PSYC*2410 Chapter 3: Anatomy of the Nervous System Flashcards
(218 cards)
1
Q
What are the two divisions of the vertebrate nervous system?
A
- The central nervous system
- The peripheral nervous system
2
Q
What is the central nervous system?
A
The portion of the nervous system located within the skull and spine (brain and spinal cord)
3
Q
What is the peripheral nervous system?
A
The potion of the nervous system located outside the skull and spine
4
Q
Which division of the PNS interacts with the external environment?
A
The somatic nervous system
5
Q
Which division of the PNS that regulates the body’s internal environment?
A
The autonomic nervous system
6
Q
The efferent nerves of the autonomic nervous system are further divided into what two systems?
A
- The sympathetic nervous system
- The parasympathetic nervous system
7
Q
Which division of the nervous system stimulates, organizes, and mobilizes energy resources in threatening situations?
A
The sympathetic division
8
Q
Which division of the nervous system acts to conserve energy?
A
The parasympathetic division
9
Q
What does the relative activity of the opposing sympathetic and parasympathetic input control?
A
Each autonomic target organ
10
Q
What are afferent nerves?
A
Nerves that carry sensory signals to the CNS
11
Q
What are efferent nerves?
A
Nerves that carry signals from the CNS to the skeletal muscles (somatic NS) or internal organs (autonomic NS)
12
Q
Which type of autonomic motor nerves project from the CNS in the lumbar and thoracic regions of the spinal cord?
A
Sympathetic nerves
13
Q
Which type of autonomic motor nerves project from the brain to the sacral region of the spinal cord?
A
Parasympathetic nerves
14
Q
When sympathetic neurons synapse on second-stage neurons, are they near or far from their target organs?
A
Far
15
Q
When parasympathetic neurons synapse on second-stage neurons, are they near or far from their target organs?
A
Near
16
Q
What are cranial nerves?
A
The nerves projecting from the brain
17
Q
How many cranial nerves are there?
A
12 pairs (24 total)
18
Q
What are the first two cranial nerves?
A
- Olfactory nerves
- Optic nerve
19
Q
What are the longest cranial nerves?
A
The vagus nerves
20
Q
Where do the vagus nerves travel?
A
To and from the gut
21
Q
Are the autonomic motor fibres of cranial nerves sympathetic or parasympathetic?
A
Parasympathetic
22
Q
What are the meninges?
A
The three protective membranes that cover the brain and spinal cord
23
Q
From outermost to innermost, what are the three meninges?
A
- The dura mater
- The arachnoid membrane
- The pia mater
24
Q
What is the subarachnoid space?
A
The space beneath the arachnoid membrane
25
What is contained within the subarachnoid space?
Large blood vessels and cerebrospinal fluid
26
Which of the three meninges adheres to the CNS?
The pia mater
27
What are the three interconnected structures filled with cerebrospinal fluid?
- The subarachnoid space
- The central canal
- The cerebral ventricles
28
What is the main role of the cerebrospinal fluid?
To protect and cushion the brain
29
What is the small CSF-filled channel that runs the length of the spinal cord?
The central canal
30
What are the CSF-filled internal chambers of the brain?
The cerebral ventricles
31
What are the four cerebral ventricles?
- Two lateral ventricles
- The third ventricle
- The fourth ventricle
32
What connects the third and fourth ventricle?
The cerebral aqueduct
33
What are the network of capillaries that protrude into the ventricles from the pia mater and produce CSF?
The choroid plexuses
34
What path does the CSF follow to be absorbed and drained?
Absorbed from the subarachnoid space into dural sinuses that run through the dura mater and drain into the jugular veins of the neck
35
What causes hydrocephalus?
A build up of fluid in the ventricles causes the walls of the ventricles, and thus the entire brain, to expand
36
What is the mechanism that impeded the passage of toxic substances from the blood into the brain?
The blood-brain barrier
37
What characteristic of the blood vessels in the brain creates an effective blood-brain barrier?
The blood vessel walls in the brain are composed of tightly packed cells that form a barrier to the passage of many molecules
38
T or F: The blood-brain barrier impedes the passage of all large molecules.
False, certain molecules can pass through
39
What are neurons?
