E2 Flashcards
(309 cards)
1
Q
The gray matter of the brain/spinal cord consists of ______?
A
cell bodies + nuclei- functional part
2
Q
The white matter of the brain/spinal cord consists of _____?
A
axons - pathways for informational travel
3
Q
Association pathways connect what regions of the brain?
A
Different areas within the same hemisphere
4
Q
Commissural pathways connect what regions of the brain?
A
Both sides of the brain, but the same areas of each side (homotopic)
5
Q
Projection pathways connect what regions of the brain?
A
Connect specific areas to other areas or nuclei. Can be ascending or descending (sensory or motor)
6
Q
What is the difference between 1st, 2nd, and 3rd order neurons?
A
A 1st order neuron is the one coming out to the spinal cord where it synapses on neuron 2, which then goes up to the brain and synapses on neuron 3
7
Q
Afferent neurons carry _____ information
A
Sensory
8
Q
Efferent neurons carry ____ information
A
Motor (EFFerent, EFFect)
9
Q
What are the two groups of our conscious sensory information? What do they consist of?
A
Exteroceptive (Somatic (touch, pressure temp, pain) and telereceptors (vision and hearing), and proprioceptive (locomotor and vestibular labyrinth)
10
Q
What is the non-conscious component of sensory information?
A
Proprioception
11
Q
The corticospinal tract is the major …..
A
voluntary motor pathway
12
Q
Where do dorsal rootlets enter?
A
Shallow longitudinal groove (posterolateral sulcus)
13
Q
Where do ventral rootlets leave
A
Anterolateral sulcus
14
Q
In terms of spinal cord anatomy, what is unique about the cervical and lumbar regions?
A
Cervial has a region from C5 to T1 called the “Cervical enlargement”, this region supplies the upper extremities. Large because it controls a lot of things Similar for lumbar except it is L2 to S3 and it supplies lower extremities
15
Q
What is the pyramidal decussation? Where is it located. What is important about it?
A
It is a region at the top of the spinal cord where some nerve tracts cross over.
16
Q
throughout development, each spinal nerve retains its relationship with this mesoderm derived embryonic structure. What is this structure? What is the exception to this rule?
A
Somite. C1 is the exception because it typically has only a rudimentary dorsal root.
17
Q
What cord segment innervations the deltoid and supraspinatus? Biceps, brachialis? Triceps?
A
C5 C6 C7
18
Q
The corticospinal tract is located in what region of the spinal cord?
A
The lateral funiculus
19
Q
posterior column of medial lemniscus resides in what region of the spinal cord?
A
gracile and cuneate fasciculus
20
Q
Where is the lateral gray horn present in the spinal cord?
A
Thoracic region and first 2-3 lumbar.
21
Q
The cuneate fasciculus is present in what region of the spinal cord?
A
Cervical
22
Q
Why is the anterior horn bigger than the posterior?
A
The anterior horn is motor control, therefore this region has muscles to control and is larger because of that
23
Q
The anterior horn contains what?
A
Alpha and gamma motor neurons, and where the cells of origin of the fibers of ventral roots
24
Q
Intermediolateral gray horn is between the dorsal and ventral gray horns, what does it contain?
A
In the thoracic and upper lumbar regions it contains preganglionic cells for the autonomic nervous system. These neurons give rise to sympathetic axons that leave via ventral root and travel to the sympathetic ganglia via white rami. At S2, S3, S4 are sacral parasympathetic neurons, which leave within the sacral ventral roots, and leave to synapse on neurons in pelvic viscera
25
How can you tell the difference between Cervical, thoracic and lumbar cross sections of spinal cord?
Cervical: Dorsal grey column is narrow and ventral is broad Thoracic: Dorsal and ventral columns are narrow and lateral horn present Lumbar: Broad dorsal and ventral columns
26
Ascending and descending pathways have a defined location in \_\_\_\_\_
White matter
27
Ascending and descending pathways have a defined location in \_\_\_\_\_
White matter
28
The posterior column of the spinal cord consists of the... (2 things)
Gracile and Cuneate fasciculus
29
The posterior column of spinal cord is responsible fo transmission of..
Fine/discriminative touch, conscious proprioception and vibration
30
The anterolateral system contains the... (2 tracts)
Spinothalamic and spinoreticular tracts
31
The anterolateral system is responsible for the ...
Transmission of pain, temperature, non-discriminative touch
32
What arteries give rise to to the arteries of the spinal cord?
Vertebral and radicular
33
What are the arteries of the spinal cord and where are they anatomically?
Anterior spinal artery and two posterior spinal arteries. In the ant/post. They form a spinal arterial plexus around the cord
34
Explain the knee jerk reflex.
It stretches the patellar tendon which stretches the quadriceps muscle. 1a endings are excided and excite alpha motor neurons of quadriceps, they contract. The hamstring muscles are inhibited via reciprocal inhibition
35
Explain clasped knife reflex
If a person has a certain pathologic condition, resistance of muslces is greatly increased. If enough force is applied, the arm/leg will fold tight like a knife
36
What are two main functions of the nasal cavity?
Modifies air and helps smell things.
37
What are the nasal cartilages?
Septal and Alar. Lateral nasal is fuse with Septal.
38
What is the role of nasal conchae?
They increase surface area of the inner nose
39
What are boundaries of nasal cavity?
Palate, Maxillary bone, Palatine bone, Nasal bone, frontal bone, Ethmoid (cribiform plate), sphenoid
40
If a patient presents with a clear fluid coming from the nose after an injury to the nose, what could have happened and what could occur if not treated?
The cribiform plate could be fractured leaking CSF down the nasal cavity. Meningitis could develop.
