Lecture 18 Flashcards
(137 cards)
1
Q
What are the subdivisions of the forebrain?
A
- Telencephalon (cerebrum)
- Diencephalon
(Thalamus
Hypothalamus
Subthalamus
Epithalamus )
2
Q
What does the telencephalon develop into?
A
The cerebrum
3
Q
What are the 4 main components of the Diencephalon?
A
Thalamus
Epithalamus
Hypothalamus
Subthalamus
4
Q
Which is the sensory relay station?
A
Thalamus
5
Q
What does the epithalamus do?
A
Emotions and cardiac rhythms
6
Q
What controls motor functions?
A
Subthalamus
7
Q
What does the hypothalamus do?
A
Major control center of endocrine and autonomic nervous systems
8
Q
What does the subthalamus contain?
A
A large subthalamic nucleus that is functionally considered a part of the basal ganglia
9
Q
Each side of the brain has what?
A
A thalamus
It is in the center of the brain
10
Q
What is the thalamus considered?
A
“Gateway to the cerebral cortex”
11
Q
Where does nearly all input to the cerebrum synapse?
A
In thalamic nuclei (“screen out information”)
12
Q
What is the main function of the thalamic nuclei?
A
Relate and modulate information (limbic, motor, and all sensory modalities besides olfaction) incoming from the periphery to the cerebral cortex
13
Q
What are the 5 major functional groups of the thalamic nuclei?
A
Lateral group
Medial group
Anterior group
Ventral group
Posterior group
14
Q
What does the lateral group do?
A
Somatosensory output to associates ares of cortex
15
Q
What does the medial group do?
A
Emotions
16
Q
What does the anterior group do?
A
Part of limbic system (memory and emotion)
17
Q
What does the posterior group do?
A
Relay of signals
Visual - to occipital lobe (visual cortex)
Auditory - to temporal lobe (auditory cortex)
18
Q
What does the ventral group do?
A
Somatosensory output to primary cortex (postcentral gyrus)
Signals from cerebellum and basal nuclei to motor areas of cortex
19
Q
What is the epithalamus?
A
A small mass of tissue composed mainly of habenula and pineal body (gland)
20
Q
What does the epithalmus produce?
A
Melatonin
21
Q
What is the epithalamus wired with?
A
Wired with the limbic system and basal ganglia
22
Q
What does the epithalamus participate in?
A
In regulation of the body’s circadian (24 hour) rhythms
23
Q
What is the overall function of the hypothalamus?
A
The integration of body functions for the maintenance of homeostasis
24
Q
How does the hypothalamus maintain homeostasis?
A
By controlling endocrine autonomic, and somatic behavior
25
How does the hypothalamus receive internal stimuli?
Via receptors for circulating hormones
26
How does the hypothalamus sense external stimuli?
Via the spinothalamic tract (pain and temperature information
27
How many bilateral nuclei are there?
11
28
What hypothalamic function does the suprachiasmatic nucleus link with?
Biological clock
29
What hypothalamic function does the mammillary nucleus link with?
Memory formation
Relay between limbic system and thalamus
30
What hypothalamic function does the dorsomedial nucleus link with?
Rage and other emotions
31
What monitors body temperature?
Neurons of the preoptic area (POA) of the hypothalamus
32
What does the ventromedial nucleus do?
“Satiety center”
Decreases eating/glucose sensing
33
What does the lateral (complex) nucleus do?
“Feeding center”
Hunger/increases eating
34
What does the arcuate nucleus do?
Receives signals from GI tract and adipose tissue (leptin) and regulated both satiety and feeding centers
35
What does the arcuate nucleus release?
Hypothalamic hormones secreted by axon terminals into the hypophyseal portal veins to control anterior pituitary hormone release
36
What does the (medial) preoptic nucleus release?
Gonadotropin releasing hormone (GnRH)
37
What does the GnRH stimulate?
Release of LH FSH by pituitary gland
38
The paraventricular (PVN) and supraoptic nuclei both produce what?
Produce the peptides oxytocin and ADH (antidiuretic hormone or vasopressin)
39
Where are oxytocin and ADH released from?
From neuronal axons into the capillaries of the posterior pituitary
40
The PVN and supraoptic nuclei are both what?
Both hormones and neurotransmitters
41
What does PVN release in response to stressor signals?