Cells that are specialized for the reception, conduction, and transmission of electrochemical signals
40
What composes the neuron cell membrane?
A lipid bilayer
41
What is embedded within the neuron cell membrane?
Various proteins
42
How are neurons classified?
Based on the number of processes extending from their cell bodies
43
What are most neurons classified as?
Multipolar
44
Which type of neuron has more than two processes extending from its cell body?
Multipolar neurons
45
Which type of neuron only has one process extending from its cell body?
Unipolar neurons
46
Which type of neuron has two processes extending from its cell body?
Bipolar neurons
47
What are interneurons?
Neurons with short axons or no axons at all
48
What are the two kinds of gross neural structures in the nervous system?
- Those composed primarily of cell bodies
- Those composed primarily of axons
49
What are clusters of neuronal cell bodies in the CNS called?
Nuclei
50
What are ganglia?
Clusters of neuronal cell bodies in the PNS
51
What are tracts?
Bundles of axons in the CNS
52
What are bundles of axons in the PNS called?
Nerves
53
What are glial cells/glia?
The non-neuronal cells of the nervous system
54
What is the ratio of glia to neurons in the brain?
2:3
55
What are four types of glia?
- Oligodendrocytes
- Schwann cells
- Microglia
- Astrocytes
56
What are oligodendrocytes?
Glial cells that myelinate axons of the CNS
57
T or F: Each oligodendrocyte provides only one segment of myelination?
False, each oligodendrocyte provides multiple segments, often on more than one axon
58
What are schwann cells?
Glial cells that compose the myelin sheaths of the PNS axons
59
What do schwann cells promote?
The regeneration of PNS axons
60
Each schwann cell constitutes how many myelin segments?
One
61
What are microglia?
Glial cells that respond to injury or disease by engulfing cellular debris and triggering inflammatory responses
62
What are three things microglia play a role in?
- The regulation of cell death
- Synapse formation
- Synapse elimination
63
What are the largest and most studied glial cells?
Astrocytes
64
The extensions of which type of glial cell cover the outer surface of blood vessels that course through the brain?
Astrocytes
65
T or F: Some astrocytes make contact with neurons.
True
66
Which type of glial cell can exchange chemical signals, form functional networks, control the establishment and maintenance of synapses, control the blood-brain barrier, play a role in certain form of cognition, and more?
Astrocytes
67
What is the major problem in visualizing neurons?
They are so tightly packed and their axons and dendrites are so intertwined that looking through a microscope at unprepared neural tissue reveals very little
68
What is a golgi stain?
A neural stain that completely darkens a few neurons in a slice of tissue to reveal their silhouettes
69
What are golgi stains commonly used for?
To discover the overall shape of neurons
70
What is the main drawback to golgi stains?
They provide no indication of the number of neurons in an area
71
What is a nissl stain?
A neural stain that has an affinity for the structures in neuron cell bodies
72
Nissl dyes penetrate all cells on a slide, but they only bind to what?
They only bind to the most prevalent neuron in cell bodies (ex. DNA or RNA)
73
What is the most common dye used in the Nissl method?
Cresyl violet
74
When are Nissl types most commonly used?
To estimate the number of cell bodies in an area
75
What is the procedure for producing an electron microscopy?
Thin slices of neural tissue are coated with an electron-absorbing substance, then a beam of electrons is passed through the tissue onto a photographic film
76
What is one drawback of the electron microscopy?
The images are so detailed that it can be difficult to visualize general aspects of neuroanatomical structures
77
Are scanning electron microscopes capable of providing as much magnification as a conventional electron microscopy?
No
78
What are the two types of neuroanatomical tracing techniques?
- Anterograde
- Retrograde
79
Which type of neuroanatomical tracing methods are used when tracing the paths of axons projecting away from cell bodies?
Anterograde tracing methods
80
Which type of neuroanatomical tracing methods are used when tracing the paths of axons projecting away from cell bodies?
Retrograde tracing methods
81
Directions in the vertebrate nervous system are described in relation to what?
The orientation of the spinal cord
82
What are the three axes of the vertebrate nervous system?
- Anterior-posterior
- Dorsal-ventral
- Medial-lateral
83
Which direction is referred to as anterior?
Toward the nose end of a vertebrate
84
What is another word for rostral?