41
What are the names of the 3 concha and how can you identify them? During a nose exam, which can you not see?
Superior, middle and inferior. Superior is highest and smallest. Cannot see superior
42
What bones form the superior, middle, and inferior concha?
Superior and middle are part of ethmoid, while inferior is a separate bone
43
What is the space above the superior concha called?What is present there?
Spheno-ethmoidal recess. Olfactory foramina and spehnoid air sinus
44
What is the sensation type of the nose and where does it derive? What are the nerve branches named?
Somatic Sensory. V1 and V2. V1- anterior ethmoidal nerve. V2- Nasal branches, Nasopalatine N.
45
The mucous glands of the nose are what type of innervation via what nerve?
Visceral motor, parasympathetic. Via Facial nerve by pterygopalatine ganglion
46
Irritation of the ptergopalatine ganglia can cause an increase in...
Mucous and tears
47
What arteries supply the nasal cavity?
Sphenopalatine A from Maxillary. Ant and Post ethmoidal A from Opthalmic. Facial A branches.
48
What veins drain the nasal cavity?
Ethmoidal V drain to opthalmic, other to pterygoid venous plexus, facial vein.
49
Why can a nosebleed produce significant amounts of blood? How do you know if it is arterial or venous?
Anastomoses. Would spurt if it was arterial.
50
What are the names of the paranasal sinuses? Which one, if blocked via infection can spread to the orbit?
Frontal, ethmoid, sphenoid. Ethmoid.
51
Do babies have sinuses?
Nope
52
What is the largest sinus? What is the clinical association with it?
Maxillary sinus. Roots of maxillary teeth are in floor of sinus and this can be damaged by a tooth extraction.
53
What nerve supplies the Max sinus and teeth?
V2. A sinus infection can feel like a tooth ache.
54
Describe development of primary and secondary palate
Primary palate is anterior to incisive foramen and formed by union of Medial Nasal Processes. The secondary palate is posterior to incisive foramen and is formed by fusion of the maxillary processes
55
Explain how a posterior cleft palate forms, and an anterior cleft palate (cleft lip).
PCP forms from the maxillary processes on both sides not fusing. ACP forms from medial nasal process AND maxillary processes not fusing
56
What is the function of the soft palate?
Flap valve that closes off the nasopharynx during swallowing
57
What are the muscles of the soft palate?
Tensor palati, Levator Palati, musculus uvuli, palatoglossus.
58
When you contract these muscles of the soft palate, it opens the auditory tube and equilibrates pressure. What are these muscles
Tensor and Levator Palati
59
What supplies blood to the palate?
Descending palatine A (from maxillary A) this dovodes tp hard palate GREATER PAL A. and soft palate LESSER PAL A Sphenopalatine artery passes through the incisive foramen Ascending palatine A. (from Facial)
60
What innervation is the palate? What nerves do this.
ALL V2 (somatic sensory) Greater palatine N, nasopalatine N (both to hard), lesser palatine N (soft)
61
Where does lymphatic drainage of palate go?
Retropharyngeal nodes
62
The palatoglossal arch is the site of the... What is the innervation of these regions?
Oropharyngeal membrane, boundary between the Oral cavity and pharynx. The oral cavity is somatic sensory. Pharynx is visceral sensory
63
Muscles of the palate are under what type of control?
Branchiomotor, voluntary control.
64
What muscles push the bolus back when contracting?
Mylohyoid and Styloglossus. Note: this is voluntary
65
What is the mistake to do when eating food? Why?
Talk. Palate goes down, and nasopharynx is no longer sealed off. This can put food into your nasal cavity.
66
What nerve/artery can be damaged in a tonsillectomy?
Glossopharyngeal nerve, tonsillar branch of facial A.
67
Where does the lymphatic drainage of the palatine tonsils go?
Deep cervical nodes.
68
What are the veins of palatine tonsils?
Pharyngeal plexus to facial lingual or inferior jugular.
69
What muscles form the tonsillar bed?
Superior constrictor of Pharynx and styloglossus
70
What are the names of the branches of the Facial A that supply palate and tonsils?
Ascending palatine artery and tonsillar branch
71
If looking at a sagittal view of the submadibular region, what is the order of muscles from top to bottom?
Genioglossus, geniohyoid, mylohyoid, digastric
72
What is ludwig's angina?
Infection of submandibular space (floor of mouth), often due to an abscessed mandibular tooth
73
What is the sulcus terminalis and where is it located? What does it divide?
It is the "V" shape groove that divides tongue into Ant 2/3 of tongue, and post 1/3. Ant is somatic sensory, post is visceral sensory.
74
What is the foramen cecum and what is its significance?
It is the pit in the middle of the sulcus terminalis, which is the site of invagination of the thyroid gland
75
What innervates the muscles of the tongue?
CN XII
76
What is the clinical sign of a patient with a damaged hypoglossal nerve (Lower motor neuron)?
The tongue protrudes and deviates TOWARD the lesion due to unopposed action of the genioglossus muscle
77
What way will the tongue deviate in an upper motor neuron lesion?
Away from side of cotrical lesion
78
What is the lymphatic drainage of the tongue? (3 regions)
Tip of tongue - submental nodes Rest of Ant 2/3 - submandibular nodes and deep cervical nodes Post 1/3 of tongue - deep cervical lymph nodes
79
What is the clinical sig. about lymph vessels?
They cross the midline of the tongue, so the lesion may spread to the opposite side
80
What is sensory innervation of the tongue?
Ant 2/3 - V3 (touch) and CN7 (taste) (Lingual N. and Chorda Tympani) - the Lingual hitchhikes with the Chorda Tympani Post 1/3- CN 9 Ant to epiglottis - Vagus
81
The facial nerve has three branches in the Facial Canal, what are they? What do they do and what type of innervation are they?
