Mansour Study guide for exam 1 Flashcards
(107 cards)
1
Q
How many brain regions are there?
A
There are 5 embryonically derived brain regions
- Telencephalon
- Diencephalon-3 parts
- Mesencephalon
- Metencephalon
- Myelencephalon
2
Q
List at least 2 features/structures in each of the following brain
regions
A
3
Q
The lateral ventricle is part of
A
Telencephalon
4
Q
Mesencephalon: Structures/Function
A
Tectum
Coropa quadrigemina
- Rostral Colliculi (visual Reflexes)
- Caudal Colliculi (auditory Reflexes)
Mesencephalic Aqueduct
Tegmentum:
- Reticular activating system (RAS)
- red nuclei (UMN
CN III( Oculomotor) and IV (Trochlear)
Crus Cerebri
Cerebral Peduncles
- tegmentum
- substantia nigra
-crus cerebri
5
Q
What happens when there is a lesion in the midbrain
A
May cause loss of consciousness
6
Q
Ascending Reticular Activating system (ARAS)
A
The Ascending Reticular Activating System (ARAS), or reticular formation, is a network of anatomically and physiologically distinct nuclei in the brainstem that function to “activate” the cerebral cortex and maintain consciousness
7
Q
Corpus Callosum
A
Is an example of commissural fibers L and R cerebral Hemispheres.
Association fibers or cortex within same cerebral hemisphere.
8
Q
Visual input is linked to motor output by
A
Rostral Colliculus
and Lateral geniculate
9
Q
Lateral geniculate is part______ of the brain
A
Diencephalon
10
Q
Primary motor cortex Lobe
A
Frontal
11
Q
Motor and sensory lobe
A
Parietal
12
Q
Primary visual lobe
A
Occipital
13
Q
Primary auditory lobe
A
Temporal
14
Q
Cranial Nerves emerging from the 5 major regions
A
Telencephalon CN I
* Diencephalon CN II
* Mesencephalon CN III CN IV
* Metencephalon CN V
* Myelencephalon CN VI-XII
15
Q
Of the following cranial nerve which
arises from diencephalon?
A
CN II Optic Nerve
16
Q
What septum separating cerebral hemispheres
A
Longitudinal Fissure
17
Q
The_______separates the cerebrum from cerebellum
A
Transverse Fissure
18
Q
Types of Neuroglia
A
Ependymal Cells
- Neuro-epithelial producing CSF
Oligodendrocytes
- Myelination in CNS
Satellite cells
COME BACK
Astrocytes
- BBB waste/ repair in CNS
Microglia
- Macrophage in CNS
Schwann cells
- Myelination in PNS
19
Q
Astrocytes
A
Astrocytes project foot processes that envelop the basement membrane of capillaries (BBB), neurons (bodies-perikaryons or soma), and synapses
20
Q
Where do Astrocytes work
A
Blood vessels
Other Astrocytes
Synapses
Neuron Cell Bodies
21
Q
Facts about glial cells
A
neuroglia or glial cells are defined as supportive
cells
non-excitable
Fibrous astrocytes are found mainly in the white
matter
Protoplasmic astrocytes are found mainly in the
gray matter
Astrocytes project foot processes that envelop the basement membrane of capillaries, neurons, and synapses
22
Q
Spinal Cord CHECK THIS
A
Gray matter-cell bodies of LMN (dorsal, lateral and ventral horns)
White matter-axons (descending & ascending UMN neurons)
Ventral horn–> Somatic LMN
Dorsal horn–> Sensory Fibers
Lateral Horn–> Autonomic
23
Q
Spinal Cord location of LMN
A
Ventral gray matter: motor role, LMN
Dorsal gray matter: sensory role
24
Q
Dorsal roots are formed by what processes
A
Dorsal roots are formed by processes of the dorsal root ganglia
25
The white matter of the spinal cord contains all the following except:
Schwann Cells, they are in the peripheral nervous system
26
A large lesion of the ventral horn likely induces
Muscle atrophy
27
Spinal Cord regions
Neck ( C1-5)
Thoracic Limb (C6-T2)
Thoracolumbar Region ( T3-L3)
Pelvic Limb (L4- S1)
Pelvis (S1-S3)
28
Meninges
Dura Mater
Arachnoid membrane
Pia Mater
29
Leptomeninges
Arachnoid and Pia mater
30
Arachnoid membrane
Fluid-filled subarachnoid space that contains cerebrospinal fluid (CSF)
31
CSF Pathway
Lateral ventricles through interventricular foramen
Third Ventricle
Cerebral aqueduct
Fourth Ventricle
32
What does the cerebral aqueduct connect
The third ventricle with the fourth ventricle
33
The major regulators of CSF pressure
Arachnoid Villus
(CSF from subarachnoid space passes into the venous circulation)
34
What Produces CSF
Choroid plexus
35
What is the Epidural space filled with
Fat
36
The Cerebrospinal fluid circulates in which of the following spaces
