Intro: Functions of the CNS Flashcards
1
Q
motor cortex
- location
- role
- disruption will lead to?
A
- location: front lobe
- precentral gyrus - frontal lobe gyri bordering of central sulcus
- caudal half of frotnal lobe
- role: center for voluntary movement
- disruption leads to:
- rigid paralysis
- spasticity
- hyperreflexia
- hypertonia
2
Q
describe each defect resulting from damage to the motor cortex
A
(in precentral gyrus)
- rigid paralysis - muscle cannot be moved
- spasticity - uncoordinated muscle contractions
- hyperreflexia - prolonged high amplitude rnx
- hypertonia - muscle stuck in rigid, contracted state
3
Q
frontal eye field
- location
- role
- disruption will lead to?
A
- location: frontal lobe (BA8)
- role: conjugate gaze - coordination of the contractile state of the extraoccular muscles within & between the orbit
4
Q
somatosensory cortex
- location
- role
- disruption will lead to?
A
- location: parietal lobe - esp postcentral gyrus: parietal gyri bordering the central sulcus
- role: processing of general sensations
- disruption leads to:
- paresthesia - abnormal or diminished sensations (“ex - pins & needles”)
- anesthesia (numbness - loss of sensation
5
Q
prefrontal cortex
- location
- role
- disruption leads to?
A
- location: frontal lobe - all of frontal lobe rostral to motor cortex
- role: congition and affective behavior
- disruption leads to
- depression
- manic behavior
- bipolar disorder
6
Q
special sensory cortex
- location
- role
- disruption leads to?
A
- location: can be anywhere throughout cortex, and is divided into two cnters
- primary sensory cortex: modality is processed
- accessory sensory cortex: where meaning is placed to modality, and memory of this modality is then retained
- role: processing & retaining memories associated with the special senses
- audition
- vision
- olfaction
- gustation
7
Q
parietal integration center
- location
- role
- disruption will lead to?
A
- location: along intraparietal sulcus, in caudal, superior half of parietal lobe
- role: integration of somatosensory (general), visual and auditory sensations
- damage leads to: ataxia - loss of directed motor control
8
Q
what is hemineglect?
what causes hemineglect?
A
- when patient loses awareness of “one half of the world” - ex, someone doesn’t shave half their face, only draws half of the clock
- due to cortical disruption, m/c in hte
- caudal frontal lobe
- rostral ) parietal lobe
9
Q
language
- is mediated mainly by what centers?
- in what locations?
- if disrupted, leads to what clinical presentations (s)?
A
-
language largely mediated by three regions of cortical gray matter:
- broca’s area: recognizes incomoing communications (auditory or written) - just above sylvian (lateral) fissure
- wernicke’s area: motor production of speech
- arcuate fasciculus: links broca’s and wenicke’s area
- disruption: aphasia - inability to communicate
- wernicke’s aphasia: pt cant process language, gets very frustated with others
- brocas aphasia: pt cant produce a response, gets very frustrated with self
- arcuate fasciculitis damage: decouples two centers, pt articulate words that are unrelated to incoming communication “hi how are you” “its raining outside”
10
Q
what is ideomotor apraxia?
what is it due to?
A
- the loss of learned motor skills - inability to make hand gestures, use tools
- due to disruption of the corpus collosum (white matter connecting hemispheres)
11
Q
breifly describe the role the components of the internal capsule
A
- genu: corticobulbar tract - cranial motor nerve control
- posterior limb: corticospinal tract - voluntary motor impules
12
Q
what two gyri border the central sulcus?
what major neural function does each perform?
A
- precentral gyri - frontal: contains motor cortex - voluntary movement control
- postcentral gyyri - parietal: contains somatosensory cortex - processing general sensations
13
Q
briefy summarize the CNS functions / disruptions pertaining to cortical brain
A
- motor cortex (precentral gyrus, frontal lobe) - motor control
- prefrontal cortrex (frontal lobe rostral to motor cortex) - cognition & affective behavior: depression / manifa / bipolar
- somatosensory cortex (postfcentral gyrus, parietal lobe) - general sensation processing: paresthesia/ anesthesia
- frontal eye field - conjugate gaze
- special sensory cortex - special sensation processing & retention
- parietal integration (intraparietal sulcus) - coordination: ataxia
- wernickes, brocas, arcuate fascilutis - processing & producing language
- hemineglect - loss of half the world
- corpus collosum - fine motor skills: ideomotor apraxis (gestures, tool use)
- internal capsule (corticobular, corticospinal) - cranial nerve control, voluntary motor impulses
14
Q
what comprises the diencephalon?
A
- epithalamus
- thalamus
- hypothalamus
15
Q
describe the role of the thalamus in CNS function
A
is organized into well defined functional nuclei, all of which have recipricol connections with virtually every part of the cerebral cortex
18
Q
for each of the following thalamic nuclei, list the 1. cortical region it projects to and 2. signal transmitted
- anterior
- dorsomedial
- dorsolateral
- ventral anterior
- ventral lateral
- ventral posterolateral
- ventral posteromedial
- medial geniculate
- lateral geniculate
- intralaminar
A
20
Q
mamillary bodies:
- location
- role in CNS function
- damage can lead to?
A
- location: inferior / ventral border of hypothalamus
- role: memory formation
-
begin the papez circuit:
- mamillary bodies anterior nucleus of the thalamus
- through the thalamic-cortical recipricol connection, the anterior nucleus is linked to the cingulate gyrus (portion of cortex paralleling the corpus collosum)
- from here, the fornix carries the signal to the hippocampus (cerebral cortex extending from uncus & forming floor of temporal lobe)
- from hippocampus back to mammary body
-
begin the papez circuit:
- disruption: amnesia (impaired memory formation)
