term 2 Flashcards
-CSF blood -cranial nerve 1/2 -spinal cord 1/2/3 (105 cards)
1
Q
what is the ventricular system?
A
remnant of the space (lumen) of the neural tube, and interconnected series of cavities (ventricles throught the CNS)
2
Q
how many ventricles are there?
A
4, ,two lateral the 3rd and 4th.
3
Q
what are the ventricles lined with?
A
ependymal cels> vascularized pia> secretory cells (choroid plexus)
4
Q
what produces CSF?
A
choroid plexus,
5
Q
whats the function of the ventricular system? (purpose)
A
brain protection, nutrient and waste transport, and transport of neuroendocrine factors (hormones)
6
Q
where sit the choroid plexus located?
A
there are 2 locations (lateral/3rd ventricle, and the 4th ventricle)
7
Q
what does the choroid plexus formation contain?
A
ependymal cells, fenestrated capillaries, pia and choroid epithelium.
8
Q
how is the cerebrospinal fluid made?
A
- filtration of blood plasma through fenestrated capillaries, 2. activate transport of ion across the choroid epithelium, 3. osmotic balance is maintained by flow of water across specific water channels.
9
Q
go into detail about the ependymal cells?
A
they are ciliated cells that line the ventricles of the brain and central canal of the spinal cord. responsible for CSF circulation.
10
Q
what is hydrocephalus?
A
“water on the brain”
11
Q
what are the 3 components of the blood brain barrier?
A
choiroid epithelium ( regulates wat gets into the CSF from the plasma) intracerebral capillary ( barrier to rest of body- tight junctions) arachnoid barrier (prevents diffusion from outside CNS into subarachnoid space)
12
Q
how is the arterial blood transported to the brain?
A
through 2 main branches from the dorsal aorta:
1) internal carotid arteries- supply the brain
2) vertebral arteres- along with basilar artery supply the brain, brainstem and cerebellum
13
Q
what is the purpose of the circle of willis?
A
is a circulatory anastomosis that supplies blood to the brain and surrounding structures. it also connects the anterior and posterior circulatory system.
14
Q
what determines/controls the cerebral blood flow?
A
- viscosity of blood
- how dilated blood vessels
- cerebral perfusion pressure
15
Q
how do you detect aneurysms?
A
using an angiogram, and you use an indicator in the blood supply to get an x-ray vision of arteries in the brain. If certain arteries looks as if they are going to burst/have burst that is evidence of aneurysms (blood build ups)
16
Q
how is blood drained form the brain?
A
via two sets of veins
- superficial veins
- deep veins
17
Q
what are superficial veins?
A
they lie on the surface of each cerebral hemispheres within the subarachnoid space. they drain cerebral cortex, and underlying white matter
18
Q
what are the deep veins?
A
they are drain structures in the walls of the ventricles, and the converge on the internal cerebral veins.
19
Q
what is the importance of venous drainage?
A
importace in relation to neruosurgical procedures
important to neurologist- in clinical sunthroms.
A VENOUS OBSTRUCTION-? THROMBOSIS
20
Q
how many pairs of cranial nerves are there?
A
12, and they are numbered sequentially in the rostral to caudal order in which they arise form the brain.
21
Q
what do the cranial nerves do on a general term.
A
carry sensory information from ipsilateral receptors
22
Q
what are the exceptions of the cranial nerves?
A
trochlear nerves- all fibres originate form motor neuron cells in the contralateral 1/2 of the CNS
oculomotor- some fibres originate form contralateral motor neuron cell bodies
23
Q
how are the cranial nerves attached?
A
attached dorsally or dorsolatterally except for the trochlear nerves- attach ventrally.
24
Q
the cranial nerve function can be sensory, how?
A
olfactory bulb-smell
optic nerve- sight
vestibulocohlear nerve- hearing and equilibrium.
25
the cranial nerve function can be motor, how?
occulomotor nerve- movement, pupil, lens
abducens nerve- eye movement
accessory nerve- head and shoulder movements
hyoglossal nerve- tongue movements.