Anterior
85
Which direction is referred to as posterior?
Toward the tail end/ back of the head of a vertebrate
86
What is another word for caudal?
Posterior
87
Which direction is referred to as dorsal?
Toward the back surface of a vertebrate or toward the top of the head
88
Which direction is referred to as ventral?
Toward the chest surface of a vertebrate or toward the bottom of the head
89
Which direction is referred to as medial?
Toward the midline of the body of a vertebrate
90
Which direction is referred to as lateral?
Away from the midline of the body of a vertebrate
91
What does superior mean?
Toward the top of the primate heat or brain
92
What does inferior mean?
Toward the bottom of the primate head or brain
93
What are the three different planes of the brain?
- Horizontal
- Frontal
- Sagittal
94
What are horizontal brain sections?
Any slices of brain tissue cut in a plane parallel to the top of the brain
95
What are frontal brain sections?
Any slices of brain tissue cut in a plane that is parallel to the face
96
What is another word for coronal sections?
Frontal sections
97
What are sagittal brain sections?
Any slices of brain tissue cut in a plane that is parallel to the side of the brain
98
What is a midsagittal section?
A section cut down the centre of the brain, between the two hemispheres
99
What is a cross-section?
A section cut at a right angle to any long, narrow structure of the CNS (ex. The spinal cord or a nerve)
100
What are the two areas that comprise the spinal cord?
- An inner H-shaped core of gray matter
- A surrounding area of white matter
101
What is gray matter?
Portions of the nervous system that are composed largely of cell bodies and unmyelinated interneurons
102
What are the two dorsal arms of spinal gray matter?
The dorsal horns
103
What are the two ventral arms of spinal gray matter?
The ventral horns
104
What is white matter?
Portions of the nervous system composed largely of myelinated axons
105
What are spinal nerves?
Pairs of spinal nerves attached to the spinal cord
106
To how many levels of the spine are pairs of spinal nerves attached?
31 different levels
107
Each spinal nerve divides as it nears the cord, and its axons are joined to the cord via one of which two roots?
- The dorsal root
- The ventral root
108
Are all dorsal root axons sensory/afferent or motor/efferent?
Sensory/afferent
109
What do the cell bodies of dorsal root nerves grouped together just outside the spinal cord form?
The dorsal root ganglia
110
Are neurons of the dorsal root unipolar or multipolar?
Unipolar
111
Are all ventral root axons sensory/afferent or motor/efferent?
Motor/efferent
112
Are neurons of the ventral root unipolar or multipolar?
Multipolar
113
Where do the cell bodies of ventral root neurons reside?
In the ventral horns
114
Where do spinal nerves that are part of the somatic nervous system project?
To skeletal muscles
115
Where do spinal nerves that are part of the autonomic nervous system project?
To ganglia
116
What do the three swellings on the anterior end of the neural tube eventually develop into?
The adult forebrain. midbrain, and hindbrain
117
Before birth, which of the initial three swellings does not grow into two different swellings?
The midbrain
118
What are the five swellings that compose the developing brain at birth?
- The telencephalon
- The diencephalon
- The mesencephalon (midbrain)
- The metencephalon
- The myelencephalon (medulla)
119
Which of the five major divisions of the brain is the most posterior?
The myelencephalon
120
What is the myelencephalon largely composed of?
Tracts carrying signals between the brain and the body
121
In which of the five major divisions of the brain is the reticular formation?
The myelencephalon
122
What is the reticular formation?
A complex network of about 100 tiny nuclei
123
Which brain structure occupies the central core of the brain stem, from the posterior boundary of the myelencephalon to the anterior boundary of the midbrain?
The reticular formation
124
The various nuclei of which brain area are involved in arousal, sleep, attention, movement, maintenance of muscle tone and various cardiac, circulatory, and respiratory reflexes?
The reticular formation
125
What is the myelencephalon also referred to as?
The medulla
126
Which of the five major divisions of the brain contains the pons and cerebellum?
The metencephalon
127
What is the metencephalic structure that creates a bulge on the ventral surface of the brain stem?
The pons
128
What is the large, convoluted metencephalic structure on the brain stem's dorsal surface?
The cerebellum
129
Which brain structure is thought to participate in the storage of memory of learned sensorimotor skills?
