Intro to Neuro Flashcards
(282 cards)
1
Q
What does the science of Neuroscience focus on?
A
The structure and function of the nervous system including:
- Molecular Biology
- Cellular Biology
- Neural Development
- Physiology
- Anatomy
- Behavioral Neuroscience
- Cognitive Neuroscience
2
Q
What is neurology?
A
A branch of medicine concerned with disorders and diseases of the nervous system
3
Q
What is the focus of molecular neuroscience?
A
- Studies the role of individual molecules in the nervous system
- Investigates the chemistry and physics involved in neural function
- Involves the study of ionic exchanges required for action potentials
4
Q
What is the focus of cellular neuroscience?
A
Studies the cells of the nervous system and how they function
5
Q
What is the focus of systems neuroscience?
A
- Studies the processes within neural circuits of the CNS
- Seeks to understand how neural circuits function to produce Sensation, Movement, Behavior, Emotion, and Memories
- Helps in the understanding of neurological, psychological and behavioral disorders
6
Q
What is the focus of behavioral neuroscience?
A
Studies the biological bases of behavior
Examines how the brain affects behavior
7
Q
What is the focus of cognitive neuroscience?
A
Studies how the brain creates and controls:
- Learning
- Problem-solving
- Thought
- Language
- Memory
8
Q
What is the overall function of the nervous system?
A
The master controlling and communicating system of the body
9
Q
How do nervous system cells communicate?
A
Electrical and chemical signals
10
Q
What are the characteristics of nervous system signals?
A
Signals are rapid, specific and usually cause an almost immediate response
11
Q
What is included in the CNS?
A
Brain
Spinal Cord
12
Q
What is the general function of the CNS?
A
Acts as the Integration and Command Center
13
Q
What is included in the PNS?
A
Consists of all neural tissue outside of the CNS, including the Cranial Nerves, Spinal Nerves, Peripheral Nerves
14
Q
What are the cranial nerves?
A
Nerves connected to the brain/brain stem
15
Q
What are the spinal nerves?
A
Nerves attached to the spinal cord
16
Q
What are the peripheral nerves?
A
Consist of bundles of axons that connect spinal nerves to peripheral structures
17
Q
What are the divisions of the PNS?
A
Sensory (Afferent) Division
Motor (Efferent) Division
18
Q
What is the general function of the Sensory (Afferent) Division?
A
Conducts impulses from receptors in the PNS to the CNS
19
Q
What are the 2 Functional Subdivisions of the Sensory (Afferent) Division of the PNS?
A
Somatic Sensory Nerve Fibers
Visceral Sensory Nerve Fibers
20
Q
What is the function of Somatic Sensory Nerve Fibers?
A
Conduct impulses from:
- Skin
- Skeletal Muscles
- Joints
21
Q
What is the function of Visceral Sensory Nerve Fibers?
A
Conduct impulses from Visceral Organs
22
Q
What is the general function of the Motor (Efferent) Division?
A
Conducts impulses from CNS to effectors in the PNS
23
Q
What are the 2 main parts of the Motor (Efferent) Division?
A
Somatic Nervous System
Autonomic Nervous System
24
Q
What is the function of the Somatic Nervous System?
A
Somatic Motor (voluntary)
Conducts impulses from the CNS to Skeletal Muscles
25
What is the function of the Autonomic Nervous System (ANS)?
Visceral Motor (involuntary)
Conducts impulses from the CNS to Cardiac Muscles, Smooth Muscles, Glands
26
What are the 2 Functional Subdivisions of the ANS?
Sympathetic Division
Parasympathetic Division
27
What is the function of the Sympathetic Division and what physiological changes does it induce?
Mobilizes body systems during activity (fight or flight)
Concerned with Elevation of metabolic rate and Increased alertness
28
What is the function of the Parasympathetic Division and what physiological changes does it induce?
"Rest and digest"
Conserves energy
Lowers the metabolic rate
promotes house keeping functions during rest
29
What are neurons?
Specialized cells that generate and transmit electrical signals
30
What are nerves?
Consist of bundles of peripheral axons with associated Blood Vessels and Connective Tissue
31
Where in the nervous system are nerves found?
Lie outside of the CNS
32
What kind of fibers do spinal nerves contain?
Contain the fibers of:
- Sensory Neurons
- Motor Neurons
33
Where are neuron cell bodies located?
A Nerve does not contain the neuron cell body
Cell Bodies are located in:
- Ganglia
- Gray Matter
- Nuclei
34
What are the cell body groups of the PNS called?
Ganglia
35
What are the cell body groups of the CNS called?
Nuclei
36
What are Neuroglia (Glial Cells) ?
Cells that support, protect and insulate neurons
37
What does a nervous system tract consist of?
Bundles of axons in the CNS
Has a common Origin and Destination
38
What kind of information do the axons of a tract carry?
