Week 3 Neural Pathways and Integration Flashcards
1
Q
Ganglion
A
Cluster of neuron cell bodies within the PNS
2
Q
Center
A
Group of CNS neuron cell bodies with a common function
3
Q
Nucleus
A
Center that displays discrete anatomic boundaries
4
Q
Nerve
A
Axon bundle extending through the PNS
5
Q
Nerve plexus
A
Network of nerves
6
Q
Tract
A
CNS axon bundle in which the axons have a similar function and share a common origin and destination
7
Q
Funiculus
A
Group of tracts in a specific area of the spinal cord
8
Q
Pathway
A
Centers and tracts that connect the CNS with body organs and systems
9
Q
3 Types of Tracts
A
- Association Tracts
- Commissural Tracts
- Projection Tracts
10
Q
Association Tracts
A
Connect different regions of cerebral cortex within the same hemisphere
11
Q
Commissural Tracts
A
Between cerebral hemispheres
Ex. corpus collosum
12
Q
Projection Tracts
A
Link cerebral cortex to the caudal brain regions
Ex. corticospinal tract from cerebrum to brainstem to spinal cord
13
Q
2 Types of Association Tracts
A
- Arcuate fibers
2. Longitudinal fasciculi
14
Q
Arcuate Fibers
A
Type of Association Tract
*Connect neighboring gyri within a single cerebral lobe
15
Q
Longitudinal Fasciculi
A
Type of Association Tract
*Connect gyri between different cerebral lobes of the same hemisphere
16
Q
Decussation in pyramids occurs where
A
In medulla oblongata
17
Q
Sensory spinal tracts
A
Exact opposite from brain, in brain grey matter is on outside, in spinal cord grey matter is on inside
18
Q
CNS communicates with body structures via
A
Pathways
19
Q
Pathways
A
How CNS communicates with body structures
-sensory or motor info
-processing and integration occur continuously
Pathways travel through the white matter of spinal cord
Connect various CNS regions with peripheral nerves
20
Q
Nervous system pathways consist of
A
A tract and a nucleus
Each tract may work with multiple nuclei groups in the CNS
21
Q
Nucleus
A
A collection of neuron cell bodies located within the CNS
22
Q
Ascending Pathways
A
Carry sensory information from the peripheral body to the brain
23
Q
Descending Pathways
A
Transmit motor information from the brain or brainstem to muscles or glands
24
Q
Decussation
A
Pathways typically cross over from one side of the body to the other at some point
*The left side of the brain processes information from the right side of the body and vice versa
25
Cajal theory about decussation
From aquatic brain to higher vertebrate. Reflex response, when fish see predator you move away. In vertebrate is on opposite side
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Somatotopy
Pathways that connect these parts of the cortex to a specific body part exhibit this
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Nervous system pathways
Most exhibit a precise correspondence between a specific area of the body and a specific area of the CNS
A pathway on L side of CNS has a matching tract on the R side of the CNS
Both L and R tracts are needed to innervate both L and R sides of body
Pathways are composed of a series of two or three neurons that work together
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Areas that are highly controlled
Hands, face, tongue
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All Nervous systems pathways are composed of
Paired tracts
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Sensory Pathways
Have primary neurons, secondary neurons and sometimes tertiary neurons that facilitate the pathway's functioning
Conduct information about limb position and the sensations of touch, temperature, pressure and pain
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Motor Pathways
Use upper motor neurons and a lower motor neuron
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Sensory Input
Sensory receptors detect stimuli and then conduct nerve impulses to the CNS
Sensory pathway centers within either the spinal cord or brainstem process and filter the incoming sensory information
99% of incoming impulses do not reach the cerebral cortex and our conscious awareness
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Incoming impulses
99% of incoming impulses do not reach the cerebral cortex and our conscious awareness
A lot of what goes on in brainstem is filtration
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Type of information sensory pathways conduct
Limb position and the sensations of touch, temperature, pressure and pain
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Type of info received from somatosensory pathways
Recptors within the skin, muscles and joints.