Corticotropin-releasing hormone (CRH)
42
What stimulates the release of ATCH by the pituitary gland?
Corticotropin releasing hormone (CRH)
43
What are the 5 lobes of the cerebrum?
Frontal lobe
Insula
Partietal lobe
Occipital lobe
Temporal lobe
44
What are the functions of the frontal lobe?
Planning judgement
Speech production
Voluntary motor control
45
What are the functions of the parietal lobe?
Integrates general sense (pain, temp, touch, pressure, vibration, and proprioception)
Taste information
46
What is the function of the occipital lobe?
Principal visual center of brain
47
What are the functions of the insula?
Visceral sensation
Empathy
48
What are the functions of the temporal lobe?
Hearing
Smell
Verbal, visual, and auditory memory
Language comprehension (Wernicke’s area)
49
What are the three types of white matter tracts in the brain?
Association tracts
Projection tracts
Commissural tracts
50
Most of the volume of cerebrum is what?
White matter (myelinated fibers bundled into large tracts)
51
How are the white matter tracts classified?
According to the direction they run
52
What do the long fibers in association tracts connect?
Lobes
53
What do short fibers in association tracts connect?
Gyri within a lobe
54
What do intrahemispheric tracts connect?
Different regions within the same cerebral hemisphere
55
What is the cingulum?
Core part of the limbic system
56
Where do projection tracts extend?
Vertically between higher and lower brain and spinal cord centers
57
What two types of tracts can projection tracts be?
Efferent or afferent
58
What is the fornix?
The main efferent system of the hippocampus and important part of the limbic system
59
What is the corona radiata also known as?
Corticospinal tract
60
What does the anterior commisure do?
Plays a role in the interhemispheric transfer of olfactory information between temporal lobes
61
What do commissural tracts do?
Cross from 1 cerebral hemisphere to the other through bridges called commissures
62
What is the corona radiata (radiating crown) in the brain formed by?
By nerve fibers (white matter) that make up the inner capsule
63
What does the radiata crown do?
Connects the cerebral cortex to lower areas of the brain and spinal cord
64
What is the radiata crown composed of?
A large set of projection fibers (afferent and efferent)
65
Where is neural integration carried out?
In the gray matter of the cerebrum
66
What is the cerebral cortex?
A layer covering the surface of the hemispheres
67
How many mm and what % brain mass is the cerebral cortex?
2-3 mm
40 % of brain mass
68
What is hypothesized about the cerebral cortex?
That the cortex should be viewed as concentric rings of allocortex, mesocortex, and isocortex
69
What is the last cortex region to evolve?
The neorocortex (or isocortex)
70
What is the highly convoluted outer layer of the brain?
The cerebral cortex
71
What are the 2 principle types of neurons in the cerebral cortex?
Small pyramidal cells
Steliate cells (star shaped
72
What role do small pyramidal cells play in the cerebral cortex?
Axons leave the cortex and connect with other parts of the CNS
73
What role do steliate cells play in the cerebral cortex?
Receive sensory input
Process information locally
74
How many layers are in the neocortex (isocortex)?
6
(I-VI)
75
What % does the neocortex (isocortex) take up in the cerebral cortex?
90%
76
What are basal nuclei (basal ganglia)?
Groups of nuclei (clusters of neurons) curried deep in the white matter, lateral to the thalamus
77
What is the function of basal nuclei?
Involved in motor control
Receive input from the substantia nigra of the midbrain and motor areas of the cortex (and send signals back)
78
What are the 3 types of basal nuclei?
Caudate
Putamen
Globes pallidus
79
What are the 2 types of related basal nuclei?
Subthalamus
Substantia nigra
80
What is the major part of the basal nuclei?
The corpus striatum
81
What is the limbic system?
Important center of emotion and learning
82
What do most limbic system structures have centers for?
Gratification
Aversion
83
What is gratification?
Sense of pleasure or reward
84
What is aversion?
Unpleasant sensations (fear or sorrow)
85
What regulates impulses, compulsions, and drives?
Medial prefrontal cortex and orbitofrontal cortex
86
What is the emotion center in the limbic system?
Amygdala
87
Why is called the limbic system?
Limbus = ‘border’
Because its structures lie along a horseshoe shaped area of cortex that appears to be a border between the cerebral cortex and the sub cortical structures of the diencephalon
88
What structure has the function of explicit (conscious) memories?