Carry the same type of information (sensory or motor) in same direction
39
Where do nervous system tracts travel?
within the white matter
40
How are nervous system tracts named?
according to its Origin and Destination
41
What are nervous system tracts also know as?
Fascicle or Fasciculus
Peduncle
Capsule
Lemniscus
42
What are the 2 parts of the spinal tracts and what do they do?
- Carry information up or down the spinal cord, to or from the brain
- Ascending Tracts: Carry sensory info to the brain
- Descending Tracts: Carry motor info from the brain
43
What are the functions of tracts within the brain?
Carry information from one place to another within the brain
44
What do the differences in cellular components of neural tissue do?
Produce differences in the appearance of such tissue
45
What does white matter consist of and what causes them to be white?
Regions of CNS that primarily contain:
- Myelinated Axons
- Areas that are highly myelinated appear white due to the high lipid content of myelin
46
What does gray matter consist of?
regions of CNS that contain:
- Neuronal Cell Bodies
- Dendrites
- Unmyelinated Axons
- Axon Terminals
- Neuroglia
47
What is the appearance of the cerebral cortex?
Consists of gray matter on the surface of the brain
48
Where is cerebral white matter located?
Lies deep to the gray matter of the cerebral cortex
49
What is the function of Axons in White Matter?
Convey information among different parts of the nervous system
50
Where is information in the brain integrated?
Information is integrated in gray matter
51
Where does the spinal cord begin and end?
Begins at the foramen magnum
Ends as conus medullaris (cone-shaped structure) at L1 – L2 vertebra
52
Where is the width of the spinal cord the greatest and why?
width is greater in the cervical and lumbar regions
Due to spinal nerves that emerge to supply the upper and lower limbs
53
What are the dimensions of the adult spinal cord?
About 18" long
Maximum width .55"
54
What does the cauda equina consist of and where is it located?
The collection of spinal nerve roots from L2 to 1st coccygeal nerve inferior to the conus medullaris
55
Is the spinal cord part of the PNS or the CNS?
CNS
56
Are the spinal nerves part of the PNS or the CNS?
PNS
57
What protects the spinal cord?
Bone
Meninges: Dura Mater, Arachnoid Mater (extends to the level of S2), Pia Mater
CSF
Cushion of fat in the epidural space
58
What does the Filum Terminale consist of and where is it located?
A fine connective tissue filament closely united with the pia mater
Extends from the conus medullaris
Descends through the vertebral canal and sacral canal
59
Where does Arachnoid mater end?
S2
60
What happens to filum terminale at S2?
pierces the arachnoid mater and becomes invested with dura mater
filum terminale is now called the Coccygeal Ligament
61
What does the Coccygeal Ligament Consists of?
Fibrous Connective Tissue
Pia mater
Dura mater
62
Where does Coccygeal Ligament end?
Continues inferiorly to anchor at Coccyx 1
63
What is the function of Filum Terminale?
Provides longitudinal support to the spinal cord
64
Into what area are lumbar puncture needles injected?
subarachnoid space around lower lumbar region
65
How many segments can the spinal cord be divided into?
can be divided into 31 segments based on the origins of the spinal nerves
Each segment is identified by a letter and number
66
What does a spinal cord segment consist of?
the spinal cord area where the rootlets connect to the spinal cord
67
What is the route of an axon?
Axons traveling through the rootlets, roots and spinal nerves connect a Spinal Cord Segment with a specific part of the body
68
Example: where do C6 and C7 Dermatomes convey sensory signals to?
C6 and C7 Spinal Cord Segments
69
What are the roots of the spinal nerves?
Bundles of axons that connect each spinal nerve to a segment of the spinal cord by small bundles of axons called rootlets
70
With what is each spinal segment is associated?
a pair of Dorsal Roots and Ventral Roots
71
What are dorsal roots?
Contain axons of sensory neurons that conduct sensory impulses from the PNS into the CNS (spinal cord)
72
What is each dorsal root associated with?
Dorsal Root Ganglion
73
What are Dorsal Root Ganglion and where are they located?
An enlarged area of the dorsal root that contains cell bodies of sensory neurons
Lies between the pedicles of adjacent vertebrae
74
What are dorsal rootlets
Small bundles of axons that arise from a single dorsal root (sensory)
Enter the spinal cord
75
What are the ventral rootlets?
Small bundles of axons that arise from the spinal cord
Merge to form a single ventral root (motor)
76
What are the ventral roots?
Contain axons of motor neurons that conduct motor impulses from CNS to the periphery (skeletal muscles and glands) to control somatic and visceral effectors
77
Why are there no Ventral Root Ganglia?
Because the cell bodies of somatic motor neurons are located in the ventral gray horn of the spinal cord
78
What is the Spinal Nerve Root?
The union of the ventral and dorsal roots within the intervertebral foramen
79
How is a spinal root classified?