Greater Petrosal N. (Visceral motor to parasymp of lacrimal and mucous glands. Visceral sensory to nasopharynx) Stapedial N. - Branchiomotor to stapedius Chorda Tympani - Taste to ant 2/3 of tongue, visceral motor parasymp to submandibular, sublingual, and salivary glands
82
What is the name of the fissure that chorda tympani travels in? What else travels here?
Petro- tympanic fissure , Ant. Tympanic A.
83
Severing the lingual nerve in the floor of the mouth can by an impacted tooth or a fall can cause what?
Severing the lingual nerve + hitchhiking fibers of CN 7 Will lose general sensation to Ant tongue and taste to Ant 2/3
84
Where does CN 7 exit the skull? Where does it leave in the skull internally?
Stylomastoid foramen - internal auditory meatus
85
The parasympathetics of CN7 go to what ganglia? Then to where?
Pterygopalatine to lacrimal gland, mucous, nose palate. Some also go to submandibular ganglia
86
A tumor at the internal auditory meatus (an acoustic neuroma) produces what effects by blocking what nerve(s)?
Blocks CN 8 and 7. 8 will cause auditory/vestibular deficits 7 will have all symptoms present - facial paralysis, hyperacousia, loss of taste to ant 2/3, decrease secretion of lacrimal
87
What is the clinical presentation of damage to CN 7 at the stylomastoid foramen or parotid gland?
ONLY Facial paralysis NO loss of taste, hyperacousia, decrease in secretion note: CN 8 not effected here
88
What two vessel / nerve run in the temporal fossa?
Superficial temporal artery and Auriculotemporal N (V3)
89
What A. supplies blood to the nasal cavity, calvarium, oral cavity, middle ear?
Maxillary A.
90
The maxillary A. cannot be ligated, so to stop a bleed branches must be \_\_\_\_\_\_
Cauterized
91
What are the branches of the Maxillary A.?
1st part Deep Auricular A, Ant Tympanic A, Middle Meningeal A, Accessory Meningeal A, Inferior Alveolar A 2nd part: Deep Temporal A, Pterygoid A., Masseteric A, Buccal A, 3rd part: Post Sup Alveolar A, Descending Palatie A, Artery of Pteryoid canal, Sphenopalatine A, Infraorbital A
92
Damage to the middle meningeal artery can cause...
Epidural Hematoma, Uncal herniation, Tonsillar herniation
93
Why can infections spread from the teeth, nasal cavity, palate, to brain?
Because the pterygoid plexus has anastomoses with veins that drain to the cavernous sinus
94
What are the three ligaments of the Temporo-madibular joint?
Temporo-mandibular ligament, sphenomandibular ligament, stylomandibular ligament
95
The muscles of mastication are all what innervation?
Branchiomotor by V3
96
Which direction does the lateral pterygoid pull the disc when opening mouth?
Antieriorly
97
When the jaw is stuck from injury, what is it stuck on?
Articular tubercle
98
Trigeminal nerve damage how does the jaw deviate?
Goes TOWARD paralyzed side when patient opens mouth due to unopposed action of lateral pterygoid muscle
99
What nerve is involved in the jaw jerk reflex?
Senory and motor V3
100
What germ layer does the parotid gland bud from?
Ectoderm
101
What are accessory parotid glands?
Incomplete joined parotid glands - shows no clinical significance
102
A viral infection of the parotid can lead to pain in what region due to compression of what nerve?
Pain in ear from Auriculotemporal nerve compression (V3)
103
What is the innervation of Parotid?
Visceral motor parasymp of CN 9
104
Where is conscious sensation perceived? What are the two types of sensation?
At the cerebral cortex. Exteroceptive (somatic receptors include touch, pressure, heat, cold, pain) and proprioceptive
105
Where is non-conscious sensation perceived? What are the two types of sensation?
It is not perceived, it is routed to the cerebellum. The two types are proprioception and interoception (involves unconscious afferent signals)
106
In general, what is the purpose of an ascending pathway?
To take sensory information up to the brain.
107
What are the two major pathways for somatic sensory perception?
Posterior (Dorsal) Column - Medial lemniscal pathway Spinothalamic (anterolateral) pathway
108
Where does the Posterior dorsal column pathway decussate?
At the medulla (cunea nucleus, cuneate gracilis)
109
Neurons are post-mitotic cells, meaning....
If they die they cannot be replaced
110
Name the three meninges surrounding the brain and spinal cord
Dura, subarachnoid space, and pia
111
Is the dura of the brain continuous with the dura of the spinal cord?
NO
112
What is the role of the dural septa in the brain?
It divides the brain and provides support and protection.. Protects the brain against sudden and violent head movements
113
What does the falx cerebri separate?
The two cerebral hemispheres
114
What does the tentorium cerebelli separate?
The cerebellum from the cerebrum
115
The midbrain fits through a notch formed by the tentorium cerebelli, what is it called?
Tentorial incisure
116
Infratentorial lesions are more common in children or adults?
children
117
Supratentorial lesions are more common in children or adults?
Adults
118
What is the big purpose of the dural venous sinuses?
A way to circulate and return CSF to general circulation
119
Describe the arachnoid matter.
A delicate membrane between pia and dura mater where all major blood vessels lie in this region (in the subarachnoid space). Making this space common for hematomas
120
Name the 4 major cisterns. What fluid is in the cistern?
Cerebellomedullary cistern, pontine cistern, interpenduncular cistern, lumbar cistern. CSF
121
What is the role of arachnoid villi? What can happen to these and what is the clinical condition?
