Nervous System Organization Flashcards
1
Q
The brain contains approximately ______ neurons, and each neuron makes up to ____ connections with other neurons
A
86 billion, 30,000
2
Q
Groups of neurons in the central nervous system are called nuclei
A
nuclei
3
Q
Groups of axons within the central nervous system are called tracts
A
tracts
4
Q
What axis of the body does rostral-caudal refer to?
A
Nose to tail axis
5
Q
what ‘relative’ location term is rostral-caudal roughly synonymous with?
A
Anterior-posterior
6
Q
What axis of the body does dorsal-ventral refer to?
A
Back to front
7
Q
what relative location term is roughly synonymous with dorsal-ventral?
A
superior-inferior
8
Q
what do the terms medial-lateral refer to?
A
towards the middle or towards the side
9
Q
what sort of structures does ipsilateral refer to?
A
structures on the same side of the body
10
Q
what sort of structures does contralateral refer to?
A
structures on opposite sides of the body
11
Q
what sort of structures does distal refer to?
A
structures that are far apart
12
Q
the term afferent (ie: in nerve impulses) defines what sort of movement?
A
movement toward the CNS
13
Q
the term efferent (ie: nerve impulses) defines what type of movement?
A
movement away from the central nervous system
14
Q
how many names can any one part of the brain have?
A
2, functional and structural
15
Q
What is the anatomical name for the most posterior part of the frontal lobe, along the central sulcus?
A
precentral gyrus
16
Q
what is the functional name for the most posterior part of the frontal lobe, along the central sulcus?
A
primary motor cortex
17
Q
The nervous system can be divided based on its…
A
structure, or its function
18
Q
the brain and spinal cord are the 2 main components of what category?
A
CNS
19
Q
what are the two main branches of the peripheral nervous system?
A
somatic and autonomic
20
Q
the sympathetic and parasympathetic branches are subsections of which nervous system?
A
autonomic
21
Q
what type of nerves are included in the somatic nervous system?
A
cranial nerves and spinal nerves
22
Q
what are the components of the ANATOMICAL nervous system divisions?
A
CNS: brain, spinal cord
PNS: somatic and autonomic nervous systems
23
Q
what are the components of the FUNCTIONAL nervous system divisions?
A
CNS: brain, spinal cord
Somatic Nervous System: cranial nerves, spinal nerves
Autonomic Nervous System: parasympathetic division, sympathetic division
24
Q
what is the function of the CNS?
A
to mediate behaviour
25
what is the function of the somatic nervous system?
to transmit sensation and produce movement
26
what is the function of the autonomic nervous system?
to balance internal functions
27
what are all the ways that the central nervous system is protected?
-by bone (skull, vertebral column) surrounding the tissue of the CNS
28
3 types of what surround the CNS to hold it in place, and what are their names?
Meninges
3 types: Dura mater, arachnoid mater, pia mater
29
what is the dura mater?
literally, "tough mother". is the tough outer covering of the CNS
30
what is the arachnoid mater?
weblike structures that connect the inner and outer layers within the CNS
31
what is the Pia mater?
the tough inner layer that adheres to the surface of the brain
32
what substance fills the spaces in and around the meninges, and what is its function?
Cerebrospinal fluid, absorbs shocks and carries away waste
33
what structure provides chemical protection to the CNS?
Blood brain barrier
34
how is the BBB formed?
by astroglia that hold the cells of the blood vessels tightly together.
35
how does the BBB provide chemical protection to the CNS?
Regulates what molecules can exit the blood supply to enter the brain.
36
what is the benefit of having numerous arteries supply blood to the brain?
ensures that damage to a single blood vessel would not interrupt blood flow to the entire brain
37
what is a stroke?
an interruption of blood supply to the brain, either because the artery becomes blocked, or because the artery bursts
38
what does the type of deficit observed after a stroke inform clinicians about?
the location of the blood damage, and therefore provides a strong suggestion about which blood vessel is damaged
39
In utero, how does the brain start?
as neural stem cells that are undifferentiated
40
stem cells divide into ____ which develop into ____ or _____
neuroblasts ---> neurons, or glioblasts ---> glia
41
what are the three basic types of neurons?
sensory, interneurons, motor
42
what are the roles/characteristics of sensory neurons?
-transduce info from the environment
-bipolar neurons: 1 axon and 1 dendrite
-somatosensory neuron has only one projection from the soma
-AFFERENT
43
what are the roles/characteristics of Interneurons?
-connect sensory and motor neurons within the CNS
-often have extensive branching of the dendrites to gather information
44
what are the roles and characteristics of motor neurons?
-found in brainstem and spinal cord
-project to muscles to carry out movement
-EFFERENT
45
what are some types of common glial cells?
ependymal cells, astrocytes, microglial cells, oligodendroglial cells, Schwann cells
46
what are the features and functions of Ependymal cells?
small, ovoid,
secrete CSF
47
what are the features and functions of astrocytes?
star shaped, symmetrical
-nutritive and support function
48
what are the features and functions of microglial cells?
small, mesodermally derived, defensive function
49
what are the features and functions of oligodendroglial cells?
asymmetrical, forms insulating myelin around axons in brain and spinal cord
50
what are the features and functions of Schwann cells?
asymmetrical, wraps around peripheral nerves to form insulating myelin
51
what makes up gray matter?