Subarachnoid Space
37
Lacking in circumventricular organs (CVO)
Median eminence
Area postrema
Pineal Gland
Subfornical Organ
38
3 Key nerves in Micturition
Hypogastric nerve
Pelvic Nerve
Pudendal nerve
39
The types of fibers in each of the nerves in micturition
Sympathetic : Hypogastric
Parasympathetic: Pelvic
Somatic Motor: Pudendal
40
Neurogenic Causes
Trauma ( UMN vs LMN)
41
Neurogenic
(Cerebrum/brain stem
[pons] or spinal cord)
42
Nonneurogenic
* Anatomic
* Diseases-UTI
* Drugs
* Aging
* Spaying
43
CNS Centers for Micturition
Brainstem/Pons: Micturition center (Integration)
Cerebrum: Voluntary Control
Cerebellum: Inhibitory influence on micturition
44
Bladder Filling
Sensory input( pelvic, hypogastric, pudendal)
- pelvic is the major source
Increased sphincter tone ( pudendal, hypogastric)
- makes it tight
Detrusor relaxation (hypogastric)
Decrease parasympathetic tone (pelvic)
Input from higher centers--> voluntary control, integration of sensory input
45
Bladder Emptying
- Sensory input (pelvic, hypogastric, pudendal)
- Integration by higher centers
- Decreased sympathetic/ somatic tone (hypogastric pudendal)
- Decreased sphincter tone (hypogastric, pudendal), Sphincter relaxation
- Detrusor contraction (pelvic)
46
Summary Of Micturition
Micturition depends on the coordinated action between the sympathetic, parasympathetic, somatic nervous systems and central control centers (pontine and cerebrum).
The somatic (pudendal n) and sympathetic (hypogastric n) divisions promote storage (s and s) while the parasympathetic division (pelvic n) promotes voiding (p for peeing)
47
Myasthenia Gravis
(deficiency in AChR)
48
Tick Paralysis
Interferes with Ca preventing release of
Ach at NMJ
49
Botulism
Clostridium botulinum toxin (type c) Cleaves SNARE proteins. This leads to Inhibition of Ca binding to pre-synaptic vesicles and inhibition of the release of Ach into NMJ
50
Typical symptoms seen with LMN dysfunction
Noodle-decreased or absent reflexes-atrophy (fast)
51
Typical symptoms seen with UMN dysfunction
Stick-Normal or exaggerated reflexes—atrophy (slow)
52
Clinical signs of LMN disease
* LMN= Weakness/inability to support weight (paresis/paralysis (pleg* Short strides (decrease stride length// choppy gait
* Postural reaction normal (with appropriate support)
* Hyporeflexia
* Decreased muscle tone
* Muscle atrophy
53
Signs of LMN damage
If LMNs cause muscle to contract, then…
- When LMNs are damaged, the muscles they innervate don’t contract
Tests/Indicators of muscle contractility
* Muscle strength
* Muscle size
* Muscle tone
* Ability to produce reflex response
54
Functions of the motor system (UMN & LMN)
* Voluntary control of muscles (our interest in skeletal muscles)
* Enables animals to walk, run, eat, bite and perform complex movement
55
Terms describing clinical conditions
Monoparesis (sensory), monoplegia (motor)
Paraparesis (sensory) , paraplegia (motor)
Hemiparesis (sensory), hemiplegia (motor)
Tetraparesis (sensory) , tetraplegia (motor)
56
Monoparesis, monoplegia
1 limb affected (fore or hind)
57
Paraparesis, paraplegia
Both pelvic limbs affected (lower
limbs)
58
Hemiparesis, hemiplegia
Both limbs on same side affected
59
Tetraparesis, tetraplegia
All 4 limbs affected
60
LMN components
Innervate skeletal muscles-alpha (α fibers)
(involves 36 pair spinal nerves and 9 pairs of CNN (III, IV, V, VI, VII, IX, X, XI, XII)
61
UMN Components
(Descending tracts) in cerebral cortex and
brainstem. They influence LMN
62
Know clinical signs of CN V
Dropped jaw, atrophy of muscle of mastication
63
Know clinical signs of CN VII
Inability to move lid (blinking), ear, lips, dry eye
64
Know clinical signs of CN X
Dysphagia, megaesophagus, dysphonia
65
Know clinical signs of CN XII
Tongue paralysis—leads to dysphagia
66
Know clinical signs of CN III, IV, VI
Strabismus, pupil (CN III)
67
What do LMNs in the brainstem and spinal cord regulate
Lowest level of motor hierarchy
Skeletal muscle
including axial muscles for posture
Cerebral Motor cortex--> basal nuclei--> Brain stem ( UMN)--> Spinal cord (LMN)
68
Cell body for LMN locations
Midbrain: III & IV
Pons: V
Medulla: VI,VII, IX, X, (XI), XII
Ventral Horn gray from C1 through CD5: all spinal nerves
