1/10 Spinal Cord, Cell Biology, And Cranial Cavity Flashcards
(139 cards)
1
Q
What bones does the cap of the cranial cavity consist of?
A
Frontal, parietal, temporal, and occipital bones
2
Q
What does the cap of the cranial cavity enclose?
A
Superior aspect of cerebrum
3
Q
What bones do the walls of the cranial cavity consist of?
A
Frontal, parietal, temporal, occipital, and sphenoid bones
4
Q
What do the walls of the cranial cavity enclose?
A
anterior, posterior, and lateral aspects of cerebrum
5
Q
What bones do the walls of the basicranium consist of?
A
Frontal, ethmoid, sphenoid, temporal, and occipital bones
6
Q
What do the walls of the basicranium enclose?
A
inferior aspect of cerebrum, the cerebellum, and brainstem
7
Q
What is the basicranium divided into?
A
3 cranial fossae (anterior, middle, and posterior)
8
Q
What does the anterior cranial fossa contain?
A
Frontal lobes
9
Q
What does the middle cranial fossa contain?
A
Temporal lobes
10
Q
What does the posterior cranial fossa contain?
A
Cerebellum and brainstem
11
Q
What do the cranial fossa as a whole contain?
A
foramina for the passage of blood vessels and cranial nerves
12
Q
What runs through the olfactory foramina?
A
CN I
13
Q
A
A
Olfactory bulb
14
Q
What runs through the optic foramen (canal)?
A
CN II
15
Q
What runs through the superior orbital fissure?
A
CN III, IV, V1, VI
16
Q
What runs through the foramen rotundum?
A
CN V2
17
Q
What runs through the foramen ovale?
A
CN V3
18
Q
What runs through the foramen spinosum?
A
Middle meningeal artery
19
Q
What runs through the carotid canal?
A
Internal carotid artery
20
Q
B
A
Optic nerve
21
Q
C
A
Ophthalmic nerve
22
Q
D
A
Maxillary nerve
23
Q
E
A
Mandibular nerve
24
Q
J
A
Internal carotid artery
25
K
Oculomotor nerve and trochlear nerve
26
L
Abducent nerve
27
M
Middle meningeal artery
28
What runs through the internal acoustic meatus?
CN VII, VIII
29
What runs through the jugular foramen?
Jugular vein (internal)
CN IX, X, XI
30
What runs through the hypoglossal foramen (canal)?
CN XII
31
What runs through the foramen magnum?
Vertebral arteries
CN XI
Spinal cord
32
What is contained in the meninges and spaces between the skull/vertebrae and brain/spinal cord?
Dura, arachnoid, and pia mater
Epidural space
Subdural space
Subarachnoid space
33
What does the epidural space contain?
Adipose in vertebral canal
34
What does the subdural space contain?
Potential space
35
What does the subarachnoid space contain?
Cerebral spinal fluid (CSF)
36
What are the two fibrous layers that the cranial dura mater is made of?
Periosteal layer
Meningeal layer
37
What is the periosteal layer of dura mater adherent with and continuous with?
adherent to the cranium; continuous with external periosteum of skull
Does not continue to vertebral canal
38
What is the meningeal layer continuous with and fused to?
continuous into the vertebral canal (only part of dura to do this)
Fused to periosteal layer
39
What are the exceptions of the fusing of the periosteal layer and meningeal layer? Examples?
Dural infoldings
-falx cerebri, tentorium cerebelli
Dural venous sinuses
40
What is the spinal cord?
Major reflex center and conduction pathway between body and brain
Continuation of the caudal medulla at the foramen magnum
41
Where does the spinal cord course, what is the protection?
through the vertebral canal
protected by vertebrae, epidural fat, spinal meninges, and CSF
42
Where does the spinal cord taper, what spinal level?
Tapers caudally as the conus medullaris at the L1/L2 vertebral level
43
Caudal to conus medullaris, the remaining spinal nerve roots occupy…
lumbar cistern as the cauda equina
44
What arises from the tip of the conus medullaris?
Filum terminale internum
45
What is the filum terminale internum composed of?
Vestigial neural and connective tissue, covered in pia mater
46
What does the filum terminale internum perforate and attach to?
distal end of the dural sac, gains arachnoid and dural layers
continues as the filum terminale externum (coccygeal ligament) to attach to the dorsum of the coccyx
47
What are the two regions in which the spinal cord is enlarged to accommodate increased neural connections of the limbs?
Cervical enlargement
Lumbar (lumbosacral) enlargement
48
What spinal segments does the cervical enlargement contain?
C4-T1
49
What do the anterior rami of the cervical enlargement form?
