lumbosacral plexus
29
Spinal nerves:
- Part of the --------- system
- ? pairs attach through dorsal and ventral nerve roots
- Lie in ----------- foramina
peripheral
31
intervertebral
30
Spinal nerves:
- Divisions based on vertebral locations
- ? pairs attach through dorsal and ventral nerve roots
? cervical
? thoracic
? lumbar
? sacral
? coccygeal
- ----------- -----------: collection of nerve roots at inferior end of vertebral canal
31
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
Cauda equina
31
Spinal nerves exit from the ...?
vertebral canal
32
C1-C7 spinal nerves exit from the -------- ---------- above the 1st 7 cervical vertebrae
vertebral canal
33
C8 spinal nerve exits below the ?th cervical vertebra and the remainder leave below their corresponding vertebrae
7th
34
Because of the different lengths of the spinal cord and the vertical canal only in the cervical region do the spinal cord segments lie --------- to the corresponding vertebral bodies
adjacent
35
Below this level successive spinal nerve roots follow an increasingly oblique downwards course to reach the respective intervertebral foramina this is most marked for the lumber and sacral roots which descend below the termination of the chord in a leash like arrangement called the ------- ----------
cauda equina
36
Cervical spinal nerves exit from above the respective -----------
- Spinal nerve root 1 above C1
- Spinal nerve root 2 from between C1 and C2 etc.
vertebra
37
Each pair of spinal nerves connects the spinal cord with a specific ------ of the body.
region
38
Near the spinal cord each spinal nerve branches into two roots.
One branch, composed of --------- fibres, enters the spinal cord via the dorsal root; its cell bodies lie in a ------- ---------- that is outside the spinal cord.
The other branch, composed of ------- fibres, leaves the spinal cord via the --------- root; its cell bodies lie in specific areas of the spinal cord itself
sensory
spinal ganglion
motor
ventral
39
The ------------- nervous system is an anatomically defined division of the autonomic nervous system, being that part whose motor components run in cranial nerves III, VII, IX, and X and in the sacral nerves.
parasympathetic
40
The ----------- nervous system arises from the central nervous system, whose outflows are from the thoracic and upper lumbar spinal cord.
sympathetic
41
The functions subserved by the parasympathetic division are diverse. It exerts its effects on --------------ically controlled organs of the head, thorax, abdomen, and pelvis but not of the limbs or skin.
autonomically
42
--------- ------------------- neurons have their cell bodies in the central nervous system and make synapses in the ganglia close to or in the walls of the organs they supply
Parasympathetic preganglionic
43
Acetylcholine and nitric oxide are the major neurotransmitters of ------------- ----------- neurons.
parasympathetic postganglionic
44
The ------- mater is closely applied to the surface of the cord and nerve roots. Attached along a line midway between the dorsal and ventral roots of the spinal nerves is a flat continuation of the ----- mater called the ---------- ligament. The ligament intermittently projects out laterally forming shelves that tether the spinal cord to the arachnoid and the dura.
pia x2
denticulate
45
The ----------- mater lies between the pia and dura. A translucent membrane that invests the cord like a loose-fitting bag.
arachnoid
46
The sub arachnoid space lies between the pia and arachnoid and contains CSF which is produced in the --------- --------- system.
The outer covering of the cord the dura mater is a tough fibrous membrane and envelopes the cord loosely as does the arachnoid with which it is in contact (separated by a theoretical plane called the ------ ---------)
cerebral ventricular
subdural space
47
Dura separated from the bony wall of the vertebral canal by the -------space.
epidural
48
The spinal cord occupies the -------- -------- which provides support and protection.
vertebral canal
49
The approximate location of spinal cord segments relative to the bony vertebrae may be identified by reference to the ------ ------- ---------- of the vertebrae.
posterior spinous processes
50
Usually, the cervical cord segments lie ~? spine higher than their corresponding vertebrae
1
51
Thoracic cord segments lie ~? spines higher than their corresponding vertebrae
2
52
Lumbar cord segments lie ~?-? spines higher than their corresponding vertebrae
3-4
53
CSF role in the protection of the spinal cord?