26
the cranial nerve function can be both motor, and sensory, how?
trigeminal nerve- facial sensation, chewing
facial nerve- expression and taste
glossopharyngeal never- swallowing, taste
vagus nerve- visceral sensory, taste, swallowing, speaking, preganglionic parasympathetic
27
what is the hypoglossal nerve- 12
its a motor nerve with lower motor neurons, its somatic effect fibres for muscles of the tongue, and it arises from hypoglossal nucleus.
28
what is the pathway for the hypoglossal nerve?
the upper motor neuron cell body is within the pre-central gyrus, the axons are called corticobulbar fibers.
basically the axons enter internal capsule with the corticospinal tract, through the cerebral peduncle then the pons, and it crosses the midline within the rostral medulla. finally it terminates in the hypoglosal nucleus.
29
what is the spinal accessory Nerve- 11
its a motor nerve, it arises form column of lower motor neurons i the anterior gray horn, its a somatic efferent fibres for trapezius and sternocleidomastoid.
30
what are the nucleus ambiguus?
its the lower 'lines' that merge commissural nucleus. they are special visceral efferent fibers, and the supply muscles of larynx and pharynx
31
what is the solitary nucleus?
it extends from the lower pons to gracile nucleus, and its full of afferent fibers.
32
what is the regions of the solitary nucleus?
gustatory, dorsal respiratory, baroreceptor, and visceral afferent.
33
what is the function of the gustatory nucleus?
primary afferent supplying taste buds
34
what is the function of the dorsal respiratory nucleus?
afferent that controls inspiration-> movement and timing
35
what is the function of the baroreceptor nucleus?
receives primary afferent supplying baroreceptors in carotid sinus and aortic arch
36
what is the function of the visceral afferent nucleus?
includes commissural nucleus; within brainstem; recieves primary afferent supplying alimentary and respiratory tracts.
37
the glossopharyngeal nerve-9
what are the motor components?
what are the parasympathetic components?
what are the sensory components?
motor- nucleus ambiguus- larynx/pharynx
para- inferiror salivatory nucleus- parotoid gland
sensory- informaiton terminates in solitaty nucleus and spinal trigeminal nucleus
38
what is the Vagus nerve- 10
its the "wandering nerve"
its the largest cranial nerve
12 branches
and is a mixed nerve
39
what are the sensory components of the vagus nerve 10?
terminates in the solitary nucleus
terminates in the sylvian parietal-temporal region
terminates in the spinal trigeminal nucleus
general sensation in the pharynx, larynx, esophagus, tympanic membrane, and external ear
40
what are the motor components of the vagus nerve 10?
originates in the nucleus ambiguus muscles of the larynx, pharyns
41
what are the parasympathetic components of the vagus nerve 10?
rest and digest
dorsal motor nucleus= collection of preganglionic parasympathetic neurons in the brainstem
widely distributed throughout the cardiovascular, respiratory, GI systems
innervates most abdominal organs
42
what is GSA?
general somatic afferent= sensory-> pain and temperature
43
what is GSE?
general somatic efferent= motor ->musclews for chewing/movement
44
what is SSA?
special somatic afferent
| function: vision, hearing, balance
45
what is SVA?
special visceral afferent
| function: taste, smell
46
what is GVE?
general visceral efferent
| function: nerves that carry motor fibres from the autonomic nervous system that innervate visceral smooth muscle
47
what is SVE?
special visceral efferent
| function: swallowing and respiration, where innervate muscles of larynx and pharynx,
48
what is the function of the vestibulocochlear nerve-8
there are two branches
1. chochlear (auditory) never ->sensory function in hearing
2. vestibular nerve-> balance and equilibrium
49
what is the anatomy of the vestibulocochlear nerve?
the vestibular portion is the vestibular never +4 vestibular nuclei in the brainstem (mendulla)
50
What is the medial longitudinal fasciculus (MLF)
its a pai of white matter bibre tracts that pass through the brainstem, it integrates informaiton from the 3, 4, 6, and 7.
its purpose is coordination and synchronization of eye movements.
51
what is the trigeminal nerve- 5 and how is it a mixed nerve?
its primarily sensory through touch, pain and temperature and its motor function is masticating (biting, chewing, swallowing).
52
in the trigeminal nerve, what does the sensory affarents arrive through?