| -mainly stretching sensation
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Somatosensory Pathways
Process stimuli received from receptors within the skin, muscles and joints
*mainly stretching sensation
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Viscerosensory pathways
Process stimuli received from the viscera
| Ex. nausea, scratchy throat. Not as precisely located as others
38
Primary (First-Order) Neuron
Sensory pathways utilize a series of two or three neurons to transmit stimulus info from the body periphery to the brain
The first neuron is the primary (first-order) neuron
The dendrites are part of the receptor that detects a specific stimulus
Cell bodies reside in the posterior root ganglia of spinal nerves or the sensory ganglia of cranial nerves
39
Dendrites are part of
The receptor that detects a specific stimulus
40
Cell bodies reside
In the posterior root ganglia of spinal nerves or the sensory ganglia of cranial nerves
41
Secondary (Second-Order) Neuron
The axon of the primary neuron projects to a secondary neuron within the CNS.
Is an interneuron
The cell body resides within either the posterior horn of the spinal cord or a brainstem nucleus
The axon projects to the thalamus, where it synapses with the tertiary neuron
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Interneuron
The secondary neuron
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The cell body of the secondary neuron resides within
either the posterior horn of the spinal cord or a brainstem nucleus
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The axon of the secondary neuron axon projects to the
Thalamus, where it synapses with the tertiary neuron
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Diencephalon
Thalamus - Sensory impulses form all conscious senses EXCEPT olfaction converge on the thalamus
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Thalamus
Sensory impulses form all conscious senses except olfaction converge on the thalamus
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Ventral Posterior Nuclei
Relay sensory information to primary somatosensory cortex of parietal lobe
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5 Parts of Thalamus
1. Meidal group - consciousness, emotion
2. Lateral group - mood
3. Posterior group - special sense
4. Anterior group - mood
5. Ventral group - somatomotor, somatosensory
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Thalamus Medial group
Consciousness and emotion
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Thalamus Lateral group
Mood
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Thalamus Posterior group
Special sense
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Thalamus Anterior group
Mood
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Thalamus Ventral group
Somatomotor and somatosensory
54
Sensory information from CN V, CN VII, CN IX and CN X are also
Integrated in the ventroposterolateral nuclei via the trigeminothalamic tract
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Tertiary (Third-Order) Neuron
Also an interneuron
Its cell body resides within the thalamus
The thalamus is the central processing center for almost all sensory information
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3 Sensory tracts in the spinal cord
1. Posterior funiculus
2. Spinocerebellar pathway
3. Anterolateral pathway
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Fasciculus Cuneatus Pathway
Posterior Funiculus-Medial Lemniscal Pathway
| *Posterior Funiculus
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Fasciculus Gracilis Pathway
Posterior Funiculus-Medial Lemniscal Pathway
| *Posterior Funiculus
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Anterior spinothalamic Pathway
Anterolateral Pathway
| *Anterior Funiculus
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Lateral spinothalamic Pathway
Anterolateral Pathway
| *Lateral Funiculus
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Anterior spinocerebellar Pathway
Spinocerebellar Pathway
| *Lateral
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Posterior spinocerebellar Pathway
Spinocerebellar Pathway
| *Lateral Funiculus
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Function Fasciculus Cuteatus
(Posterior Funiculus)
Conduct sensory impulses for proprioceptive info about limb position and discriminative touch, precise pressure and vibration sensation
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Function Fasciculus Gracilis
(Posterior Funiculus)
Conduct sensory impulses for proprioceptive info about limb position and discriminative touch, precise pressure and vibration sensation
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Function Anterior spinothalamic
(Anterior Funiculus)
| Conducts sensory impulses for crude touch and pressure
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Function Lateral spinothalamic
(Lateral Funiculus)
| Conducts sensory impulses for pain and temperature
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Function Anterior spinocerebellar
(Lateral Funiculus)
| Conducts proprioceptive impulses from inferior regions of trunk and lower limbs
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Function Posterior spinocerebellar
(Lateral Funiculus)
| Conducts proprioceptive impulses from lower limbs, region of trunk and upper limbs.