1. Buffers CNS
2. Lightens brain
3. Removes toxic metabolites
4. Transports hormones
54
Lumbar Puncture:
The lowest part of the spinal canal does not contain the -------- --------consequently hollow needles can be safely inserted into the --------- ----------.
Can be used;
- to remove CSF for diagnostic purposes (lumbar puncture)
-to inject radio opaque substances for the radiological delineation of the spinal canal and its contents (----------)
Similarly, anesthetics may be introduced into the epidural space in surgical procedures i.e. epidural block
spinal cord
subarachnoid space
myelography
55
Lumbar Puncture:
Needle introduced into subarachnoid space to collect -- -- --
Collection of cerebrospinal fluid and its evaluation to determine infectious and inflammatory diseases affecting the CNS.
- Control CSF pressure
- Detect CSF pressure
- ----------- delivery
Lumbar spine needs to be flexed so needle can pass between spinal -----------s
Injection into correct space is vital and errors can be ---------
CSF
Anaesthetic
processes
lethal
56
The spinal cord is incompletely divided into two symmetrical halves by a posterior ----------- ---------- and an anterior -------- ----------.
median sulcus
median fissure
57
The -------- ----- ---------- is a shallow groove found in the midline of the posterior aspect of the spinal cord, medulla oblongata and pons. In the spinal cord, it is the external boundary of the posterior median septum and separates the two posterior ----------.
posterior median sulcus
funiculi
58
In the center of the chord is the small central canal which is continuous rostrally with the ----------- ------------ system
cerebral ventricle
59
Surrounding the central canal is the spinal gray matter consisting of nerve cell bodies their dendrites and -------- contacts.
synaptic
60
The outer part of the cord consists of ----------- matter which contains ascending and descending nerve fibres
white
61
Anatomy of the spinal cord:
- ----------- central canal
- -------- matter surrounds cavity
- --------- matter surrounds grey matter
- (white: ascending and descending tracts of axons)
- 'H' shaped on cross section
- --------- half of 'H': cell bodies of interneurons
- ------ half of 'H': cell bodies of motor neurons
Hollow
Gray
White
Dorsal
Ventral
62
Different spinal cord ---------s vary in the relative amounts and configuration of gray and white matter.
levels
63
Higher levels of the spinal cord contain greater amount of ----- matter because ascending tracts gain ---------s at each successive level whereas the opposite is true of descending tracts.
white
fibres
64
The ----- matter is H shaped with four protrusions the dorsal (or posterior) and ventral (or anterior) horns extending dorso- and ventro-laterally towards the attachment zones of the dorsal and ventral root fascicles respectively.
grey
65
Many -------- nerve fibers entering in the dorsal roots terminate in the dorsal horn while the ventral horn contains the cell bodies of motion neurons that exit through the --------- nerve roots and innervate skeletal muscle.
afferent
ventral
66
Both dorsal and ventral horns are particularly well developed at ----------- and ---------- levels in association with innervation of the upper and lower limbs
cervical and lumbar
67
Thoracic and upper lumbar sacral segments additionally possess a small lateral or intermediate lateral horn located between the dorsal and ventral horns which contains the cell bodies of ----------- ---------- neurons.
preganglionic sympathetic
68
The dorsal/posterior horn is the main site of termination of primary -------- (sensory) fibres. It includes the substantia ------------ which is important in transmission of nociceptive impulses to the brain (pain). E.g. iron burn to the hand as shown
afferent
gelatinosa
69
The lateral horn contains --------- -------- neurons.
preganglionic sympathetic
70
The ventral horn contains ---------- and --------- motor neurons also known as lower motor neurons – skeletal muscle innervation.