They reabsorb CSF from subarachnoid space to superior sagittal sinus. They can become calcified, often in the elderly, and this can lead to herniations and hydrocephaly
122
Describe pia mater. What is unique about arteries that dive into the inner brain from the pia?
Thin, highly vascularized layer that covers closely to the surface of the brain and spinal cord. The pia covers the arteries when they dive to the inner brain (Virchow-Robin Space)
123
Describe the flow of CSF with regards to the portion that extends to the eye. What is the clinical condition that can result from increase CSF pressure?
The CSF flows down but does not necessarily have a way back. An increase in pressure can squeeze the venous return and lead to papilladema
124
What is the largest ventricle?
Lateral ventricle
125
What is the name of the 4 parts of the lateral ventricle?
Frontal (ant.) horn, body, temporal (inf.) horn, occipital (post.) horn
126
What separates the lateral ventricles?
Septum pellucidum
127
What are the walls of the third ventricle formbed by?
Thalamus and hypothalamus
128
What are the outpockets of the 3rd ventricle?
Infundibular, optic, pineal, suprapineal recesses
129
What connects the 3rd and 4th ventricles? Why is this important?
Connects to the 4th via the cerebral aqueduct of sylvius, which is very prone to blockage. (pineal tumor)
130
What forms the 4th ventricle?
Cerebellum and pons and medulla
131
What is a big role of the circumventricular organs?
to tell the brain what is in the blood so the brain can respond appropiately
132
What is the role of pineal body?
Secretion of melatonin, regulation of circadian rythyms
133
What is the role of the organum vasculosum of the lamina terminalis?
Sensory area that supplies input to other brain regions, contains osmoreceptors sensitive to Na+ and osmotic pressure in blood
134
What is the role of the median eminence?
Secretion of hormones
135
What is the role of subcommissural organ?
Produces transthyretin
136
What is the role of the pituitary gland (neurohypophysis)
Secrete oxytocin and vasopressin
137
What is the area postrema and the role in the body?
Detect toxins in blood, vomit center. Responsible for sea and travel sickness
138
What secretes CSF? Where does this occur?
Choroid plexus. Lateral and 4th ventricles
139
Where is CSF found?
Ventricles, subarachnoid space, cisterns (these are all continuous with each other
140
What is typically the state of CSF in the body?
Clear, sterile
141
What does pink/red CSF suggest?
Blood in the CSF (could be a bad tap)
142
What does yellow color and spontaneous clotting?
Could mean increased bilirubin from RBC lysis, increased protein, MS
143
What does cloudy or white CSF suggest?
Could suggest infection, bacterial meningitis, which would lead to increased protein and decreased glucose
144
What does clear to cloudy CSF suggest?
Aseptic meningitis, would have normal values for protein and glucose so less likely to be bacterial
145
Explain the circulation of CSF.
CSF is formed in the lateral ventricles by choroid plexus and passes through the interventricular foramina into the third ventricle. Then thru the cerebral aqueduct into the 4th ventricles where more CSF is added. Then thru the foramen of magendie and foramina of luschka apertures into the cisterna magna and pontine cistern. From these basal cisterns, the fluid slowly moves thru the tentorial notch, up and over the cerebral hemisphers thru the arachnoid villi and into the superior sagittal sinus. Some CSF moves from the cisterns around the 4th ventricle to the subarachnoid space, then to the spinal cord
146
How does CSF move through the CNS?
Through arterial pulsations, respiratory movements - they cause a constant ebb and flow
147
What is the equation for cerebral perfusion pressure?
CPP= mean arterial BP minus intracranial pressure
148
If pressure increases in the skull, what compensatory mechanism will occur?
CPP will decrease by decreasing blood flow pressure
149
What is a subfalcine herniation?
A herniation of brain matter between the lower part of the falx cerebri and the corpus callosum
150
What is an uncal herniation?
Herniation of the uncal region of the temporal lobe thru the tentorial notch
151
What symptoms can arise from an uncal herniation?
Contralateral motor weakness if compression of the ipsilateral crus cerebi. If compressed against tentorium cerebelli at the contralateral crus, then it will be ipsilateral motor weakness Decreased consciousness, pupillary dilation on side of herniation due to compression of CN3 parasymp.
152
What symptoms can arise from tonsillar herniation? What is a tonsillar herniation?
The tonsil region going through the foramen magnum, squeezing medulla oblongata. Significant decrease in level of consciousness, change in vital signs. Can cause death from cardiac/respiratory failure
153
A subarachnoid hemorrhage can be spontaneous, how does this occur?
Rupture of berry aneurysm at Circle of Willis.
154
What are the cardinal symptoms of a subarachnoid hemorrhage?
Sudden onset of severe headache, stiff neck, altered consciousness
155
What region of the skull is the worst to fracture?
The base of the skull
156
What is the shape of an epidural hematoma on a CT/MRI. What common A. ruptures in this situation?
Lens - Middle Meningeal A
157
What is the shape of an subdural hematoma on a CT/MRI. What common vessel ruptures in this situation?
Crescent shaped - Bridging veins
158
TBI is a risk factor for what diseases?
Alzheimers, Parksinsons, ALS
159
What is chronic traumatic encephalopathy (CTE)? Symptoms?
Repeated TBIs over a period of time. Memory loss, paranoia, depression, ataxia
160
What are the two types of hydrocephalus?
Non-communicating and communicating AKA obstructive vs non-obstructive
161
What is the difference between non-communicating and communicating hydrocephalus?
Non-communicating means CSF flow out of one or more ventricles from 4th to subarachnoid is blocked. Communicating means too much CSF is made ornot enough is absorbed
162
Anatomically speaking, what is the common culprit in non-communicating hydrocephalus? What condition can cause this?