Since it's formed by the merging of a dorsal root (sensory) and ventral root (motor) it is classified as a mixed nerve
80
How does the Spinal Nerve Root exit the vertebral column?
via openings (intervertebral foramina) between adjacent vertebrae
81
Are all spinal cord segments are aligned with their corresponding vertebrae?
not all
82
How many pairs of spinal nerves are there?
31 Pairs
```
Cervical-8
Thoracic-12
Lumbar-5
Sacrum-5
Coccyx-1
```
83
After passing through the IVF, where does the spinal nerve go?
divides into branches:
- Dorsal Ramus
- Ventral Ramus
- Meningeal Branch
84
What does the ventral ramus divided into?
Rami Communicantes (sing. Ramus Communicans):
- Gray Rami Communicantes: All spinal nerves
- White Rami Communicates: Spinal nerves T1 – L2
85
What is the function of the spinal nerve?
carries visceral motor, somatic motor, and sensory signals to and from the spinal cord
86
What is the function of Ramus communicans?
carries visceral motor signals from the ANS to organs of the ventral body cavity
87
What is the function of the anterior and posterior rami?
carry somatic motor signals from the CNS to skeletal muscles, and sensory signals from sensory receptors in the PNS to the spinal cord
88
What is the route of sensory transmission?
1. peripheral process transmits an AP from the sensory receptors to the neuron's other axon, the central process
2. central process transmits an AP form peripheral process to the posterior horn, eventually synapsing on a neuron in the spinal cord or brainstem
89
What are spinal meninges?
Protective connective tissues that encircle the spinal cord
Continuous with cranial meninges
90
What are the 3 layer of the spinal meninges?
Dura Mater: outer layer
Arachnoid Mater: middle layer
Pia Mater: inner layer; Lies directly over the nerve tissue of the spinal cord
91
What is the general appearance of the cross-sectional anatomy of the spinal cord consist of?
Consists of areas of white matter that surround an inner region of gray matter shaped like the letter H
92
What does the gray matter of the spinal cord consist of?
Neuron Cell Bodies
Unmyelinated Axons
A few Myelinated Axons
Synapses
93
How can the gray matter of the spinal cord be subdivided?
Ventral (Anterior) Gray Horns
Lateral Gray Horns (T1 – L2)
Dorsal (Posterior) Gray Horns
Gray Commissure
94
What does the white matter of the spinal cord consist of?
mainly myelinated axons
95
What is the purpose of the anterior and posterior gray commissure of the spinal cord?
Connects gray matter of right and left sides of the spinal cord where axons cross from one side of the cord to the other
96
What is the central canal of the spinal cord?
Narrow space that contains CSF that extends the entire length of the spinal cord
97
What does the Central Canal of the spinal cord continue with superiorly?
with the 4th ventricle in the
| medulla oblongata
98
What is contained within the posterior gray horn?
Axons of somatic and autonomic sensory neurons that enter the spinal cord via dorsal roots
Cell bodies of interneurons
99
What is contained within the lateral gray horn?
Cell bodies of autonomic motor neurons:
- Cardiac Muscle
- Smooth Muscle
- Glands
100
Where are the lateral gray horns located?
Only in thoracic and lumbar regions (T1 – L2)
101
What is contained within the anterior gray horn?
Cell bodies of somatic motor neurons whose axons exit the spinal cord via ventral roots
Terminal knobs of:
- Interneurons synapsing in the Anterior Gray Horn
- Descending 1st Order Motor Neurons (UMNs)
- Axons of Preganglionic Visceral Motor Neurons (whose cell bodies are located in the Lateral Gray Horns) that exit the spinal cord via ventral roots
102
Where are the anterior and posterior white commissures located?
anterior and posterior to the gray commissures
103
What is the purpose of the anterior and posterior white commissures?
Connect white matter of right and left sides of the spinal cord where axons cross from one side of the spinal cord to the other
104
What are the 3 columns (Funiculi) called that are formed by the Anterior and Posterior Gray Horns
dividing white matter?
Dorsal (Posterior) White Columns
Ventral (Anterior) White Columns
Lateral White Columns
105
What do the tracts (Fascicle or Fasciculus) of each column (funiculi) carry?
the tracts (bundle of axons) carry the same type of information (sensory or motor) in the same direction
106
What are the grooves called that divide the spinal cord into right and left sides?
Ventral (Anterior) Median Fissure
Dorsal (Posterior) Median Sulcus
107
What do nerves consist of?
Fascicles (bundles of axons)
108
What are the protective connective tissue coverings of the Spinal Nerves, Peripheral Nerves and Cranial Nerves called?
Epineurium (outer most)
Perineurium
Endoneurium (inner most)
109
What are the 3 major parts of the brain?
cerebrum
cerebellum
brain stem
110
What are the parts of the diencephalon within the cerebrum?
Thalamus
Hypothalamus
Epithalamus
Subthalamus
111
What does the brain stem connect?
spinal cord with the cerebral region
112
What are the major divisions of the brain stem?
Midbrain (Mesencephalon)
Pons
Medulla Oblongata
113
What is the largest part of the brain?