Hippocampus
89
How are the 12 cranial nerves numbered?
I-XII
Starting with the most rostral pair (front or brain)
90
Where do the cranial nerves primarily arise from?
From the base of the brain
91
Where do the cranial nerves carry fibers?
Between the brainstem and ipsilateral receptors and effectors
92
What does a lesion in 1 side of the brainstem cause?
Causes a sensory or motor deficit on the same side of the head
(Exceptions: II and IV nerves)
93
Where is the olfactory bulb from?
The olfactory nerve
94
What is the I nerve?
Olfactory nerve
95
What is the II nerve?
Optic nerve
96
What is the III nerve?
Oculomotor nerve
97
What is the IV nerve?
Trochlear nerve
98
What is the V nerve?
Trigeminal nerve
99
What is the VI nerve?
Abducens nerve?
100
What is the VII nerve?
Facial nerve
101
What is the VIII nerve?
Vestibulocochlear nerve
102
What is the IX nerve?
Glossopharyngeal nerve
103
What is the X nerve?
Vagus nerve
104
What is the XII nerve?
Hypoglossal nerve
105
What is the XI nerve?
Accessory nerve
106
Which nerves are classified as sensory?
I, II, VIII
107
Which nerves are classified as motor?
III, IV, VI, XI, XII
108
Which nerves are classified as mixed?
V, VII, IX, X
109
What is the function of the olfactory nerve (I)?
Sense of smell
110
What is the associated impairment of the olfactory nerve (I)?
Anosmia
111
What are the functions of the vestibulocochlear nerve (VIII)?
Hearing and equilibrium
112
What are the associated impairments of the vestibulocochlear nerve (VIII)?
Sensorineural deafness
Nystagmus
113
What is the function of the optic nerve (II)?
Transmits visual signals from the retina of the eye to the brain
114
What is the associated impairment of the optic nerve (II)?
Blindness
115
What is the function of the abducens nerve (VI)?
Eye movement: directs the gaze laterally
116
What does the abducens control?
The lateral recuts muscle
117
What is the function of the oculomotor nerve (III)?
Innervation to the pupil and lens (focusing and pupil dilation), the upper eyelid, and the eye muscles that allow for visual tracking and gaze function
118
What are the associated damages of the oculomotor nerve (III)?
Fixed and dilated pupil
119
What is the function of the trochlear nerve (IV)?
Eye movement: direct face slightly downward and rotate the top of the eyeball toward the nose
(Compensating for head movements)
120
What is the associated impairments of the trochlear nerve (IV)?
Double vision
121
What are the 3 branches of the TRIgeminal nerve (V)?
Ophthalmic division (V1) *sensory*
Maxillary division (V2) *sensory*
Mandibular division (V3) *mixed*
122
What is the function of the trigeminal nerve (V)?
Mastication (chewing)
123
What is the largest cranial nerve?
The trigeminal nerve
124
What is the most important sensory nerve of the face?
The trigeminal nerve
125
What is the associated impairment of the V1 nerve?
Absence of blink reflex
126
What is the associated impairments of V2 nerve?
Loss of sense of touch, pain, and temperature
127
What happens when one of the V nerve divisions is damaged?
Results in loss of sensation from the respective region of the face
128
What is the function of the facial nerve (VII)?
Sensory for taste
129
What is the major motor nerve to the facial muscles?
The facial nerve (VII)
130
What are the 5 branches of the facial nerve from top to bottom?
Temporal
Zygomatic
Buccal
Mandibular
Cervical
131
What is the function of the accessory nerve (XI)?
Controls swallowing and the neck and shoulder muscles
132
Why is it called the ‘accessory’ nerve?
It is not a true cranial nerve: it arises from the upper spinal cord
133
What are the associated impairments of the glossopharyngeal nerve (IX)?
Difficulty swallowing, loss of bitter and sour taste sensations
134
What is the function of the hypoglossal nerve (XII)?
Controls tongue movements of speech, food manipulation, and swallowing
135
Which nerve has the most extensive distribution of any cranial nerve?
The vagus nerve (X)
136
What is the function of the vagus nerve (X)?
Controls cardiac, pulmonary, digestive, and urinary function
Swallowing, speech, regulation of viscera
137
What are the associated impairments of the vagus nerve (X)?
Hoarness or loss of voice
Impaired swallowing
Fatal if both are cut