Aqueduct of sylvius. A tumor.
163
Idiopathic intracranial hypertension is what?
Increased ICP with no apparent cause on imaging.
164
In a patient with ICP (idiopathic intracranial hypertension) what is a common symptom. What provides relief almost immediately?
Daily pulsatile headaches, possible visual disturbances. A lumbar puncture will provide instant relief.
165
What is the common patient characteristics of a person with ICP?
Female, obese, XS Vit A, estrogen BC, tetracycline antibiotics
166
What is normal hydrocephalus? What group is this prevalent in?
In elderly adults, it can be due to an imbalance between production/reabsorption of CSF, but can occur without na increase in ICP
167
What are the symptoms of normal hydrocephalus?
Gait difficulty, cognitive disturbance, urinary incontinence
168
Where does the spinothalamic pathway decussate?
At the level it enters
169
What information does the cuneate fasiculus carry, and what vertebral level?
Starts at T6, carries anything T6 up like the arm, upper trunk, neck, occiput
170
The medial portion of the gracile fasiculus carries information from what region?
Legs and lower trunk
171
Where do 1st order afferents of the posterior column medial lemniscal pathway terminate?
Gracilis and cuneatus in medulla oblongota
172
Where do 2nd order afferents of the posterior column-medials lemniscal pathway terminate?
Thalamus
173
Where do 3rd order afferents of the posterior column-medials lemniscal pathway terminate?
Somatosensory cortex
174
What is the function of the medial lemniscal pathway?
Conscious proprioception and discriminative touch
175
Disturbance of the posterior column pathway is common in what diseases? What are symptoms?
Demyleninating diseases like MS. Classic symptom is sensory ataxia and positive Romberg sign
176
Describe the somatotopic organization of the anterolateral tract.
Like an onion layer, the inner most is Neck, then arm, trunk, leg (outermost layer).
177
What are the three tracts in the anterolateral pathway?
Spinothalamic, spinoreticular, spinomesenphalic
178
What type of information does the spinothalmic tract carry?
Pain and temperature
179
Why do some axons of spinothalamic ascend/descend in Lissauer's tract before entering the central gray?
It provides a more coordinated response
180
Where do the 1st order neurons of the spinothalamic tract synapse onto the 2nd order?
In the dorsal horn (lamina 1 and lamina 5)
181
Are primary afferents of nerves that make up spinothalamic tract myelinated?
No
182
What level of afferent decussates in the spinothalamic tract. Where does it do this?
The secondary afferent decussates at the level it enters the spinal cord
183
Where do they anterior spinal thalamic tract and the lateral spinal thalamic tract merge? What does each one contribute to in terms of sensation. What else hitchhikes with these fibers in the head region?
They merge in the brain stem and form the spinal lemniscus. The ASTT contributes touch. LSTT is temperature and pain (mediating noxious and thermal sensation separetly) Trigeminal nerve
184
All input from the spinothalamic tract end up where?
Somatosensory cortex
185
In the homunculi, what is the relationship between size and sensory function?
The things with more important sensory need (hands, face) occupy a larger area of the somatosensory cortex
186
Describe the spatial relationship of the somatosensory cortex and the motor cortex
The somatosensory cortex is behind the gyrus (in the back) and then motor cortex is in front of gyrus
187
What incident often leads to Syringomyelia? What is it and what clinical presentation occurs.
Often occurs in car crashes. Characterized by a cyst in or beside central canal in cervical region, spinothalic fibers are obliterated. Pts present with dissociated sensory loss in a arms and across upper chest - "cloak and arms"
188
What lamina does the spinoreticular tract arise from?
6-7
189
Where does the spinoreticular tract terminate -
Medullary-pontine reticular formation
190
What is the role of the spinoreticular tract?
Arouses the cerebral cortex, inducing a wake state. It reports to the limbic cortex about the nature of a stimulus (pleasurable or aversive)
191
Where does the spinomesencephalic tract arise from?
Lamina 1 and 5
192
Where, in the brain, does the spinomesencephalic prokect to?
Periaqueductal gray and the superior colliculus
193
What is the role of the spinomesencephalic tract?
the regulation of pain
194
You step on a nail with your foot, explain the general way the anterolateral tract will handle this.
Spinothalamic - Something sharp on foot Spinoreticular + Spinothalamic intralaminar projections- this sharp thing hurts - OW Spinomesencephalic - It will be okay, it will feel better
195
There are also three pathways that run to the cerebellum, what are these called?
Spinocerebellar pathways: Posterior and anterior spinocerebellar tracts, cuneocerebellar tact
196
Yea just know this table, I guess
Do et
197
Where does the posterior spinocerebllar tract begin to exist?
At the Clarkes nucleus (medial part of lamina 7), which begins at about L2
198
The posterior spinocerebellar tract is principally concerned with the ______ leg
Ipsilateral
199
The posterior spinocerebellar tract project ipsilaterally to medial zones of the cerebellum through the \_\_\_\_\_\_
inferior cerebellar peduncle
200
The cuneocerebellar tract is principally concerned with \_\_\_\_\_\_\_\_
Ipsilateral upper thorax and arm
201
Where do fibers of the cuneocerebellar tract terminate
A nucleus in the medulla called the lateral cuneate nucleus
202
Axons of the cuneocerebellar tract projects to the cerebellum through the \_\_\_\_\_
Inferior cerebellar peduncle
203
The anterior spinocerebellar tract is different from the posterior spinocerebellar tract in 3 major ways, what are they?
Its sensory information is more compolex due to it receiving input from more than just golgi tendon organs, like cutaneuous receptors and spinal interneurons.