Cerebrum
114
What divides the 2 cerebral hemispheres?
Separated by the longitudinal fissure
115
What are the 3 basic regions of each cerebral hemisphere?
Cerebral Cortex: A superficial layer of gray matter; about 2 – 4 mm thick
An internal white matter
Basal Nuclei: Islands of gray matter located deep w/in white matter
116
What does the surface of the cerebrum consist of?
Gyri: Elevated ridges (folds)
Sulci: Shallow grooves
117
What are fissures within the brain?
Deep grooves that separate large regions of the brain
118
What are the 2 fissures within the brain?
Longitudinal Fissure: Separates the cerebrum along midline into right and left halves (Right and Left Cerebral Hemispheres)
Transverse Fissure: Separates the cerebrum from the cerebellum
119
What are the 6 lobes within each hemisphere?
```
Frontal
Parietal
Temporal
Occipital
Insula
Limbic (some books do not consider this to be a lobe,
but rather a system)
```
120
What is the function of the central sulcus?
Separates the Frontal Lobe from the Parietal Lobes
| =
121
What borders the central sulcus?
Anteriorly: Precentral Gyrus
Posteriorly: Postcentral Gyrus
122
What is the function of the Parieto-occipital Sulcus?
Separates the Parietal Lobes from the Occipital Lobe
123
Which part of the Parieto-occipital Sulcus is seen on the lateral surface of the hemisphere?
Only its superior end
124
Where is the main part of the Parieto-occipital Sulcus located?
on the medial surface of each hemisphere
125
What is the function of the Lateral Sulcus?
Separates the Temporal Lobe from the Parietal and Frontal Lobes
126
What is found deep within the lateral sulcus?
the Insula which is covered by portions of the Temporal Lobe, Parietal Lobe, Frontal Lobe
127
What is the Limbic “Lobe” (System) comprised of?
an interconnected group of structures w/in a wide portion of the cerebral cortex on medial side of each cerebral hemisphere
Includes parts of the Frontal and Temporal Lobes
128
What does the Limbic “Lobe” (System) surround?
Forms a rim around the corpus callosum
129
What does the Limbic “Lobe” (System) primarily include?
Cingulate Gyrus: lies above corpus callosum
Parahippocampal Gyrus: in the medial aspect of the Temporal Lobe and surrounds the hippocampus
Olfactory Cortex
130
What is the correspondence like between a specific function and a specific region of cerebral cortex?
not precise
131
What is indicated by the boundaries between regions being indistinct?
One region may have several functions
132
What are the functions of the cerebral cortex?
- Processing of Sensory, Motor, and Memory Information
- Conscious Thought
- Reasoning
- Language
- Nonverbal Communication
- Intelligence
- Personality
133
How does each cerebral hemisphere communicate sensory and motor info with the body?
Each cerebral hemisphere receives sensory information from, and sends motor commands to, the opposite side of the body
134
What is the location of cerebral white matter?
Lies deep to the gray matter of the cerebral cortex
135
What does cerebral white matter consist of?
Consists of myelinated axons bundled into tracts that are responsible for communication within the CNS
136
What are the types of tracts within the cerebrum?
Association Tracts: Connect different regions of cerebral cortex w/in same hemisphere
Commissures: Tracts that extend between right and left cerebral hemispheres (ex: Corpus Callosum)
Projection Tracts: Connect cerebral cortex of the hemispheres with lower brain (diencephalon, cerebellum, brain stem) or spinal cord
137
What is the internal capsule of the cerebrum?
A deep subcortical structure located between diencephalon and basal nuclei
Consists of a broad band of myelinated (white matter) fibers (Projection Fibers)
138
What is the function of the internal capsule of the cerebrum?
Contains axons carrying:
- Sensory signals from the thalamus to the somatosensory cortex
- Motor signals from the motor cortex to the thalamus, brainstem and spinal cord
139
What is the appearance of the Cerebrum in a transverse section?
has a V-shape appearance
140
What is the Basal Nuclei?
A group of interconnected subcortical nuclei (gray matter) that consists of 3 nuclei deep within each cerebral hemisphere
141
What are the 3 nuclei deep order within the basal nuclei?
Caudate Nucleus-> striatum -> corpus striatum
Putamen -> lentiform nucleus and striatum -> corpus striatum
Globus Pallidus -> Lentiform Nucleus -> corpus striatum
142
What are the related nuclei in the Basal Nuclei?
Subthalamic Nucleus: located inferior to the thalamus and lateral to the hypothalamus
Substantia Nigra: located in the midbrain
143
What are the Caudate Nucleus and Putamen collectively referred to as?
the Striatum
144
What are the Putamen and Globus Pallidus collectively referred to as?
the Lentiform Nucleus
145
Where do basal nuclei receive input from?
Cerebral Cortex
Thalamus
Brainstem
146
Where do basal nuclei send messages to?
Cerebral Cortex via the Thalamus
147
What are the functions of the basal nuclei?
