Chapter 14 - Spinal Cord and Spinal Nerves Flashcards
(73 cards)
0
Q
Size and location of the spinal cord
A
- Slender nerve column
- About 45 cm long
- Starts at foramen magnum and ends between L1 and L2 (does not go into the sacrum)
- 31 pair spinal nerves
1
Q
What system is the spinal cord part of?
A
cns
2
Q
Four major structures of the spinal cord
A
- Bilateral symmetry
- Gray and white matter
- Central canal
- 2 grooves
3
Q
Hole down the center of cord; continuous with brain ventricles; both contain CSF
A
Central canal
4
Q
2 grooves in the spinal cord
A
- Anterior median fissure
- Posterior median sulcus
5
Q
Swollen regions of the spinal cord
A
Enlargements
6
Q
Two enlargements in the spinal cord
A
- Cervical enlargement
2. Lumbar enlargement
7
Q
Inferior-most tip of spinal cord; cone shaped
A
Conus medullaris
8
Q
Means horse’s tail; bundle of nerves inferior to spinal cord
A
Cauda equina
9
Q
Inferior-most spinal nerve
A
Filum terminale
10
Q
Gray matter has projections called ____
A
Horns
11
Q
What does gray matter consist of?
A
Cell bodies, dendrites, and synapses
12
Q
Cell bodies are organized into nuclei in gray matter into what?
A
- Sensory
- motor
13
Q
Three interior horns in gray matter
A
Posterior horn
Anterior gray horn
Lateral gray horn
14
Q
Two gray commissures
A
Anterior commissure and posterior commissure
15
Q
What separates the commissures in gray matter?
A
The central canal
16
Q
The tracts and columns in white matter
A
- Posterior white column
- Anterior white column
- Lateral white column
- Ascending tract = sensory
- Descending tract = motor
17
Q
Three facts about meninges
A
- Membranes covering CNS
- Are similar in both brain and spinal cord
- Are split into layers called “mater”
18
Q
Means mother
A
Mater
19
Q
Three things superficial to Meninges
A
- Vertebrae consists of vertebral arches
- Epidural space
- Meninges connect to CT covering of spinal nerves
20
Q
- Space between meninges and vertebra
- Contains BV and adipose
A
Epidural Space
21
Q
- Tough mother
- Durable
A
Dura Mater
22
Q
Location of the dura mater
A
- Deep to epidural space
- Superficial to subdural space
23
Q
What is the dura mater stabilized by?
A
Coccygeal ligament
24
- Spidery mother
| - CT looks like a spider web
Arachnoid Mater
25
Location of the arachnoid mater
- Superficial to subarachnoid space
| - Contains CSF
26
- Delicate mother
| - Light layer adhering to chord
Pia Mater
27
What does the pia mater form?
Forms part of filum terminale
28
Spinal meninges (superfisical to deep)
- Vertebra
- Epidural space
- Dura mater
- Subdural space
- Arachnoid layer
- Subarachnoid space (with CSF)
- Pia mater
- Neural tissue
29
Components to the 31 pair of spinal nerves
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
30
- Usually sensory
| - Dorsal root ganglion that is composed of soma
Dorsal (posterior) root
31
- Nerve component
- No ganglion
- Usually motor
Ventral (anterior) root
32
Roots merge to form ___
Nerves
33
Because roots merge to form nerves, spinal nerves are usually what?
Mixes (both sensory and motor)
34
All roots go through _____
Intervertebral foramina
35
Three connective tissue coverings
1. Epineurium
2. Perineurium
3. Endoneurium
36
Surrounds the entire nerve
Epineurium
37
Surrounds bundles of 10-100 (known as fascicles)
Perineurium
38
Surrounds each individual axon of each neuron
Endoneurium
39
Offshoots of a nerve once it exits the vertebra
Rami
40
Three types of rami
Dorsal ramus
Ventral ramus
Ramus communicantse
41
A spitting in the ramus separating sensory and motor fibers
Rami communicantes
42
Two different kinds of communicantes
1. White ramus communicantes
| 2. Gray ramus communicantes
43
Sensory innervation by specific spinal nerves
Dermatomes
44
What will result in loss of sensation in dermatome?
Spinal cord damage
45
Detection method is apart of what?
Dermatomes
46
- Braid off ventral rami
Nerve plexuses
47
The regions where nerve plexuses are found
- Cervical
- Lumbar
- Sacral
- Most thoracic nerve are all isolated
48
Cervical plexus location and innervations
- C1-C4 and part of C5
- Innervate certain muscles of neck and torso
- Phrenic nerve
49
Where is the phrenic nerve?
C3, 4 and 5
| - Go to diaphragm
50
Where is the brachial plexus?
C4-C8 and T1
51
What does the brachial plexus innervate?
Chest, upper back, and arm
52
To ant. muscles of arms and skin of forearm
Musculocutaneous
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To muscles of forearm, hands, and skin of hands
Ulnar nerve
54
Same as ulnar
Median nerve
55
To post. muscles of arms and skin of forearms and hands
Radial nerve
56
- Last thoracic, lumbar, sacral, and coccygeal nerves
| - May be split into lumbar and sacral plexuses
Lumbosacral Plexus
57
What does the lumbosacral plexus innervate?
The lower limb regions
58
To adductors of leg
Obturator nerve
59
Motor impulses to leg and thigh and receive sensory from skin of legs and thigh
Femoral nerve
60
To muscles and skin in thighs, legs, and feet
Sciatic nerve
61
Explain reflexes
- Rapid automatic involuntary motor response to stimuli
- Help preserve homeostasis
- Occur at spinal cord or brain stem
- Do NOT require cerebral processing
- Cna be modified by cerebral control
62
How are reflexes classified?
- By development
- Site of processing
- Nature of motor response
- Complexity of neural circuit
63
Classifying reflexes by development with their definitions
```
Genetically = built in
Learned = acquired through repetition and/or experience
```
64
Classification of reflexes by site of processing
Spinal reflex = impulse only goes to the spinal cord
| Cranial reflex = makes it to the brain
65
Classification of reflexes by the nature of motor response
Somatic = influences the skeletal muscle system
| Visceral (autonomic) = influences the involuntary systems such as smooth muscle and glands
66
Classifying reflexes using the complexity of neural circuit
One synapse involved = monosynaptic
| More than one synapse = polysynaptic
67
Steps of a Reflex Arc
1. The receptor is stimulated by a detectible environmental stimulus
2. The receptor stimulates a SENSORY NEURON that sends a signal to the CNS for processing
3. The information is processed by being TRANSMITTED to the appropriate neurons (interneuron or motor neuron)
4. A MOTOR NEURON is stimulated, sending a signal to an EFFECTOR.
5. This results in behavior
68
A reflex stimulated by the stretching of a muscle
Stretch reflex
69
Receptors that detect stretching
Muscle spindle fibers
70
What is the effector in stretch reflex?
Contraction of the muscle
71
A patellar reflex is what kind of reflex?
Stretch reflex
72
What are the two functions of the patellar reflex?
1. Prevent muscles from being overstretched
| 2. Prevent one from falling forward