The tract crosses at the level of spinal cord it enters
The route to cerebellum is different, it enters the cerebellum via the superior cerebellar peduncle
204
Two-point discrimination and vibration is detected by what pathway?
Posterior column - medial lemniscal pathway
205
The three sensory systems that provide cerebellum input to maintain truncal stability are:
What clinical test tests for this functionality
Vision, proprioception, vestibular sense.
Romberg
206
Name where this lesion could be:
Sensory deficit to one half of body (right side of body)
Somatosensory cortex: deficit contralateral to lesion. discriminative touch and join position sense affected, contralateral neglect is a CORTICAL SIGN because awareness of our bodies as being part of ourselves is integrated and processed in the cortex
Thalamic region: Deficit contralateral to lesion
207
Name where this lesion could be:
Sensory loss to right side of body except face. Sensory loss to face on left side of body
Lateral Pons / Lateral medulla
- contralateral anterolateral and IPSILATERAL trigeminal pathway
Loss of pain and temperature in body opposite of lesion
Loss of pain and temperature in the face on side of lesion
208
Name where this lesion could be:
Sensory loss to right side of body except face
Medial medulla
Lesion involves the medial lemniscus, causes contralateral loss of vibration and joint position sense
209
Name where this lesion could be:
Sensory loss on lower arm, hands or leg
In a peripheral nerve.
Can be distal symmetric polyneuropathy causeing a glove and stocking distribution
Or it can be an isolated nerve injury
210
What is Tabes Dorsalis caused by? What is it?Symptoms?
Tertiary syphillis
It is inflammation of dorsal roots resulting in degeneration of dorsal columns of spinal cord
PT will present with bilateral loss of fine touch, vibration, and conscious proprioception. PT may present with Romber or Lermittes sign
211
What is Lermitte's sign
Electric like shock that occurs when there is damage to the dorsal columns in the cervical areas of the spinal cord
212
A deficiency in Vit B12 intake or metabolism can cause ...
Who may have this type of disorder?
Subacute combined degeneration:
Spinal cord degeneration via demyelination and loss of axons.
Vegans
213
MS can involve demyelination of ____ pathway
CNS
214
A lesion of the postcentral gyrus can induce what in patients?
Sensation loss, paresthesias may be present,
Pt will lose two-point discrimination, difficutly localizing painful stimulation precisely, astereognosis (loss of size/shape/texture discrimination), agraphesthesia
215
The parasympathetic nervous system originates where?
Brain stem (CN3,7,9,10) and sacral region of spinal cord
216
Preganglionic neurons of the parasympathetic nervous system have ____ axons
Long
217
Preganglionic neurons of the sympathetic nervous system have ____ axons
short
218
The sympathetic nervous system orginates where?
Thoracic and lumnar cord (T1 - L3)
219
Fibers of the autonomic nervous system travel down what tract/pathway?
Central Autonomic Pathway
220
What is referred pain? Where would one experience referred heart pain?
Poorly localized pain. T1-T4 dermatomes mainly left side
221
What is the great voluntary motor pathway? Where do 40% of its fibers take origin from?
Corticospinal tract.
Precentral gyrus
222
What is the path of the corticospinal tract?
Descends through the corona radiata and posterior limb of the internal capsule to reach the brainstem.
Continues through the crus of the midbrain and the basilar pons to reach the medulla oblongata
Forms the pyramid
223
The 3 major descending motor systems we focused on are the..
Lateral and anterior corticospinal tracts and the rubrospinal
224
What is the difference between an upper motor neuron and a lower motor neuron?
An UMN is a neuron projecting from the brain or spinal cord. They form synapses on LMN in the anterior horns of grat matter in the spinal cord or brain stem.
LMN project from the CNS to various places/muscles
225
Where does the corticospinal tract start?
Primary motor cortext (Brodmann 4)
226
Explain the decussation of the corticospinal tract.
85% of fibers dessucate at the pyrimidal decussation (end of medulla), and forms the fibers of the lateral corticospinal tract. The remaining fibers form the anterior corticospinal tract, which decussate when they come out of the spinal cord
227
Where does the rubrospinal tract start? What does this suggest about its function?
It begins in the red nucleus of the brain stem. This means it does not contribute to higher level brain activity
228
Where does the rubrospinal tract decussate?
At the ventral tegmentum
229
What does the rubrospinal tract do?
Integrates motor information and influences muscle tone, inhibits some voluntary movement of body
230
Need to learn this: anatomy of the anterior gray horn
231
What is the unique property of lateral cortico spinal tract neurons when they synapse upon the alpha and gamma motor neurons of limb muscles?
Fractionation. They can selectively activate small groups of neurons for fine control
232
Differentiate alpha and gamma motor neurons
Alpha motor neurons supply the extrafusal fibers, and are the main force generators, while gamma motor neurons supply the intrafusal fibers of neuromuscular spindles which contribute to fine motor regulation
233
What is the purpose of renshaw cells?
They provide a signal that a muscle has been used enough and pulls back. Limits the activity of contraction of alpha motor neurons
234
What are the first neurons to be activated by the LCST during voluntary movements?
1A inhibitory internuncials
235
Compare and contrast clinical presentations of UMN lesion vs LMN lesion
236
What is the BIG difference between a UMN lesion vs LMN lesion
LMN lesion = FLACCID PARALYSIS
UMN lesion = SPASTIC PARALYSIS
237
Hyperreflexia is characteristic of a ____ lesion
UMN
238
Here is a chart to memorize if you have the time
239
A pt presents with unilateral face, arm, and leg weakness on the right side of the body. No somatosensory symptoms were noted. Where could the lesion be?
Corticospinal fibers between cortex and medulla (internal capsule, pons, cerebral peduncle).