Facilitate movement via subconscious motor control
Inhibit antagonistic and unnecessary movements
Works with limbic system to regulate emotions
Role in modulating cognitive function
148
What is the purpose of the basal nuclei function of movement via subconscious motor control?
Controls automatic motor patterns and allows for smooth, coordinated movement of learned automatic motor patterns
Examples: Swinging of arms during walking, Writing, Riding a bike
149
What is the purpose of the basal nuclei function of Inhibiting antagonistic and unnecessary movements?
Influences areas of the brain (e.g., motor cortex)
that affect movement
Different neural circuits in the basal nuclei promote and inhibit movement
150
What are the effects of Lesions Involving the Basal Nuclei?
Motor disorders
Muscle dysfunction
Movement disorders
Cognitive impairment
151
What movement disorders are associated with Lesions Involving the Basal Nuclei?
Hypokinetic disorders that result in decreased mobility: Parkinson’s disease
Hyperkinetic disorders that result in involuntary movements: Huntington’s disease
152
What is Huntington's Disease?
An inherited neurodegenerative disease
Characterized by: Choreiform movements (Involuntary, continuous movement of the body, especially of extremities and face)
Defects in behavior and cognition
153
What is the substantia nigra of the cerebrum?
Nuclei in the midbrain linked to the Basal Nuclei that assists in skeletal muscle motor control
154
What does the limbic system consist of?
A complex system of neurons that work together and span wide areas of the brain
155
Where is the limbic system located?
The medial aspect of the cerebral hemispheres
156
What parts are included in limbic system?
Hypothalamus
Thalamus
Cerebral Cortex
Hippocampus
157
What is the function of the limbic system?
It is our emotional or affective (feelings) brain
Processes emotions and memories
Puts emotional responses to odors
158
What is the thalamus?
Paired egg-shaped masses of gray matter
One located deep in each cerebral hemisphere
159
What is the Interthalamic Adhesion (Intermediate Mass) of the thalamus?
A projection of gray matter that connects the right and left thalamic bodies
160
What are the functions of the thalamus?
- Acts as a relay station
- Receives nearly all sensory information on its way to primary sensory cortex
- Processes emotional information and some memory information
- Integrates different types of sensations (e.g., touch and visual information)
- Regulates consciousness, arousal, and attention
161
Where is the hypothalamus in relation to the thalamus?
Inferior to the thalamus
162
What are the functions of the hypothalamus?
Contains several small nuclei
Helps regulate:
- Body Temperature
- Hunger
- Water Balance
- Thirst
- Metabolic Rate
- Growth
- Function of reproductive organs
Center for emotional response
Controls release of hormones by the Anterior Pituitary
Produces Posterior Pituitary hormones
163
What is the infundibulum?
A narrow stalk that connects the hypothalamus to the Pituitary Gland
164
What is the epithalamus?
Located in the posterior aspect of the Diencephalon
Contains the Pineal Gland which secretes melatonin, a hormone that helps regulate wake/sleep cycle
165
What is the subthalamus?
Inferior to the thalamus and lateral to the hypothalamus
Anatomically, it is part of the diencephalon
Functionally, it is part of the basal nuclei
166
What is the function of the Subthalamus?
Regulation of somatic motor function
167
What is the function of the brainstem?
Contains processing centers which relays information to or from the cerebrum or cerebellum
168
What are the 3 regions of the brainstem?
Midbrain (Mesencephalon)- most superior
Pons
Medulla Oblongata- most inferior
169
What are the cerebral peduncles?
A pair of nerve fiber tracts on the ventrolateral surfaces of the midbrain
170
What kind of fibers are contained within the cerebral peduncles?
Descending efferent fibers that conduct impulses from the motor cortex to the Pons, Medulla Oblongata and Spinal Cord
Some ascending afferent fibers that conduct impulses to the thalamus
171
How is the midbrain attached to the cerebellum?
via the superior cerebellar peduncles
172
What is the cerebral aqueduct?
contained within the midbrain
A channel passing through the brainstem
Connects the 3rd and 4th ventricles (for CSF)
173
What is the corpora quadrigemina?
contained within the midbrain
Contains centers for visual and auditory processing
Coordinate movements of head, eyes and trunk in response to visual and auditory stimuli
Consists of 4 dome-like dorsal protrusions (contain sensory nuclei)
- Superior Colliculi: Visual Reflex Centers
- Inferior Colliculi: Auditory Relay Centers
174
Which cranial nerves' nuclei are within the midbrain?
CN III (Oculomotor)
CN IV (Trochlear)
175
What is contained within the pons?
Tracts
Nuclei for:
- CN V (Trigeminal)
- CN VI (Abducens)
- CN VII (Facial)
- CN VIII (Vestibulocochlear)-(also in Medulla Oblongata)
176
What does the medulla oblongata connect?
brain to spinal cord
177
What is contained within the medulla oblongata?
