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HYMIDST.MCQ
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1993-08-06
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D:Created 14.47 06/08/1993
D:Subject : Physiology
D:Topic : Hypothalamus, midbrain, brain stem
D:Level : Moderate
D:
D:Authors : Department of Physiology
D: The University
D: Leeds LS2 9NQ
I:MCQ SB 1
G:3
G:1:Dental Students
Q:1,2,3,4,5,6,7,8,9,10
G:2:Medical Students
Q:1,2,3,4,5,6,7,8,9,10
G:3:Science Students
Q:1,2,3,4,5,6,7,8,9,10
T:A
L:2
#:1
G: 10464 1 2 3
S:2
:Decerebrate rigidity:
:
B:N:5
B:1:F:2
:is produced by transection of the brainstem at the
:pontomedullary junction
B:2:T:2
:is produced by transection of the brainstem between the
:superior and inferior colliculi
B:3:F:1
:increases tone in flexor muscles
B:4:T:1
:results in an increased level of gamma efferent discharge
B:5:T:1
:can be relieved by lesions of the vestibular nuclei
F:7
:The transection that produces a classical decerebrate
:preparation is in the midbrain, between the superior and
:inferior colliculi. The hypertonus that develops can be seen
:in extensor muscles and is due to hyperactivity in gamma
:motoneurones. The rigidity is produced largely by the
:vestibular nuclei. Transection of the midbrain removes the
:inhibitory influences of the cortex and basal ganglia.
E:------
#:2
G: 10464 1 2 3
S:1
:The brainstem reticular formation:
B:N:5
B:1:T:2
:contains neurones that receive inputs from many sensory
:systems
B:2:T:2
:contains regions which when stimulated reduce the tone of
:somatic muscle
B:3:T:1
:regulates the level of consciousness
B:4:T:2
:is an intermediate relay through which the motor cortex
:and cerebellar functions are linked
B:5:F:2
:is the intermediate relay through which the major
:projections from the basal ganglia influence muscle tone
F:14
:The ascending reticular activating system within the
:rostral brainstem regulates the level of consciousness. This
:system receives convergent inputs from many sensory systems,
:such as vision, hearing, muscle and skin. Stimulation of
:these areas of the brainstem causes waking of sleeping animals
:and is accompanied by an arousal pattern in the EEG.
N:The descending reticular formation arises in the medulla, pons
:and midbrain; the medial medullary reticular formation causes
:inhibition of skeletal muscle tone, as does the pontine
:reticular formation.
N:There are pathways from the cerebral cortex to the cerebellum
:that involve synapses in the pontine reticular formation (or
:in the inferior olive). The main projection area from the
:basal ganglia is the cerebral cortex.
E:------
#:3
G: 10464 1 2 3
S:2
:The following fibre tracts project contralaterally:
:
B:N:5
B:1:T:1
:corpus callosum
B:2:T:1
:lateral cortico-spinal tract
B:3:F:1
:internal capsule
B:4:T:1
:anterior commissure
B:5:F:1
:fasciculus gracilis
F:1
:No explanation available
E:------
#:4
G: 10464 1 2 3
S:1
:Functions ascribed to the hypothalamus include:
B:N:5
B:1:F:1
:control of the pupillary reflexes
B:2:T:1
:regulation of body temperature
B:3:T:1
:secretion of antidiuretic hormone
B:4:F:1
:co-ordination of voluntary movement
B:5:T:1
:maintaining a state of arousal
F:5
:The connections of the hypothalamus with the autonomic
:nervous system, the posterior pituitary and the non-specific
:ascending reticular formation are responsible for effects of
:this part of the brain on body temperature, water excretion
:and the sleep/walking cycle.
E:------
#:5
G: 10464 1 2 3
S:1
:The following are components of the limbic system:
B:N:5
B:1:F:1
:the anterior commissure of the hypothalamus
B:2:T:2
:connections between the hypothalamus and the amygdala (via
:the stria terminalis)
B:3:T:2
:connections between the hypothalamic septum and the
:hippocampus (via the fornix)
B:4:T:2
:connections between the hippocampus and the mammillary
:bodies (via the fornix)
B:5:F:1
:the corpus callosum
F:15
:The stria terminalis contains fibres travelling in both
:directions between the hypothalamus and the amygdala (in the
:temporal lobe). The fornix contains fibres travelling in both
:directions between the hippocampus (in the temporal lobe) and
:(a) the septum at the anterior end of the hypothalamus, and
:(b) the mammillary bodies. The latter have a major projection
:to the cingulate gyrus. The hippocampus also receives inputs
:from the amygdala, the temporal cortex and the cingulate
:gyrus.
:The corpus callosum and the anterior commissure are not parts
:of the limbic system: they carry fibres from one side of the
:brain to the other. The anatomy is complicated, and the
:functions of the limbic system are related to emotion and
:mood, and their expression in motor, autonomic and endocrine
:behaviour.