Gray matter contains the cell bodies and capillaries that supply them with blood
52
where is gray matter typically found?
Gray matter is typically the outer part of the cortex
53
what comprises white matter, and where is it typically found?
White matter is the myelinated axons that connect with other parts of the brain
White matter is typically underneath the cortex
54
what is reticular matter, and where is it found?
Reticular matter has a netlike appearance that is a mix of gray and white matter
Reticular matter tends to be found in the brainstem
55
how does the nervous system develop?
Nervous system develops from three enlargements of the embryonic spinal cord
56
What are the three enlargements of the embryonic spinal cord, at the very beginning of brain development in utero?
Prosencephalon, mesencephalon, rhombencephalon
57
What does the prosencephalon divide into?
In mammals, this divides to form the telencephalon (the cortex and the stereotypical brain) and the diencephalon (the thalamus and hypothalamus)
58
what does the mesencephalon divide into?
This remains and becomes the midbrain
59
what does the rhombencephalon divide into?
This divides to form the metencephalon (pons and cerebellum) and the myelencephalon (medulla oblongata)
60
what comprises the telencephalon?
The cortex and the stereotypical brain
61
what comprises the diencephalon?
the thalamus and hypothalamus
62
what comprises the metencephalon?
pons and cerebellum
63
what comprises the myelencephalon?
medulla oblongata
64
what is the flowchart of the encephalons?
pro ---> tel, di
mes --> mes
rhomb -->met, mye
65
the brain develops as a hollow tube, what does the hollow tube then develop into?
the hollow tube then becomes the ventricles
66
what are the ventricles filled with?
CSF
67
Where are the lateral ventricles located? ( 1 and 2)
telencephalon
(right lateral and left lateral)
68
where is the third ventricle?
midline of brain
69
where is the fourth ventricle located?
between cerebellum and brainstem
70
where does the 'hollow tube' of the brain extend?
all 4 ventricles and down the centre of the spinal cord
71
the spinal cord is ___ matter surrounded by ___ matter
The spinal cord is gray matter surrounded by white matter
72
Nerve roots branch from the cord to carry motor commands to the body (_______) and conduct sensory information into the central nervous system (posterior root)
anterior root
posterior root
73
what is the Bell- Magendie law?
The principle that afferent neurons enter the spinal cord dorsally (from the back), whereas efferent neurons issue from the spinal cord ventrally (from the front).
74
what are the names of the four segments of the spinal cord?
cervical
thoracic
lumbar
sacral
75
what is the purpose of dermatomes?
Dermatomes describe the region of the body surface innervated by each nerve
76
describe the process of sensation and the transduction of impulses across spinal nerves
1. fibers entering the posterior root bring sensory info from sensory receptors
2. fibers leaving the anterior root carry motor info to the muscles
3. collateral branches of sensory neurons may cross to the other side and influence motor neurons there
4. white-matter fiber tracts carry info to and from the brain
77
what are spinal reflexes?
Reflexes are basic behaviors that occur without cognitive input
78
where are spinal reflexes generated?
Spinal reflexes are generated in the spinal cord based on posterior sensory input making a direct connection onto the anterior motor output pathways
79
what can more complex spinal reflexes do?
More complex reflexes can integrate information across multiple spinal cord segments
80
How many pairs of cranial nerves are there and what do they do?
Twelve pairs of nerves branch from the brain and brainstem to provide sensory and motor innervation to the head, similar to what the spinal nerves do for the body
81
what types of nerves are the cranial nerves?
Some nerves are afferent (sensory), some are efferent (motor), and some are mixed
82
how can clinicians utilize info of the 12 cranial nerves to help a patient?
diagnose issues with the nervous system
83
what are the 12 cranial nerves?
1. olfactory
2. optic
3. oculomotor
4. trochlear
5. trigeminal
6. abducens
7. facial
8. auditory vestibular
9. glossopharyngeal
10. vagus
11. spinal accessory
12. hypoglossal
84
in the sympathetic branch, where are the ganglia located?
close to the spinal cord
85
in the parasympathetic branch, where are the ganglia located?
near the target organs
86
what are the 3 distinct parts of the brainstem?
midbrain, medulla, pons
87
where is the brainstem located?
Extends from where the spinal cord enters the skull to the forebrain
88
what is the function of the cerebellum?
important for motor control and sensory integration
89
what is the function of the pons?
connects cerebellum with the rest of the brain
90
what is the function of the reticular formation in the brainstem?