Major centers that regulate autonomic function
Nuclei for
- CN VIII (Vestibulocochlear)- (also in the Pons)
- CN IX (Glossopharyngeal)
- CN X (Vagus)
- CN XI (Accessory)
- CN XII (Hypoglossal)
178
Where is the cerebellum located?
Posterior to the medulla and pons
Inferior to the posterior part of the cerebrum
179
How many lobes are each of the 2 cerebellar hemispheres divided into?
3 lobes
180
What is the vermis?
The mid-line of the cerebellum
Connects the right and left hemispheres
181
What is the folia?
Parallel surface folds of gray matter (cerebellar cortex)
182
What is the transverse fissure?
Separates the cerebellum from the occipital lobes of the cerebrum
183
What is the arbor vitae?
An internal region of white matter
Visible in sagittal section
Resembles branches of a tree
184
What is the direction of all fibers entering/leaving the cerebellum?
ipsilateral (do not crossover to opposite side)
185
What are the cerebellar peduncles?
3 pairs of tracts that link the cerebellum to the brainstem
- Superior Cerebellar Peduncles
- Middle Cerebellar Peduncles
- Inferior Cerebellar Peduncles
Carry afferent and efferent fibers
186
What are the functions of the cerebellum?
- Modulates voluntary muscular activity: Sends signals to motor cortex via thalamus, to help smooth movements- essential for smooth, purposeful movement but does not initiate muscle contraction
- Regulates posture and balance
- Coordinates gait
- Controls muscle tone
- May have a role in Cognition and Language Processing
187
What could be the result of damage to the cerebellum?
Ataxia: failure of voluntary muscle control in the arms and legs
Results in lack of balance and coordination and disturbance of gait
A physical finding, not a disease
Signs and Symptoms often related to location of the lesions in cerebellum
188
Are cranial nerves part of the CNS or PNS?
Part of the PNS
189
How many cranial nerves are there?
12 pairs
190
What are the assigned name and assigned number of each cranial nerve related to?
Assigned name relates either to structures served or their function
Assigned number corresponds to the nerve’s position along longitudinal axis of the brain, from rostral to caudal
191
All cranial nerves only serve structures of the head, neck, and face except which?
Vagus Nerve (CN X)
192
What does the vagus nerve (CN X) innervate?
Visceral organs in the Thoracic Cavity and abdominopelvic Cavity
Structures in the head and neck
193
What are the functions of cerebrospinal fluid?
Cushions delicate neural structures
Supports brain
Transports Nutrients, Chemical Messengers, and Waste Products
194
What produces cerebrospinal fluid?
Produced from arterial blood (protein-poor serous plasma) by the choroid plexuses in the ventricles
195
What is the choroid plexus made up of?
Consists of capillaries with thin fenestrated endothelial cells covered by specialized ependymal cells with cilia
196
What happens to the filtrate leaving the capillaries of the choroid plexus?
enters the ependymal cells where it is modified and then released as CSF into the ventricles
197
What is the function of the cilia of the ependymal cells within the choroid plexus?
Line the ventricles and central canal
Help to keep the CSF in constant motion
198
What does the Cerebrospinal fluid bathe?
The outer surfaces of the brain as it travels through the subarachnoid space
Central Canal
199
How does cerebrospinal fluid return to the blood?
in the dural sinuses via the arachnoid villi
200
Describe the ventricles of the brain?
Hollow chambers lined with ependymal cells
Contain the choroid plexus
Filled with cerebrospinal fluid
Continuous with one another, and the central canal of the spinal cord
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Where are the lateral ventricles located?
deep within each cerebral hemisphere
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What is the septum pellucidum?
A thin vertical partition
Consists of 2 thin membranes
Separates the lateral ventricles
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What is the Interventricular Foramina (foramen of Monro)?
Consist of 2 openings
Connect the lateral ventricles with the third ventricle
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What is the third ventricle?
A narrow slit-like cavity along the midline within the diencephalon
Separates the 2 thalamic bodies and Adjacent halves of the hypothalamus
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What is the cerebral aqueduct?
A slender canal that connects third ventricle with the fourth ventricle
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Where is the fourth ventricle?
Lies between the pons and cerebellum
Inferiorly, it narrows and merges with the central canal of the spinal cord
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What are the 3 openings of the fourth ventricle that allow CSF to flow into the subarachnoid space?
Median Aperture (foramen of Magendie)
2 Lateral Apertures (foramina of Luschka)
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What are the 3 connective tissue membranes of the cranial meninges?
Dura Mater (most superficial)
Arachnoid Mater
Pia Mater (most deep)
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What is the function of the cranial meninges?
Surround and protect the brain
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What kind of connective tissue membrane is the dura mater made up of?
Tough fibrous connective tissue membrane
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What are the 2 layers of the dura mater?