The cerebellum
130
Damage to which brain structure eliminates the ability to precisely control movements and adapt them to changing conditions?
The cerebellum
131
T or F: Cerebellar damage produces a variety of cognitive deficits.
True
132
What are the two structures that compose the mesencephalon?
- The tectum
- The tegmentum
133
What is the mesencephalon also referred to as?
The midbrain
134
What is the tectum?
The dorsal surface of the midbrain/mesencephalon
135
What are the two pairs of bumps that compose the mammalian tectum?
- The inferior colliculi
- The superior colliculi
136
What is the posterior pair of colliculi in the tectum called?
The inferior colliculi
137
Which pair of colliculi in the tectum have an auditory function?
The inferior colliculi
138
What is the anterior pair of colliculi in the tectum called?
The superior colliculi
139
Which pair of colliuli in the tectum receive major visual input and direct the body's orientation toward or away from particular visual stimuli?
The superior colliculi
140
What is the tegmentum?
The ventral division of the midbrain/mesencephalon
141
What is contained within the tegmentum?
Parts of the reticular formation, tracts of passage, and three colourful structures
142
What are the three colourful structures contained in the tegmentum?
- The periaqueductal gray
- The substantia nigra
- The red nucleus
143
What is the periaqueductal gray?
The gray matter around the cerebral aqueduct
144
Which structure in the tegmentum plays a role in mediating the analgesic (pain-reducing) effects of opioid drugs?
The periaqueductal gray
145
What is the cerebral aqueduct?
The narrow channel connecting the third and fourth ventricles
146
Which structure in the tegmentum is a nucleus whose neurons project via the nigrostriatal pathway to the striatum of the basl ganglia?
The substantia nigra
147
Which tegmentum structureis part of the mesotelencephalic dopamine system?
The substantia nigra
148
The red nucleus of the tegmentum is a structure of which system?
The sensorimotor system
149
What are the two structures that compose the diencephalon?
- The thalamus
- The hypothalamus
150
What is the two-lobed diencephalic structure that constitutes the anterior end of the brain stem?
The thalamus
151
Where do the lobes of the thalamus sit?
One lobe sits on either side of the third ventricle
152
What is the massa intermedia?
The neural structure in the third ventricel that connects the two lobes of the thalamus
153
What are sensory relay nuclei?
Nuclei of the thalamus whose main function is to relay sensory signals to the appropriate areas of the cortex
154
What are the six-layered thalamic structures that receive input from the retinas and transmit their output to the primary visual cortex?
The lateral geniculate nuclei
155
Which thalamic nuclei receive input from the inferior colliculi and project it to the primary auditory cortex?
The auditory thalamic nuclei
156
Which thalamic nuclei are important relay stations in the somatosensory system?
The ventral posterior nuclei
157
T or F: Sensory relay nuclei are one-way streets
False
158
Which diencephalic structure is located just below the anterior portion of the thalamus?
The hypothalamus
159
Which diencephalic structure plays an important role in the regulation of several motivated behaviours?
The hypothalamus
160
How does the hypothalamus exert its effects?
By regulating the release of hormones from the pituitary glad
161
What are the three structure that appear on the inferior surface of the hypothalamus?
- The pituitary gland
- The optic chiasm
- The mammillary bodies
162
What is the X-shaped structure on the inferior surface of the diencephalon?
The optic chiasm
163
At what point do the optic nerves from each eye come together and decussate?
The optic chiasm
164
What does it mean for a nerve to decussate?
To cross over to the other side of the brain
165
Are decussating fibres said to be contralateral or ipsilateral?
Contralateral
166
What is the largest, most superior/dorsal of the brain's five major divisions?
The telencephalon
167
Which of the five major brain divisions mediates the most complex functions?
The telencephalon
168
What is the cerebral cortex?
The convoluted layer of tissue that covers the cerebral hemispheres
169
Is the cerebral cortex mainly composed of myelinated or unmyelinated neurons?
Unmyelinated
170
What does it mean to be lissencephalic?
To have a cortex that is not convoluted
171
What are fissures?
The large furrows in a convoluted cortex
172
What is the longitudinal fissure?
The fissure that separates the two cerebral hemispheres
173
What are sulci?