alpha and gamma
71
White Matter of the spinal cord:
----------- fibres: sensory information from sensory neurons/ receptors up to brain
------------ fibres: motor instructions from brain to spinal cord
- Stimulates contraction of body's --------s
- Stimulates secretion from body's -------s
------------ fibres: white matter fibres crossing from one side of cord to another
Most pathways cross (or decussate) at some point
Most synapse two or three times along the way e.g. in brainstem, or the thalamus
Ascending
Descending
muscles
glands
Commissural
72
White matter of the spinal cord:
Ascending pathways: sensory information by 3 orders of neurons from body up to more rostral regions of CNS
- ---------- -----------
- ------------ tracts
- ------------ tracts
Descending pathways: motor instructions via upper and lower order neurons from the brain to more caudal regions of the CNS
- ---------- (e.g. corticospinal)
- All others ("extrapyramidal")
Dorsal collumn
Spinothalamic
Spinocerebellar
Pyramidal
73
Damage to motor areas of the spinal cord = ----------------
Damage to the sensory areas of the spinal cord = -----------------
paralysis
paresthesias
74
Major ascending pathways for the somatic senses:
The ascending tracts (somatosensory pathways or systems) refer to the neural pathways by which sensory information from the peripheral nerves is transmitted to the ---------- ---------------
Functionally, the ascending tracts can be divided into the type of information they transmit – ------------------ or -------------------
cerebral cortex
conscious or unconscious
75
1. Conscious tracts (ascending tracts)
A: Dorsal column-medial ----------- pathway
discriminative touch pathway e.g. hugs tells you where you are touched and how hard they are squeezing. The sensation of how soft or hard they are squeezing is called touch pressure.)
B: ------------ pathway – conveys nociception (temperature) and non discriminative (crude) touch and pressure information.
lemniscal
Spinothalamic
76
2. Unconscious tracts (ascending tracts)
Spinocerebellar tracts which are important in proprioception which is perception of joint location, movement and muscle force.
77
Major Descending Pathways:
1. ----------- tracts
2. ---------------- tracts
Pyramidal
Extrapyramidal
78
The major descending motor pathway is composed of the pyramidal (-----------) system and the extrapyramidal (-----------) system
conscious
unconscious
79
1. Pyramidal tracts (pass through the pyramids of the medulla) are responsible for the conscious, voluntary control of the body and face muscles. They can be divided into two tracts.
-------------- tract:
Carries information from the cerebral cortex to the spinal cord and controls movement of the torso, upper and lower limbs.
Its projections have a strong influence on the activity of groups of spinal motorneurones, which innervate distal muscles of the hands and feet.
Most of the fibers (~85%) cross the midline in the decussation of the pyramids in the brain stem and then descend through the spinal cord in the lateral corticospinal tract, while the other 15% cross within the spinal cord at the level they terminate and are carried within the medial corticospinal tract.
---------- tract:
Composed of the upper motor neurons of the cranial nerves.
The muscles of the face, head and neck are controlled by the corticobulbar system, which terminates on motor neurons within brainstem motor nuclei.
Corticospinal
Corticobulbar
80
Extrapyramidal tracts (unconscious). These tracts do not pass through the pyramid of the medulla as they descend through the brain stem into the spinal cord, hence they are termed extrapyramidal pathways. Consist of the rubrospinal, tectospinal, vestibulospinal, reticulospinal and olivospinal tracts.
A: ----------- tract: Arises in the midbrain from the red nucleus, decussate almost immediately and terminate above the mid thoracic level of the spinal cord. Controls the tone of the flexor muscles.
B: ---------- tract: Arises in the colliculi, decussate almost immediately and terminate in the cervical and upper thoracic regions of the spinal cord. Control reflex, turning of the head and neck to auditory or visual stimuli.
C: ---------------- tract: arises from the lateral vestibular nucleus in the rostral part of the medulla and descends without decussating. Controls the muscles which maintain normal posture and balance.
D: ----------- tracts arise from the pontine and medullary reticular formation. They are partly crossed. Control automatic movements in locomotion.
E: ------------ tracts originating in the inferior olivary nucleus descends after decussating to cervical levels of the spinal cord. Coordinates movements of the head and neck and upper limbs contralateral to its origin.
Rubrospinal
Tectospinal
Vestibulospinal
Reticulospina
Olivospinal