Periosteal Layer (outer layer): Attaches to inner surface of the skull with no epidural space; Not present around the spinal cord
Meningeal Layer (inner layer): Covers the brain and continues inferiorly as the spinal dura mater
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The 2 layers of the dura mater are fused together except at where?
except at the Dural Venous Sinuses
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What are the Dural Venous Sinuses?
Venous channels located between the periosteal and meningeal layers of dura mater
Collect CSF and venous blood from the brain and direct it into the Internal Jugular Veins of the neck
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Describe the arachnoid mater?
Middle meningeal layer with web-like extensions (arachnoid trabeculae) that secure arachnoid mater to the underlying pia mater
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What is the subdural space?
Space between the meningeal layer of the dura mater and underlying arachnoid mater
Contains a small amount of serous fluid
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What is the Subarachnoid Space?
Space between the arachnoid mater the underlying pia mater
Contains CSF and blood vessels
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What is the Arachnoid Villi?
Small projections of arachnoid mater that protrude through the menigeal layer of dura mater into the superior sagittal sinus
CSF leaves the subarachnoid space through the arachnoid villi to enter the venous circulation
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What is the pia mater?
A thin layer of connective tissue
Adhered tightly to the brain
Anchored by the processes of astrocytes
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What are the dural folds (septa)?
In several locations the meningeal layer of the dura mater extends inward
Forms a double layer of dura mater called dural folds (septa)
Act as partitions that separate specific parts of the brain
Provide stability and support to the brain
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What are the 3 dural folds?
Falx Cerebri
Tentorium Cerebelli
Falx Cerebelli
221
How is the blood supplied to peripheral nerves?
Blood vessels pierce the epineurium of peripheral nerves
Arterioles and venules travel parallel to the fascicles of neurons
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How is the blood supplied to the anterior spinal artery?
A single artery that runs along the entire length of the anterior midline of the spinal cord
223
How is the blood supplied to the Right and Left Posterior Spinal Arteries?
A pair of arteries that run along the entire length of the posterolateral aspects of the spinal cord
224
How does arterial blood flow to the brain?
mainly via the:
- Right/Left Internal Carotid Arteries
- Right/Left Vertebral Arteries
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How does venous blood flow from the brain?
from the brain it leaves the cranium via the Internal Jugular Veins and drain the dural venous sinuses
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How are the brainstem and cerebellum supplied with blood?
Branches of the vertebral arteries
Branches of the basilar artery
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The Right/Left Vertebral Arteries Merge along the ventral surface of the medulla oblongata to form what?
the Basilar Artery
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Internal Carotid Arteries and Basilar Artery interconnect to form what?
an anastomosis called the Cerebral Arterial Circle (Circle of Willis)
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The Internal Carotid Artery terminal branches to form what?
Anterior Cerebral Arteries
Middle Cerebral Arteries
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What is the Circle of Willis (Cerebral Arterial Circle)?
A circle of communicating arteries
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The Circle of Willis (Cerebral Arterial Circle) encircles what?
Infundibulum of the pituitary gland
Optic chiasm
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What is the function of the Circle of Willis (Cerebral Arterial Circle)?
Provides collateral circulation to the brain
Unites the brain’s anterior and posterior blood supplies
Allows the brain to receive blood from 2 main arteries:
- Internal Carotid Arteries
- Vertebral Arteries
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What does the Circle of Willis (Cerebral Arterial Circle) reduce the likelihood of?
a serious interruption of circulation if one of the vessels becomes occluded
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What forms the posterior part of the Circle of Willis?
Right/Left Posterior Cerebral Arteries
Formed by the bifurcation of the Basilar Artery
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What forms the anterior part of the Circle of Willis?
Right/Left Anterior Cerebral Arteries
-One of two terminal branches of the Internal Carotid Arteries are joined by the Anterior Communicating Artery
Right/Left Posterior Communicating Arteries
- Branch off Internal Carotid Arteries just proximal to terminal branches
- Join Internal Carotid Arteries with Posterior Cerebral Arteries
- Act as an anastomosis between the anterior arterial system (Internal Carotid Arteries) and the posterior arterial system (Vertebral Arteries)
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What is a stroke (Cerebrovascular Accident)?
Interruption of blood supply to a portion of the brain
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What is the most common site of a stroke?
Middle Cerebral Artery- A branch of the Internal Carotid Artery
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What are the hemodynamic risk zones?
Watershed Areas
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What areas of the brain are included in Watershed Areas?
areas of the brain that are located distal to primary distribution areas for anterior, posterior, and middle cerebral arteries
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What is blood flow like to watershed areas?
These areas only receive marginal blood flow because they receive blood via small anastomoses that link the ends of the cerebral arteries
241
Watershed areas are the first to be deprived of blood flow in the event of what?
cerebral hypoprofusion
Example: Cerebral Watershed Infarct
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What is the primary purpose of studying the nervous system?
To understand the effects of nervous system lesions
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Define epidemiology
The study of disease occurrence in human populations
Looks for patterns of persons affected with a particular disease or disorder (Age, race, lifestyle, dietary habits, etc)
244
What does epidemiology look at?