The lesion would be above the pyriamidal decussation so the symptoms would be contralateral to the lesion
240
A pt presents with unilateral face, arm, and leg weakness on the right side of the body. Somatosensory symptoms were noted. Where could the lesion be?
Primary cortex damaged possibly dude to stroke or tumor, trauma
241
A pt presents with unilateral arm and leg weakness on the right side of the body. Where could the lesion be?
Arm and leg region of the motor cortex, and the cortical spinal cord below medulla and above C5. If the spinal cord was damaged below C5, then there would be some arm sparing.
Spinal cord may also have brown-sequard
242
A pt presents with unilateral face, arm weakness on the right side of the body. Where could the lesion be?
Face and arm areas of the motor cortex. The lesion is contralateral. Could have brocas aphasia if occured in dominant hemisphere.
Commonly caused by middle cerebral artery infarct
243
Unilateral arm weakness / paralysis
Could be peripheral nerve supplying arm or damage to the motor cortex region for the arm.
Could differentiate based on differences between UMN lesion and LMN lesion
244
Unilateral leg weakness or paralysis
Leg area of motor cortex / lateral corticospinal tract below T1 / peripheral nerves supplying leg
245
Unilateral face weakness
Could be Bells palsy CN 7 (ipsilateral)
If forehead spared, could be lesion in genu of internal capsule or lesion in motor cortex (contra)
246
Bilateral arm weakness or paralysis
Medial fibers of both lateral corticospinal tracts, could be an anterior artery infarct
247
Bilateral leg weakness or paralysis. Where is the lesion?
Bilateral leg areas of motor cortex, lateral corticospinal tracts below T1. Cauda equina syndrome
248
Bilateral arm and leg weakness. Where is the lesion
Bilateral arm and leg areas of primary motor cortex, bilateral lesions of corticospinal tracts between medulla and C5, peripheral nerve and muscle disorders that affect all four limbs
249
Where does spinal muscular atrophy occur? What is the name of this?
Congenital degeneration of cells anterior horns of spinal cord. Pts presents with diffuse proximal weakness and decreased deep tendom reflex
Werdnig Hoffman Disease
250
Amyotrophic lateral sclerosis (ALS) results in ...
Progressive loss of anterior horn cells and corticospinal tract. Patients will present with both LMN and UMN symptoms.
251
What can result from occlusion of anterior spinal artery?
UMN deficit below lesion due to corticospinal tract
LMN deficit at level of lesion (anterior horn)
Loss of temp and pain sensation below lesion (spinothalamic tract)
252
What is cauda equina syndrome?
Compression of spinal roots at L2 and below often due to disc herniation. Gives the effect of saddle anesthesia
253
Describe poliomyelitis
Due to polio virus infection, causes destruction of cells in anterior horn. Present with LMN signs, asymmetric weakness, hypotonia, flaccid paralysis
254
What is brown-sequard?
Caused by damage to one half of the spinal cord. Presents with Ipsilateral loss of all sensation at level of lesion, ipsilateral LMN signs at level of lesion. Ipsilateral UMN signs below level of lesion (corticospinal tract damage). Ipsilateral loss of proprioception, vibration, light touch sense below level of lesion, contralateral loss of pain, temp, non-discriminative touch 1 -2 levels below the lesion due to spinothalamic damage
255
Compare and contrast AMP/KA and NMDA channels
Compare - Both have glutamate binding sites, permeable to Na and K
Contrast- NMDA is also Ca perm., NMDA also has a binding site for glycine and both sites (gly and glu) must be bound and open for functioning, NMDA has a binding site for Mg in the pore thay must be removed for functioning
256
What direction is the normal driving force for Mg
Inward
257
explain the cascade of an NMDA channel being activated
binding of glu and gly opens the NMDA channel, where Mg binds to the pore.
The cell membrane is depolarized via temporal summation of EPSPs, reducing driving force for Mg and allowing current flow. Mg leaves pore.
258
Explain the cascade of how cytotoxic edema occurs
Some anoxia, aglycemic event, leads to low oxygen and glucose, so no ATP production.
Primary active transport fails and ion gradients begin to break down.
Potassium gradients in particular are messed up, and the neurons depolarize to threshold and being firing APs at high rate. This releases a lot of Glu.
Depolarization and Glu present activated NMDA channels
Additionally in low ATP levels, Ca regulation is messed up. Lipases and proteases are abnormally activated and free radicals form.
Cytotoxic edema from massive ion influc and impared volume regulation
259
What is vasogenic edema?
When protein gets in the brain and brings H2O with it increasing ICP
260
Nociceptors are...
Free nerve endings
261
What type of transduction mechanisms do somatosensory receptors use?
Stretch gated ion channels, temp sensitive channels (TRP), can also be stimulated by chemical signals
262
What is the difference between Alpha gamma and C nociceptors?
Alpha gamma is small diameter and myelinated. They responds to Pain and temp.
C is unmyelinated and small diamter. They respond to pain, temp, and itch
263
If a cell is lysed by injury, what ion leaks to activate nociceptors?
Potassium
264
What chemicals sensitize nociceptors?
Arachidonic acid, prostaglandins, leukotrienes, substance P
265
What is divergence?
Axon from single neuron branches many times froming synaptic contacts with multiple target cells. Allows for large recruitment of signals
266
What is convergence?
Multiple presynaptic neurons merging on a single neruon. This allows for integration among many sources of information (retina)
267
Are most neurons in the CNS spontaneously active?
Yes
268
What is presynaptic inhibition?
Regulation of a signal before the synapse
269
What is disinhibition?
Removing the inhibition of something inhibitory. If X is inhibiting Y, well Z can inhibit X. So the inhibition is lifted. Net excitatory
270
What is lateral inhibition?