The small furrows in a convoluted cortex
174
What are cerebral commissures?
Tracts that connect the left and right cerebral hemispheres
175
What is the largest cerebral commissure?
The corpus callosum
176
What are the two major landmarks on the lateral surface of each hemisphere?
- The central fissure
- The lateral fissure
177
Which fissure separates the frontal lobe from the parietal lobe?
The central fissure
178
Which fissure separates the temporal lobe from the frontal lobe?
The lateral fissure
179
What are the four lobes of each hemisphere?
- Frontal
- Parietal
- Temporal
- Occipital
180
What are the two distinct functional areas in each frontal lobe?
- The precentral gyrus and adjacent frontal cortex
- The frontal cortex, anterior to the motor cortex
181
Which functional area of the frontal lobe has motor function?
the precentral gyrus and adjacent frontal cortex
182
What role does the portion of the frontal cortex anterior to the motor cortex play?
Performs complex cognitive functions
183
What are the two large functional areas in each parietal lobe?
- The post central gyrus
- Posterior parts of the parietal lobes
184
What is the primary function of the postcentral gyrus in the parietal lobe?
Analyzing body sensations
185
What is the primary function of the posterior regions of the parietal lobe?
Perceiving the location of objects and our bodies
186
Which of the four brain lobes lies adjacent to the temples?
The temporal lobes
187
Which of the four brain lobes contains the hippocampus and amygdala?
The temporal lobes
188
What are the three general functional areas of the temporal cortex?
- The superior temporal gyrus
- The inferior temporal cortex
- The medial portion of temporal cortex
189
What is the superior temporal gyrus involved in?
Hearing and language
190
What is the inferior temporal cortex involved in?
Identifying complex patterns
191
Which of the four cerebral lobes is the most posterior?
The occipital lobe
192
The primary function of which cerebral lobe is visual?
The occipital lobe
193
T or F: The cerebral lobes are best thought of as functional units.
False
194
What are gyri?
The cortical ridges located between fissures or sulci
195
What is the largest gyri in the frontal lobes?
The precentral gyrus
196
What is the primary function of the precentral gyrus?
Motor
197
What is the largest gyri in the parietal lobes?
The postcentral gyrus
198
What is the primary function of the postcentral gyrus?
Somatosensory
199
What is the largest gyri in the temporal lobes?
The superior temporal gyrus
200
The neocortex constitutes how much of the cerebral cortex?
90%
200
What two categories do most neocotrical neurons fall into?
- Pyramidal cells
- Stellate cells
201
The six layers of neocortex differ from one another in terms of what three factors?
- Size
- Density
- The relative proportion of pyramidal and stellate cell bodies they contain
202
T or F: Many long axons and dendrites course vertically (at right angles to the corical layers) throught the neocortex.
True
203
Which type of cortical neurons are multipolar and have a large dendrite that extends toward the cortex surface?
Pyramidal cells
204
What are the star-shaped cortical interneurons called?
Stellate cells
205
What is the functional organization of the neocortex in vertical columns called?
Columnar organization
206
What is the limbic system?
A collection of interconnected nuclei and tracts that ring the thalamus
207
What is the limbic system involved in?
The regulation of motivated behaviours
208
What are the six major structures of the limbic system?
- The amygdala
- The hippocampus
- The cingulate cortex
- The fornix
- The septum
- The mammillary bodies
209
What is the basal ganglia?
A collection of subcortical nuclei
210
Which structure of the basal ganglia is the terminal of the dopaminergic nigrostriatal pathway?
The striatum
211
What two things make up the striatum?
- Caudate
- Putamen
212
Which structure of the basal ganglia is located between the putamen and thalamus?
The globus pallidus
213
Where does the stiatum's major output go?
The globus pallidus
214
What does the basal ganglia play a role in?
The performance of voluntary motor responses and decision-making
215
Which disease is associated with the deterioration of the pathway from the substantia nigra of the midbrain to the stiatum of the basal ganglia?
Parkinson's disease
216
Which part of the basal ganglia is in the medial portion of the ventral striatum?
The nucleus accumbens
217
What does the nucleus accumbens play a role in?
Plays a role in the rewarding effects of addictive drugs and other reinforcers