How:
- Disease is spread
- To control disease
- To prevent disease
- To eliminate disease
245
What are the 2 Measures of Disease Frequency?
incidence: number of new cases of a disease in a given population during a specified time
prevalence: number of existing cases of a disease in a population at a given point in time
246
Define disease
A deviation from normal structure or function of any part, organ or system (or combination of these) of the body
247
How is disease characterized by?
An etiologic agent or agents
A group of signs and symptoms
Consistent anatomic alterations
A cause, pathogenesis and prognosis which may be know or unknown
248
Define syndrome
A collection of signs and symptoms that is characteristic of a specific disease state
249
What is a lesion?
An area of abnormal tissue
May be benign (not cancer) or malignant (cancer)
250
What is a neoplasm?
A new abnormal mass of tissue
Can be benign or malignant
251
What is a tumor?
An abnormal growth resulting from uncontrolled cellular proliferation
A commonly used term for neoplasm
252
What is cancer?
Another word for a malignant tumor or malignant neoplasm
253
What is malignancy?
A term for diseases in which abnormal cells divide without control and can invade nearby tissues
254
What are the 3 lesion classifications?
Focal lesion
Multifocal lesion
Diffuse lesion
255
What is a focal lesion?
A lesion limited to a single location
Example: Spinal Cord Tumor
256
What is a Multifocal Lesion?
Multiple, individual lesions are separated by normal intervening tissue
Example: A tumor that has metastasized to several locations
257
What is a Diffuse Lesion?
A lesion that is dispersed over a large area with no distinct mass
Example: Traumatic axonal injury and diffuse cerebral edema
258
What are the 2 components of a Neurological Evaluation?
History
Examination
259
What is the purpose of a Neurological Evaluation?
To determine the probable cause of the neurological problem so that appropriate care can be provided
260
What is the purpose of getting history in a Neurological Evaluation?
Used to identify the symptoms that led the person to seek care
Knowing speed of onset and expected patterns of progression for each category of pathology is critical for recognizing when a client’s signs and symptoms require referral to a medical practitioner
261
How does knowing the speed of onset and pattern of progression for a neurological disease help with a Neurological Evaluation?
Provide important clues to the cause of nervous system dysfunction
262
What does the Clinical Course of a Disease
| describe?
the evolution of a disease
263
What are the stages of a disease?
Acute Condition: Minutes to hours
Chronic Condition: Months to years
Subacute Condition: Few days
264
Describe the acute condition of a disease?
Minutes to hours
Relatively severe manifestations such as
- High Fever
- Severe Pain
Develops quickly
Runs a short course
265
Describe the Chronic condition of a disease?
Months to years
Course of the disease may be:
- Continuous: Lasting months or years
- Recurring including periods of Exacerbations (period where there's a sudden increase in the signs and symptoms or severity of a disease) and Remissions (period where there's a decrease in the signs and symptoms or severity of a disease)
266
Describe the Subacute condition of a disease?
Few days
In between acute and chronic
Not as severe as acute
Not as prolonged as chronic
267
What is the indications for acute, subacute, and chronic onset for Neurologic Conditions?
Acute Onset: Usually indicates a vascular problem
Subacute Onset: Often indicates an inflammatory process
Chronic Onset: Suggests a tumor or degenerative disease
268
What are the categories of Patterns of progression?
Stable
Improving
Worsening
Fluctuating
269
Specific tests for Neurological Examinations
| are performed to the assess function of what?
Sensory System
Motor System
Autonomic System
270
Define diagnosis
The identification a specific disease or condition
271
What is involved in the process of determining a diagnosis?
Obtaining a patient history
Performing an examination
Evaluating signs and symptoms
Performing diagnostic tests such as
- Laboratory Tests
- Radiographic Studies
- CT Scan
- MRI
272
What is the function of the primary motor cortex?
voluntary control of skeletal muscles
273
What is the function of the primary sensory cortex?
conscious perception of touch, pressure, pain, vibration, taste, and temperature
274
What is the function of the visual cortex?
conscious perception of visual stimuli
275
What is the function of the auditory cortex?
conscious perception of auditory (hearing) stimuli
276
What is the function of the olfactory cortex?
conscious perception of olfactory (smell) stimuli
277
What is the function of the association areas?
integration and processing of sensory data; processing and initiation of motor activities
278
What is the function of the thalamus?
relay and processing centers for sensory information
279
What is the function of the hypothalamus?
centers controlling emotions, autonomic functions, and hormone production
280
What is the function of the midbrain?
processes visual and auditory data
generates reflexive somatic motor responses
maintenance of conciousness
281
What is the function of the pons?
relays sensory info to cerebellum and thalamus
subconscious somatic and visceral motor centers
282
What is the function of the medulla oblongata?
relays sensory info to thalamus and other portions of the brain stem
autonomic centers for regulation of visceral function (cardiovascular, respiratory, and digestive system activities)