- Also, intermediate gray from T1-L4, S1-S3)
69
What does the UMN do/ Function
* ‘Tells’ the LMN what to do * Stimulate or inhibit the LMN
* Initiation of voluntary movement
* Maintenance of muscle tone and support against gravity
* Regulation of posture
70
Cell bodies for UMN location
* UMN- Cell bodies are located in
the cerebrum and brainstem
(midbrain-pons-Medulla)
* Entire UMN is confined to CNS
71
How does UMN work
Upper Motor Neuron axons
- Some go to cranial motor nuclei (LMNs)
- Most go to spinal cord lateral/ventral horn (LMNs)
- Project long distances
Most synapse on INTERNEURONS
- Inhibitory interneurons
- Excitatory interneurons
72
Cerebral motor cortex motor tracts
3 descending motor tracts from the cerebral cortex:
* Corticopontine tract
* Corticonuclear tract
(CNN LMN nuclei)
* Corticospinal tract
(Lateral & ventral)
(LMN-limbs)
73
Basal Ganglia : Part of the cerebrum
The “basal nuclei” refers to a group of subcortical nuclei responsible primarily for motor control, as well as other roles such as motor learning, executive functions and behaviors, and emotions.
74
Basal Nuclei
Caudate, putamen-globus pallidus
Makes movement successful
(regulate movement vigor)
75
Descending spinal motor tracts (from cerebral cortex/brainstem)
Lateral funiculus tracts stimulates flexion and inhibits extension
Ventral funiculus tract stimulate extension and inhibits flexion
76
Lateral funiculus tracts
Lateral funiculus tracts stimulates flexion and inhibits extension
- Lateral corticospinal (cerebral cortex)
- Rubrospinal (red nucleus)
- Medullary reticulospinal (medullary Reticular Formation)
77
Ventral funiculus tracts
Ventral funiculus tract stimulate extension and inhibits flexion
- Pontine reticulospinal ( Pontine Reticular Formation)
- Tectospinal ( Rostral Colliculus)
- Lateral vestibulospinal ( Vestibular nuclei)
-Medial vestibulospinal ( Vestibular nuclei)
78
LMN clinical relevance of gait, reflex, muscle tone
Gait: paresis – paralysis
Reflexes: decreased to absent
Muscle tone: decreased to absent
Atrophy: rapid, severe
79
UMN clinical relevance of gait, reflex, muscle tone
Gait: ataxia, paresis – paralysis
Reflexes: Normal – exaggerated
Muscle tone: normal – exaggerated
Atrophy: slow, moderate
80
What Brainstem Motor Control is hypotonia
LMN: Hypotonia
flabby-baby bean doll
81
What Brainstem Motor Control is hypertonia
UMN: Hypertonia
Rigid
82
Spinal cord reflexes
Used clinically to assess neurological
patients
83
Reflex arc:
1. Receptor
2. Afferent pathway
3. Integrating center
4. Efferent pathway : LMN
5. Effector (visible response)
84
Neurologic exam form
Spinal cord reflexes:
Biceps
- Peripheral Nerve: Musculocutaneous
- Spinal Cord Segment: c6-c8
- Vertebral Level:c5-c7
Triceps
- Peripheral Nerve:Radial
- Spinal Cord Segment:C7-T2
- Vertebral Level: c6-T1
Extensor Carpi Radialis
- Peripheral Nerve:Radial
- Spinal Cord Segment: C7-T2
- Vertebral Level: C6-T1
Thoracic limb flexor withdrawal
- Peripheral Nerve:Musculocutaneous, median, ulnar
- Spinal Cord Segment:C6-T2
- Vertebral Level: C5-T1
Patellar
- Peripheral Nerve: Femoral
- Spinal Cord Segment: L4-L6
- Vertebral Level:L3-L4
Cranial Tibial
- Peripheral Nerve: Peroneal
- Spinal Cord Segment: L6-L7
- Vertebral Level:L4
Gastrocnemius
- Peripheral Nerve: Tibial
- Spinal Cord Segment: L7-S1
- Vertebral Level:
Pelvic Limb Flexor Withdrawal
- Peripheral Nerve: Sciatic ( Femoral if include flexion of hip)
- Spinal Cord Segment: L6-S1
- Vertebral Level: L4-L5
** Perineal Reflex
- Peripheral Nerve:Pudendal
- Spinal Cord Segment: S1-S2 (S3)
- Vertebral Level: L5
85
Perineal Reflex
- Peripheral Nerve:Pudendal
- Spinal Cord Segment: S1-S2 (S3)
- Vertebral Level: L5
86
What happens if any part of the reflex pathway is damaged
If any part of the reflex pathway is damaged, you will see a decreased or absent reflex response
- LMN signs
87
Muscle Spindles
* Found within skeletal muscles
* Detect muscle : Stretch (rate and degree)
* Important for maintaining muscle tone
and posture (antigravity muscles/extensors)
* Role in myotatic reflexes
88
Difference between spindle afferents
Muscle spindle afferents transduce muscle length (STRETCH) , whereas GTO afferents transduce muscle force.