The brachial plexus to the upper limb
50
What spinal segments does the lumbar (lumbosacral) enlargement contain?
T11-S1
51
What do the anterior rami of the lumbar (lumbosacral) enlargement form?
Lumbar and sacral plexuses to the lower limb
52
What is the blood supply to the spinal cord (where do they come from)?
1 anterior spinal artery (from vertebral)
2 posterior spinal arteries (from vertebral/PICA)
53
What do the supplemental blood supplies from spinal branches become?
Segmental medullary arteries
Radicular arteries
54
What do the segmental medullary arteries supply? Do they reach longitudinal arteries? Anastemos?
Mostly at cervical and lumbar enlargements
Reach the longitudinal arteries, they do anastemos
55
What do the radicular arteries supply? Do they reach longitudinal arteries? Anastemos?
Supply posterior and anterior nerve roots
Do not reach longitudinal arteries, do not anastemos
56
G
Facial nerve and vestibulococlear nerve
57
H
Glossopharyngeal nerve, vagus nerve, and accessory nerve
58
R
Hypoglossal nerve
59
Does the vertebral column or spinal cord grow quicker? What is the consequence?
Vertebral column grows faster than the spinal cord, pulling spinal (segmental) nerves inferiorly as they exit the vertebral column
60
Do segmental levels of the spinal cord align with vertebrae levels?
No
61
Where do cervical spinal nerves exit? How does this change?
Cervical spinal nerves exit above vertebrae of the same level
C8 spinal nerve exits below the 7th cervical vertebra, then all other spinal nerves exit below the vertebrae of the same level.
62
What is gray matter?
Unmyelinated cell bodies of lower motor neurons, interneurons, sensory projection neurons
63
What is white matter?
myelinated axons (ascending and descending tracts)
64
What provides sensory information to the CNS?
Dorsal (posterior) roots
65
What provides motor information to the CNS?
Ventral (anterior) roots
66
What information do spinal nerves contain?
both sensory and motor information
67
A
Posterior gray commissure
68
B
Dura mater
69
C
Arachnoid mater
70
D
Central canal
71
E
Anterior gray commissure
72
F
Pia mater
73
G
Anterior median fissure
74
H
Ventral root
75
I (i)
Dorsal root ganglion
76
J
Anterior gray horn
77
K
Dorsal root
78
L
Lateral gray horn
79
M
Posterior gray horn
80
N
Posterior median sulcus
81
What is the internal anatomy of the cervical portion of the spinal cord?
Thickest white matter
-Most ascending fibers present, Descending fibers have not exited
Large ventral horns
-LMN for UL
82
What is the internal anatomy of the thoracic portion of the spinal cord?
Relatively little gray matter; primarily tracts
Contains lateral horn for IMLCC
83
What is the internal anatomy of the lumbar portion of the spinal cord?
Large ventral horns
-LMN for LL
84
What is the internal anatomy of the sacral portion of the spinal cord?
Mostly gray matter
• Most descending fibers exited
• Few ascending fibers have joined
85
What are the deep tendon reflexes?
Hyporeflexia, hyperreflexia
86
What is the cause of hyporeflexia?
* lower motor neurons
damaged muscles, sensory neurons, neuromuscular junction; acute upper motor neuron lesions
87
What is the cause of hyperreflexia?
upper motor neuron lesions
88
What are dendrites?
Highly branched processes that typically function as the “receiving end” for information coming to the neuronal cell body
89
What is the axon hillock?
point of axon origin from the cell body; where action potentials begin
90
What is the axon?
A single process arising from the neuronal cell body that carries information away from the cell body toward other cells
91
What is the axon terminal?
where the neuron communicates with other cells
92
What is the synaptic cleft?
intercellular space between pre-synaptic and post-synaptic neurons
93
What is contained in the neuronal cell body (soma) in the cytoplasm?
contains the nucleus and organelles that provide energy and synthesize chemical signaling molecules (neurotransmitters) that are critical in cell-to-cell communication
94
What are the different types of neurons?
Unipolar
Bipolar (one type is Pseudounipolar)
Multipolar
95
What does a unipolar neuron look like? What does it control?
No dendrites; cell body receives incoming signals. Single axon with multiple processes at the terminal. Uncommon in humans; exocrine gland secretion and smooth muscle contractions.
96
What do bipolar neurons look like? What do they control?
Two processes that arise from opposite poles of cell body. Flow of information is from one process to the other.
Subtype is the pseudounipolar neuron
Many sensory neurons are bipolar/pseudounipolar.
97
What does a multipolar neuron look like? What does it control?