Reticular formation spans the pons and medulla, and sends projects to the cortex to maintain alertness and arousal
91
what are the anterior and posterior aspects of the midbrain?
tegmentum, tectum
92
what is the tectum made up of?
superior and inferior colliculi
93
what does the superior colliculi do?
relays visual information
94
what does the inferior colliculi do?
relays auditory information
95
where are the red nucleus and substantia nigra located?
tegmentum
96
what are the nuclei in the tegmentum involved in?
Nuclei here are involved in motor control, including the substantia nigra and the red nucleus
97
what surrounds the cerebral aqueduct and why is it important?
Surrounding the cerebral aqueduct is the periaqueductal gray matter, which is important for pain responses
98
the diencephalon connects what to what?
Connects the brainstem to the brain
99
what structures are part of the diencephalon?
thalamus, hypothalamus, epithalamus
100
what is the function of the hypothalamus?
Many nuclei influence a wide range of behaviors
Produces and releases many hormones that influence the entire body
101
what is the function of the thalamus?
Almost all information destined for the cortex passes through the thalamus
Some nuclei relay sensory information to the cortex
Other nuclei relay information between cortical regions
Other nuclei relay information from the cortex to the brainstem
102
what is the epithalamus?
Nuclei found posterior to the thalamus
103
what are the main structures of the telencephalon?
neocortex, basal ganglia, limbic system
104
what are the basal ganglia important for?
Basal ganglia are important for motor control and motor learning
105
what is the limbic system important for?
Limbic system is important for spatial and emotional functions
106
what is the basal ganglia made up of?
Includes the putamen, caudate nucleus, and globus pallidus
107
where does associative learning take place?
Associative learning (stimulus–response pairing) takes place in the basal ganglia
108
how does the basal ganglia work to produce fluid, skilled motions?
Integrates sensory and motor information to produce fluid, skilled movements
109
what type of connections do the basal ganglia/cortex and basal ganglia/hindbrain have?
reciprocal connections
110
how do we know about the reciprocal connections between the basal ganglia and the other areas of the brain?
from studies of diseases of motor control
111
what type of movement is characteristic of Huntington disease?
excessive movement
112
what type of movement is characteristic of Parkinsons' disease?
loss of movement
113
what part of the brain is representative of an older part of the brain from evolutionary history?
Limbic system
114
where is the amygdala located, and what is its function?
Small nuclei in medial temporal lobes
Important in emotion and understanding emotion in others
115
where is the hippocampus located, and what is its function?
Seahorse-shaped structure in medial temporal lobes
Important in personal memories and navigation
116
where is the cingulate cortex located, and what is its function?
Arcs over the lateral ventricles
Involved in decision making and executive functions
117
what is the neocortex?
-Outer layer of the forebrain
Only 1.5–3 mm thick and includes six layers of cells
Divided into two hemispheres by the longitudinal fissure
Four lobes have different functions
118
in talking about brain structures, ridges are ___, while clefts are ____
gyri, sulci
119
describe the concept of cortical organization
Different parts of the cortex serve different functions, and the inputs to and outputs from these areas can be mapped on the surface of the brain
120
In terms of cortical organization, where do primary areas receive projections from?
Primary areas receive projections directly from sensory systems or project directly to muscles
121
in terms of cortical organization, what are secondary areas?
Secondary areas are located near primary areas and do more elaborate processing of the information, interpret inputs or organize movements
122
In terms of cortical organization, what are tertiary areas?
Tertiary areas integrate information across senses to coordinate cognitive functions and behaviors
123
how many layers are the cells in the cortex divided into?
6
124
which layer of the cortex is the outermost layer?
1
125
which layer of the cortex is the inner most layer (next to white matter)?
6
126
where does the first 1-3 layers of the cortex receive info from?
receives input from other cortical areas
127
where does the 4th layer of the cortex primarily receive input from?
sensory systems
128
what do layers 5 and 6 of the cortex do?
Layers V and VI send output to other brain areas or to the spinal cord for motor control
129
what can be said about the relationship between how thick a cortical layer is and its function?
The function of a part of the cortex can be inferred by looking at the thickness of the different cortical layers
130
how are cells organized in the neocortex?
there is a motor cortex and a sensory cortex, and each have 6 layers
131
define Brodmann's areas:
A Brodmann area is a region of the cerebral cortex, in the human or other primate brain, defined by its cytoarchitecture, or histological structure and organization of cells.
132
what do cells within a column of the cortex relate to?
Cells within a column of the cortex relate to similar functions or represent the same part of the external world
133
how do the columns of the neocortex differ from one another?
Columns differ in the types of cells they contain and the thickness of the layers
134
what are cortical connections, and where can these connections form?
Long-range connections between cortical areas enable the coordination of high-level behaviors
Connections between different lobes
Connections from one part of a lobe to another
Connections between the two hemisphere
Connections through the thalamus
135
Each hemisphere of the brain typically receives input from and sends output to the _______ side of the body
contralateral
136
describe how the 'crossed brain' concept applies to the visual system
In the visual system, the information from both eyes is combined to represent the left visual field in the right occipital lobe of the brain and the right visual field in the left occipital lobe