A inhibitory receptive field made by interneurons. It is to enhance detection of CONTRAST by creating larger detectable differences
Slide 10 of Neuronal Integration
271
What is feedback inhibition?
Requires a recurrent pathway where a product of the pathway inhibits an earlier step along the pathway
272
What is feedforward inhibition?
It requires a divergent pathway. It is useful for controlling antagonistic pathways. A good example is reflex pathways controlling antagonistic muscles
273
What is the reverberating circuit?
They allow for persistent activity in a system after the stimulus is gone. Can allow for information to be stored (short term memory). It is excitatory connections
274
Disruption of reverberating circuits can cause what?
Seizures. Normally feedback inhibition pathways regulate this
275
What are central pattern generators?
Rhythmically alternating activity can be created by several types of neural circuits. Example is during walking. Only one part will be active at once
(slide 15 neuronal integration)
276
What are the same 4 elements of every neuronal cell?
Input, integration zone, conduction zone, output zone
277
How do graded potentials encode signal strength?
Amplitude.
278
What occurs at the integration zone of a neuron?
Graded potentials are converted to all-or-none potentials (APs)
Other ion channels can impact signal response here
279
How do ion channels in the integration zone impact APs?
Certain calcium channels are open at certain times which can modulate the signals.
280
Contrast HVA and LVA (t-type) calcium channels.
HVA channels require strong depolarization (AP) for their activation
LVA open between resting potential and AP, and rapodly inactivate. Inactivation is removed at an IPSP
281
If an integration zone only had VGNa and K channels, what would the frequency look like?
282
If the integration zone contains HVA calcium channels and calcium activated potassium channels, what would frequency look like
Firing rate gradually slows causing slow adaptation
283
What can occur if an integration zone contains LVA VGCa? How?
Burst firing. T channels activate at membrane potentials below threshold. They open transiently and inactivate rapidly.
284
This is a good pic to understand
285
How do central pattern generators and T channels work together?
Once triggered active, they can remain active without active input because the T channels can modulate the APs while the pattern generator regulates the alternating APs
286
Abnormal T-type channels can cause \_\_\_\_, which can be treated with \_\_\_\_\_.
abscence seizures - ethosuximide
287
What are the 5 major subdivisions of adult human brain: what are the regions come from them?
Forebrain: Telencephalon, Diencephalon, Midbrain: Mesencephalon, Hindbrain: Metencephalon, Myelencephalon
T: Cerebral Hemispheres - cerebral cortex, subcortical white matter, basal ganglia, basal forebrain nuclei
D: Thalamus and hypothalamus
M: Cerebral peduncles, midbrain tectum, midbrain tegmentum
M: Pons cerebellum
M: Medulla
288
What is the one sense not processed in the thalamus?
Smell
289
What is the main role of the hypothalamus?
CNS center for regulation of autonomic and endocrine activity
290
What is the role of the superior and inferior colliculi?
Visual and auditory reflexes
291
A tumor of the pineal gland can lead to what?
Compression of the aqueduct of Sylvius, causing non-communicating hydrocephalus
292
What lobe of the cerebellum manages the input from vestibular system?
Flocculondular
293
What bridges the brain to the cerebellum?
The Pons
294
Pontine nuclei project (Ipsilaterally or contralaterally) to the cerebellum
Contralaterally
295
What does the medulla do?
Controls vital respiratory and cardiovascular centers
296
Long term alcoholism can damage this part of the hypothalamus, what is it?
Mamillary bodies
297
Where is the precentral gyrus anatomically? What is it? What is the brodmann number?
It is in front of the central sulcus and is the motor cortex. It is Brodman number 4
298
What is Brodmann area 8. Stimulation to this region causes what?
A lesion to area 8 produces what effect?
Frontal eye fields. Stimulation of 8 causes paired eye movements to the contralateral side.
An area 8 lesion on one side causes both eyes to deviate to the side of the lesion, and loss of ability to turn eyes to the opposite side
299
Brodmann areas 44 and 45 is what? Damage to this region would cause..?
Brocas area. Damage would cause the inability for motor production of speech.
Note: Brochas aphasia is an acquired disorder of LANGUAGE and is not the same as dysarthria (difficulty with articulation)
300
What Brodmann area controls the ability to make decisions, prioritize, plan / weigh the consequences of actions, problem solving, jusdgement, etc.
Areas 6 and 8 in the pre-fontal cortex
301
What region of the brain controls personailty and social behavior? Lesion in this region causes what?
Orbitofrontal cortex (Areas 10,11,12,24,25,32)
Personaluty changes, irritability
302
The temporal portion of the limbic system, if lesioned, can exhibit what symptoms?
Impaired decision making, distractibility, impusliveness, hyperphagia, deficient emphathy, etc
303
What brodmann areas is the postcentral gyrus. What does the postcentral gyrus do?
Areas 1,2,3. It is the somatosensory cortex.
304
If a patient tells you they can feel a painful stimulus, but cannot precisely localize it, what could this suggest about the somatosensory cortex?
That it has a lesion. The somatosensory cortex is only involved in higher aspects of painful stimuli
305
What is the brodmann region of the higher order visual area? What region is the primary visual cortex?
What is unique about Area 17 in terms of organization?
7 // 17
The retina is represented in the brain
306
Alexia and agraphia are symptoms of a person with a lesion in what brodmann area / name of region?
Area 39,40. The inferior parietal lobule
307
Brodmann area 41 is the..
Primary auditory cortex
308
Wernickes area is brodmann area\_\_\_. A lesion in the region will result in what?
22. Gibberish speech and cannot understand language
309
In a T1 weighted MRI, what color is CSF? T2?
Black, White