Complex array of dendrites, single axon that branches extensively. Most brain/spinal cord neurons and motor neurons are multipolar.
• Long axons–projection neurons
• Short axons–interneurons
98
What is a synapse?
the specialized site of the axon where the neuron communicates with another cell
99
What is the synaptic cleft?
narrow gap between pre- and post-synaptic cells into which neurotransmitters are released
100
What are synaptic vesicles?
filled with chemical neurotransmitters that are released upon stimulation
101
What are neuroglia?
Second major cellular constituent of nervous system. Provide structural and metabolic support for neurons during development and in maturity
102
What are the different kinds of neuroglia?
Ependymal cells
Microglia
Astrocytes
Oligodendrocytes
Schwann cells
103
What do ependymal cells look like, where are they?
Single layer of ciliated cuboidal cells lines all ventricles of the brain and the central canal of the spinal cord.
104
What is the function of ependymal cells?
Help to circulate CSF through the ventricular system.
Apical surface also contains microvilli which contribute to CSF absorption.
Modified ependymal cells form the choroid plexus, which secretes CSF.
105
What are microglia, where do they come from?
Phagocytotic scavenger cells derived from bone marrow
106
What do microglia look like?
Small cells with elongated nuclei and spikey processes
107
What is the function of microglia?
Normally 5% of all neuroglia but can rapidly proliferate and activate in regions of injury and disease
Destroy invaders, remove debris, and promote tissue repair
108
What do astrocytes look like? What is their basic function?
Abundant star-shaped glia critical for neuronal nourishment and synapse development and function
109
What do astrocytes have?
Thin processes that envelope blood vessels and ensheath neurons and synapses (perivascular and perineural feet)
110
What do astrocytes do (in depth)?
Regulate extracellular ion and neurotransmitter concentrations:
• Potassium (K+) buffers
• Clearance of glutamate from synaptic cleft and degradation of other neurotransmitters
• CA2+ signaling waves to nearby astrocytes
111
What is the function of oligodendrocytes?
Myelinating cell of the CNS
produces myelin sheaths for small segments of up to 30 axons.
They contribute to the structural framework of the CNS by stabilizing axonal positions.
112
What is myelin?
insulating material that allows rapid conduction of electrical signals along the axon
113
What is the function of Schwann cells?
Myelinating cell of the PNS
Myelin wraps concentrically around segments of the axon. Number of layers is proportional to the diameter of the axon.
Contain nodes of Ranvier
114
What are nodes of ranvier?
Regularly placed segments of myelin sheath separated by unmyelinated gaps of approximately 1μM
Increase the speed of conduction
Nodes have a higher density of Na+ channels and are easily excitable
115
How do nodes of ranvier increase the speed of conduction?
the signal jumps from one node to the next, a process called saltatory conduction
116
What are the parts of the basicranium that divide the anterior/middle and middle/posterior foassae?
Anterior/middle: sphenoidal crest
Middle/posterior: superior border of petrous part of temporal bone
117
When is the spinal cord the same length as the vertebral column?
12 weeks gestation
118
In which ways are neurons excitable?
Electrically and chemically
119
A
Optic (CN II)
120
B
Oculomotor (CN III)
121
C
Trochlear (CN IV)
122
D
Trigeminal (CN V)
123
E
Abducens (CN VI)
124
F
Facial (CN VII)
125
G
Vestibulocochlear (CN VIII)
126
H
Glossopharyngeal (CN IX)
127
I (i)
Vagus (CN X)
128
J
Spinal accessory (CN XI)
129
K
Hypoglossal (CN XII)
130
Where does the optic nerve arise from in the brainstem?
Posterior/dorsal diencephalon
131
Where does the oculomotor nerve arise from in the brainstem?
Posterior/dorsal midbrain
132
Where does the trochlear nerve arise from in the brainstem?
Lateral midbrain
133
Where does the trigeminal nerve arise from in the brainstem?
Lateral-dorsal/posterior pons
134
Where does the abducens nerve arise from in the brainstem?
Posterior/dorsal-caudal pons
135
Where does the facial and vestibulocochlear nerve arise from in the brainstem?
Lateral-posterior/dorsal-caudal pons
136
Where does the glossopharyngeal nerve arise from in the brainstem?
Lateral to olive in rostral/anterior medulla
137
Where does the vagus nerve arise from in the brainstem?
Lateral to olive in middle medulla
138
Where does the spinal accessory nerve arise from in the brainstem?
Lateral to olive in dorsal medulla to spinal cord
139
Where does the hypoglossal nerve arise from in the brainstem?
Between olive and pyramid in middle medulla