E:------
#:6
G: 10464 1 2 3
S:1
:The cingulate gyrus:
B:N:5
B:1:T:1
:receives inputs from the mammillary bodies
B:2:T:1
:receives inputs from the frontal cortex
B:3:F:2
:receives visual information from the lateral geniculate
:body
B:4:F:1
:is concerned with the regulation of the direction of gaze
B:5:T:2
:stimulation of the cingulate gyrus rise to cardiovascular
:changes
F:13
:The cingulate gyrus is part of the limbic system and
:receives its inputs from the mammillary bodies and the frontal
:cortex: stimulation causes cardiovascular changes. The
:calcarine gyri receive visual information and information
:relevant to the control of the direction of gaze is channelled
:through subcortical association fibres to the frontal eye
:fields - in front of the motor area. The frontal eye fields
:project to the paramedian pontine reticular formation and the
:reticular formation of the midbrain which integrate
:information necessary for the control of extra-ocular
:muscles - from the eye via the superior colliculus, from the
:vestibular apparatus via the medial longitudinal bundle, and
:from the cerebellum.
E:------
#:7
G: 10464 1 2 3
S:1
:Consider the functions of dopamine in the brain:
B:N:5
B:1:T:2
:it is found in neurones in the substantia nigra that
:project to the striatum (basal ganglia)
B:2:T:2
:it is released in the hypothalamus and acts as a prolactin
:inhibitory releasing factor in the anterior pituitary
B:3:T:2
:dopamine-containing neurones in the ventromedial midbrain
:project to the limbic system
B:4:T:2
:drugs which block the action of dopamine are used to treat
:schizophrenia
B:5:F:1
:dopamine is the transmitter in the raphe-spinal pathway
F:13
:In the midbrain, the lateral dopaminergic neurones arise
:the substantia nigra and project to the putamen and caudate
:nucleus of the neostriatum. Destruction of these neurones
:leads to Parkinson's disease. The ventromedial mesencephalic
:dopaminergic neurones project to the amygdala, septum and
:olfactory tubercle of the limbic system, and to the frontal
:and cingulate cortex. Most of these axons pass through the
:medial forebrain bundle. Other short neurones in the
:hypothalamus that contain dopamine release it to inhibit the
:release of prolactin by the anterior pituitary. Drugs that
:increase the rate of release of dopamine produce a psychosis
:similar to schizophrenia. There are no known dopaminergic
:pathways from the brainstem to the cord.
E:------
#:8
G: 10464 1 2 3
S:2
:Consider the catecholaminergic neuronal systems of
:the brain:
B:N:5
B:1:T:1
:the main noradrenergic nucleus is the locus coeruleus
B:2:T:2
:noradrenergic neurones in the brainstem project to he
:limbic system via the medial forebrain bundle
B:3:F:1
:dopaminergic neurones in the medulla project to the cord
B:4:T:4
:if animals are allowed to electrically stimulate their own
:brains by pressing a switch, self-stimulation is repeated at
:rates of up to 100/min if the structure being stimulated
:contains catecholaminergic neurones
B:5:T:3
:intracranial self-stimulation is abolished by 6-
:hydroxydopamine, a drug which destroys catecholaminergic
:neurones
F:6
:Noradrenergic neurones from the brainstem project to the
:limbic system and spinal cord. Dopaminergic neurones do not
:project to the cord. Intracranial self stimulation is
:repeated if the site of the stimulus contains
:catecholaminergic neurones. The optimum site is the medial
:forebrain bundle.
E:------
#:9
G: 10464 1 2 3
S:1
:Consider serotonergic neurones in the brain:
B:N:5
B:1:T:1
:they lie in the midline of the brainstem
B:2:T:1
:they project to the limbic system and basal ganglia
B:3:T:1
:some also contain substance P
B:4:T:2
:serotonergic raphe-spinal neurones are concerned with
:antinociception
B:5:F:2
:serotonin is the transmitter in pathways originating form
:the periaqueductal grey matter
F:6
:Midline structures in the brainstem such as the raphe
:nuclei can contain serotonin, and sometimes substance P as
:well. These neurones project to the limbic system, basal
:ganglia, cortex, cerebellum and spinal cord. The role of
:serotonergic raphe-spinal neurones includes modulation of
:transmission of noxious information through the dorsal horn.
E:------
#:10
G: 10464 1 2 3
S:2
:The main central connections of the optic nerve
:include the following:
B:N:5
B:1:F:1
:the nucleus of the inferior colliculus
B:2:F:1
:the mamilliary bodies
B:3:F:1
:the medial geniculate body
B:4:T:1
:the nucleus of the superior colliculus
B:5:T:1
:the lateral geniculate body
F:5
:The axons of retinal ganglion cells project to the lateral
:geniculate nucleus where they synapse on the main visual
:pathway to the cortex. Some fibres also pass to the superior
:colliculi which has a retinotopic map and is concerned with
:the direction of gaze.
E:------
::