3 divisions:
1. opthalmic branch- V1
2. maxillary branch- V2
3. mandibular branch- V3
53
what is the sensory pathway of the trigeminal ganglion?
within mid-pons, cell bodies of afferent fibres live here. it gives rise to secondary nerve root.
54
what is the sensory pathway of the main sensory nucleus?
these second-order neurons cross the midline, join medial lemniscus
55
what is the sensory pathway of the thalamus- VPM?
these neurons projects to somatosensory cortex within postcentral gyrus.
56
describe the facial nerve 7.
its a mixed nerve that innervates muscles involved in facial expressions and taste. the ell bodies within facial motor nucleus of the caudal pons. it emerges form the brainstem between the pons and medulla. it innervate ipsilateral half the face.
57
what does the oculomotor nerve 3 control?
eye movement, pupil constriction, maintains open eyelid and innervation to 4 extra-ocular muscles
58
what nerve is responsible for sense of smell?
olfactory nerve 1
59
what does the optic nerve and tract-2 do?
transmits visual information from the retina to the brain.
60
what is the purpose of the retina?
it convert patterns of light into action potentials in the optic nerve. it takes 5 cell types to do this
61
the informaiton from the optic nerve is involved in what?
1. regulating circadian rhythms
2. reflex control of the pupil and lens
3. movement of the head and eyes.
62
the spinal cord is segmented, what is a segment and how many are there?
```
A SEGMENT IS A PORTION OF THE SPINAL CORD THAT GIVE RISE TO A SPINAL NERVE. THERE ARE
8 CERVICAL
12 THORACIC
5 LUMBAR
1 COCCYGEAL/CAUDAL
```
63
what are the cervical and lumbar enlargements?
its buldges where the nerves at these locations supply both sensory information from and motor information to, the upper and lower limbs. the buldges are needed for the increases numbers of nerves in these areas.
64
what is the conus medullaris?
end of the spinal cord, located at L1/L2.
65
what is the cauda equina?
"the horses tail", collection of spinal nerves caudal to the conus medullaris.
66
what is the filum terminal
funcitons in attachment or anchoring of the spinal cord to the coccyx.
67
what are the key structures of the spinal cord?
sensory nerve root, dorsal root ganglion, motor nerve root, and spinal nerve
68
name the path of the circuitry.
1. start with large diameter sensory fibres
2. small diameter sensory fibers
3. lower motor neurons
4. preganglionic autonomic neurons.
sometimes there are interneurons
69
what are the 3 functions of the spinal cord?
1. pathway for motor descending informaiton
2. pathway for sensory ascending information
3. reflex coordination (within the spinal cord segment)
70
what are 3 types of spinal neurons?
1. efferent motor neurons
2. projection internuncial neurons
3. interneurons.
71
define efferent motor neurons
lower motor neurons located on ventral aspect of cord.
alpha motor neurons innervate skeletal muscles
gamma motor neurons innervate muscle spindles
72
define projection (internuncial) neurons.
they travel between segments and sen axons from the spinal cord to the brainstem, cerebellum, brain
73
define interneurons
axons stay within the spinal cord gray matter and connect the anterior and posterior horns. they stay within the same segment, they establish local circuits- spinal reflexes, and reflex arc.
74
how is arterial blood supplied to the spinal cord.
each vertebral artery gives rise to an anterior and posterior spinal artery, the anterior artery travels along the midline, and the posterior arteries supply the posterior columns, posterior horns, and some of the lateral CST.
75
what is funiculus?
its a large group of nerve bibres in a psecific area. it consist of columns of white matter.
76
what is fasciculus?
a group of fibres from diverse origins arranged in smaller bundles within the funiculi
77
what is a tract?
its a group of nerves fibres from the same origin to the same destination
78
what is a pathway?
refers to the entire neuronal circuit for a specific function.
79
whats significant about the sizing of the dorsal median sulcus and the ventral median fissure?
the dorsal median is HUGE compared to the ventral median.
80
what is the lissauer's tract
posterior is in location
the spinal column and ascend or descend one or two spinal segments in this tract before penetrating the grey matter of the dorsal horn, where they synapse on second-order neurons.