89
What are alpha motor neurons
Innervate extrafusal fibers, the highly
contracting fibers that supply the muscle with its power.
90
What are Gamma motor neurons
innervate intrafusal fibers, which contract only slightly. ... This contraction keeps the spindle taut at all times and maintains its sensitivity to changes in the length of the muscle.
91
Spinal cord reflexes: Crossed Extensor Reflex
In a normal standing animal, when a noxious
stimulus is applied to a limb, the opposite limb
will extend (normal crossed extensor reflex)
when the other limb is pulled away from the
stimulus.
In a recumbent animal, when a noxious
stimulus is applied to a limb, the opposite limb
should NOT extend (inhibited by UMNs) when
the stimulated limb is pulled away from the
stimulus.
The presence of a crossed extensor reflex in a
recumbent animal is considered abnormal and
a sign of:UMN disease (loss of input from
higher brain centers).
The crossed extensor reflex is evaluated while
performing the flexor withdrawal reflex,
however, they are separate reflexes.
92
Spinal cord reflexes: Cutaneous trunci reflex
Sensory stimulus to the skin along the back results in twitching of the skin via activation of the cutaneous trunci muscle by the: Lateral thoracic artery
* Used clinically to assist in the location of spinal cord lesions from: C8-T1 through T2-L7.
Cutaneous trunci muscle is supplied
by the lateral thoracic nerve (arises
from C8-T1 spinal cord
segments)
93
Panniculus Reflex
Intersegmental reflex
94
What happens to the Cutaneous Trunci reflex with a spinal cord injury
With spinal cord injury, the cutaneous trunci reflex may be absent behind the site of the injury pending the severity of the injury
* Interruption of the sensory component of the reflex arc
95
What happens to the Cutaneous Trunci reflex with a brachial plexus avulsion
With brachial plexus avulsion, the cutaneous trunci reflex may be absent on the affected side (C8-T1 nerve roots for lateral thoracic nerve)
Interruption of the: Efferent component of the reflex arc
96
Avulsion of Brachial plexus
Findings: Both dorsal & ventral roots are
affected. No cutaneous trunci reflex on left side
Deficits: Ipsilateral (motor and sensory)
LMN-TL, LTN.
Sensory deficit-Dorsal horn affected
97
Lesion at Ventral horn at C6-T1
Findings: No ipsilateral cutaneous trunci reflex (left)
Deficit: LMN-TL, LTN
No sensory deficit (dorsal root intact)
98
Large Bilateral Lesion
Cutaneous trunci reflex absent caudal to lesion
UMN-PL
99
Left Lateral Funiculus
Affect left (ipsilateral) cutaneous trunci reflex
UMN Left PL
100
Lesion Localization
101
Lesion affecting C1-C5
N or UMN thoracic limb, pelvic limb, organ sphincters
* All limbs affected
* Tetra-paresis/plegia
* UMN signs to limbs/sphincters
* Normal cutaneous trunci? Yes or No
* Normal mentation and CNN
102
Lesion affecting T3-L3:
N or UMN pelvic limb, pelvic organ sphincters
* Only PLs affected
* Para-paresis/plegia
* UMN signs to PL/sphincters
* Normal TL
* Cutaneous trunci? Absent behind the legion
* Normal mentation and CNN
103
Lesion affecting L4-S1(2)
LMN pelvic limb N or UMN pelvic organ sphincters
* Only PLs affected
* Para-paresis/plegia
* LMN signs to PL
* UMN sphincters
* Normal TL
* Cutaneous trunci reflex? Yes or No
* Normal mentation and CNN
104
Lesion affecting C6-T2
LMN thoracic limb N or UMN pelvic limb, organ sphincters
* All limbs affected
* Tetra-paresis/plegia
* LMN to TL & UMN signs to PL/sphincters
* Cutaneous trunci?: Absent
* Horner syndrome +/-
* Normal mentation and CNN
105
Lesion affecting S1-S3
LMN pelvic
organ sphincters
106
Paresis
Some voluntary movement
107
Plegic
No voluntary motor movement (paralysis)