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Is there tertiary for spinocerebellar?
No tertiary
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Posterior Funiculus-Medial Lemniscal Pathway
Projects through the spinal cord, brainstem and diencephalon before terminationg within the cerebral cortex.
71
Tracts within the spinal cord
Posterior funiculus
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Tracts within the brainstem
Medial lemniscus
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Anterolateral Pathway
Located in the anterior and lateral funiculi of the spinal cord
Axons projecting from primary neurons enter the spinal cord and synapse on secondary neurons within the posterior horns
74
Spinocerebellar Pathway
Regulation of posture, not under conscious control
Anterior and posterior tracts
They do NOT use tertiary neurons
75
Sensory Pathways
Have primary neurons, secondary neurons and sometimes tertiary neurons that facilitate the pathway's functioning
76
Motor Pathways
Use upper motor neurons and a lower motor neuron
77
Motor Pathways Descending pathways
in the brain and spinal cord that control activities of skeletal muscle
78
Motor Pathways formed from
The cerebral nuclei, the cerebellum, descending projection tracts and motor neurons
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Motor Pathways regulate
The activities of skeletal muscle
| Active control
80
Function Lateral corticospinal tracts
Voluntary movement of limb muscles
81
Function Anterior corticospinal tracts
Voluntary movement of axial muscles
| Trunk
82
Corticobulbar Tracts
Originate from the facial region of the motor homunculus within the primary motor cortex
Axons extend to the brainstem, where they synapse with lower motor neuron cell bodies that are housed within brainstem cranial nerve nuclei.
Axons of these lower motor neurons help form the cranial nerves.
83
Corticospinal Tracts
Descend through the cerebral cortex through the brainstem and form a thick bulges in the medulla called the pyramids
84
Pyramids
Descend from the cerebral cortex through the brainstem and form a pair of thick bulges in the medulla
85
Corticospinal Tracts
Continue into the spinal cord to synapse on lower motor neurons in the anterior horn of the spinal cord
86
Indirect Pathway
Several nuclei within the mesencephalon initiate motor commands for activities that occur at an unconscious level
Cell bodies of its upper motor neurons are located within brainstem nuclei
Acons take a complex, circuitous route before finally conducting the motor impulse into the spinal cord
87
Indirect motor pathways in the spinal cord
Originate from neurons housed within the brainstem
Muscular activity localized within the head, limbs and trunk of the body
Multisynatic
Exhibit a high degree of complexity
88
Rubrospinal tract function
Regulates and controls precise, discrete movements and tone in flexor muscles of the limbs
89
Reticulospinal tract function
Controls more unskilled automatic movements related to posture and maintaining balance
90
Tectospinal tract function
Regulates positional changes of the arms, eyes, head and neck due to visual and auditory stimuli
91
Vestibulospinal tract function
Regulates muscular activity that helps maintain balance during sitting, standing and walking
92
Lateral corticospinal tract function
Voluntary limb muscles
93
Rubrospinal tract function
Discrete movement: flexors of limbs
94
Anterior corticospinal tract
Voluntary axial muscles
95
Reticulospinal tract
Posture
96
Vestibulospinal tract
Balance during movement
97
Tectospinal tract
Visual and auditory integration with movement
98
Voluntary: limb muscles
Lateral corticospinal tract
99
Discrete movement: flexors of limbs
Rubrospinal tract
100
Voluntary: axial muscles (trunk)
Anterior corticospinal tract
101
Posture
Reticulospinal tract
102
Balance during movement
Vestibulospinal tract
103
Visual and auditory integration with movement
Tectospinal tract
104
Tectum
Visual and auditory relay
105
Tegmentum
Posture
106
Reticular formation
discrete movement
107
Red nucleus
Discrete movement
108
Substantia Nigra
Inhibit skeletal muscles