81
describe 3 points related to the organization of gray matter
1. some parts os the spinal gray matter are always present
2. some parts of the spinal gry matter are only present at certain levels,
3. some parts of the spinal gray matter are emphasized at levels that make functional sense.
82
what spinal gray matter is present always?
substania gelatinosa and lissauers tract
83
what spinal gray matter is present at certain levels?
1. latteral horn (T1-L3(: preganglionic sympathetic neurons
2. preganglionic parasympathetic neurons
3. clarke's nucleus at the base of the dorsal horn
84
what spinal gray matter is emphasized at certain levels?
dorsal horn and ventral horn
85
where is there enlargements in the spinal cord?
in the cervical and lumonosacral regions
86
into how many sections/colymns is spinal white matter divided?
3.
dorsal
lateral ventral
87
the columns contain 3 different types of fibres that run in different directions are what?
ascending- composed of sensory tracts
descending- composed motor tracts
commissural (transverse)- connect opposite sides of the spinal cord.
88
how are white matter tracts organized?
somatotopically, (also extends to the rest of the CNS)
| strict relationship between where the tract/neuron is and the kind of information in conducts or mediates.
89
what is special about somatotopical organization?
when a specific area of the brian or spinal cord is injured, there are specific signs that can be explained by the damage to the specific neuron types.
90
what are some general properties of tracts?
they are anatomically and physiologically distinct.
most tracts consist of a chain of 2-3 neurons
neurons in tracts usually but not always decussate at some point in the pathway between the spinal cord and brain.
(decussate= cross over to the other side)
91
what are the 3 pathways of the column that have clinical significance?
1. posterior columns- touch and position
2. spinothalamic tract- pain and temperature
3. lateral corticospinal tract- voluntary movements.
92
what are the 4 general features of the ascending pathways?
1. sensory tracts- chain of neurons carrying information form receptors to the cerebral cortex
2. preimary neron aways enters the spinal cord via the dorsal root
3. the ell body of the primary neuron is always in the dorsal root ganglion
4. sensory info crosses the midline (decussates) to the contralateral side.
93
describe the 1st order neurons of the ascending pathway.
soma (ell body) of these neurons occupy dorsal root ganglia
94
describe the 2nd order neurons of the ascending pathway
soma of these neurons occupy ipsilateral gray matter and their axons project to the contralateral thalamus
95
describe the 3rd order neurons of the ascending pathway
project from the thalamus to the somatosensory cortex
96
what is the significance of the posterior (dorsal) column-media leminiscal pathway
it conveys information about touch and limb position,
its located at the most dorsal aspect of the spinal cord.
its composed of large diameter fibres
its comprimised of fasiculus cuneatus and fasciculus gracilis.
97
what is the features of the spinothalamic pathway
it conveys information about pain and temperature, its located in the ventrolateral areas of the spinal cord white matter, and is composed of small diameter fibers.
98
what kind of neurons does the descending pathways have, and what does the descending pathway cause?
upper motor neurons that modify the activity of the reflex arc, and it causes the movement through lower motor neurons that leave the spinal cord to innervate muscle.
99
what are the characteristics of the corticospinal (pyrimiadal) tract?
fibers travel through the ventral pyramids of the medulla, and neurons located in precentral gyrus. the axons descend within the internal capsule. and most fibres cross over at the pyramidal decussation at the medulla-spinal cord junction.
100
name four other minor descending motor pathways and their major function
reticulospinal tract- locomotion and postural control
tectospinal tract- orienting the head/trunk towards visualand auditory stimuli
vestibulospinal tract- keeps center of gravity between two feet
raphespinal tract- pain modulation.
101
what are the effects of damage to the posterior columns?
impared trouch and position sense,
ipsilateral side
below the level of lesion
102
what are the effects of damage to the lateral corticospinal tract?
weakness, increased tone and reflexes
ipsilateral side
below the level of the lesion
103
what are the effects of damage to the spinothalamic tract?
impaired pain and temperature sense,
contralateral side,
beliw the level of the lesion
104
what are the effects of damage to the cross spinothalamic fibers?
impaired pain and temperature sense
both sides
at the level of the lesion
105
what are the effects of damage to the anterior horn?
weaknes, decreased tone and reflees, atrophy
ipsilateral side
at the level of lesion.
