week 4 Flashcards
Describe declarative memory
factual information
life events
available to consciousness
easily formed / forgotten
Describe non-declarative memory
procedural memory
motor skills
not available to conciousness
less easily formed / forgotten
Describe ballistic movements
based largely on pre-programmed instructions
rapid but at the expense of accuracy
little opportunity for compensation for unexpected changes
Describe pursuit of visual feedback movements
motor command continually updated to sensory feedback
highly accurate but slow
What are the main non cortical brain structures involved in the control of movement?
the basal ganglia
What is the main input to the basal ganglia?
the prefrontal cortex - intended movement
What is the main output of the basal ganglia?
pre-motor area (via thalamus)
What are the functions of the basal ganglia?
initiation of movement
planning if complex voluntary movement
What is the function of the cerebellum in the control of movement?
co-ordination and smooth execution of movements
error detection in motor learning
What can be the result of cerebellar damage?
cerebellar ataxia - poor coordination
Describe the lateral pathways
pyramidal neurons in M1 project to the spinal cord (corticospinal tract) and red nucleus (rubrospinal tract)
control of voluntary movement of distal muscles - fine control of the hand
Describe the ventromedial pathways
control of axial muscles (posture)
descending systems synapse on motor neurons or interneurons in the spinal cord
What drives the activity of stepping?
intrinsic circuits in the spinal cord can produce rhythmic motor neuron activity which drives stepping.
Alternative activity of flexor and extensor muscles coordinated across the two limbs
Describe a possible mechanism for the rhythmic activity in an interneuron
the membrane depolarises ue to continuous input (descending systems) Na+ and Ca2+ flow into the cells Ca2+ activates K+ channels K+ flows out of the cell The membrane hyper polarises Ca2+ stops flowing into the cell Potassium channels close The membrane depolarises and the cycle repeats
WHat is the most important mechanism for the strength of muscle contraction?
the recruitment of motor units
What is the equation of cerebral perfusion pressure?
CCP = MAP - ICP
What are the signs of increasing ICP?
decreasing GCS
diminishing pupil response to light
lateralising signs
What is meant by a battle sign?
bruising over the mastoid process
bruising over middle cranial fossa
What is the pterion?
junction of frontal, parietal and temporal bones
translucent to light
injury here is very vulnerable to fractures
middle meningeal artery is below this
Describe an uncal herniation
first part to herniate through th tentorium cerebellum and may compress occulomotor parasympathetic fibres which innervate the pupil - leads to fixed dilated pupil
What is attention?
a global cognitive process encompassing multiple sensory modalities, operating across sensory domains
What is meant by arousal?
a general state of wakefulness and responsivity
What is meant by vigilance?
capacity to maintain attention over prolonged periods of time
What is divided attention?
ability to respond to more than one task at once
What is selective attention?
ability to focus on one stimulus while suppressing competing stimuli
What is the result of impaired arousal?
drowsiness
What is the result of impaired vigilance?
impersistance
What is the result of impaired divided and selective attention?
distractible
What areas of the brain are involved in attention?
prefrontal cortex
parietal corteex
limbic cortex
ascending reticular activating systems
What is the result of damage to the prefrontal cortex, limbic cortex or parietal cortex?
inattention, neglect
What is the result to damage of the ARAS?
drowsiness, delirium or coma
What are the components of the limbic system?
cingulate gyrus hippocampus amygdala orbital and prefrontal cortex mamillary bodies
WHat are the components of the ARAS?
brainstem nucleus
thalamic nuclei
cortex
Describe working memory
immediate recall of small amounts of verbal and spacial information
visual = non-dominant parieto-occipitaq lobe
Phonological = dominant perisylvian areas
What are the two types of long term memory?
explicit (declarative)
implicit (procedural)
WHat are the two types of explicit memory?
episodic and semantic
What at the the two types of implicit memory?
motor skills and classical conditioning
Describe episodic memory
personally experiences, temporarily specific episodes / events
Describe the anatomy of episodic memory
extended limbic system (circuit of paper)
medial temporal lobe, particularly hippocampus and entorhinal cortex
diencephalon - maxillary bodies and thalamic nuclei
Dorsolateral prefrontal cortex
Describe somantic memory
factual information and vocabulary
independent of context, time and personal relevance
Describe the anatomy of semantic memory
not depedent on the limbic system
left anterior temporal lone is key integrative region
anterior temporal cortex and and angular gyrus integrate incoming information
Describe the anatomy of implicit memory
networks involving the basal ganglia and cerebellum
How much of the external acoustic meatus is cartilage?
the outer 1/3
WHat glands produce earwax?
ceraminous glands
Describe the histology of the tympanic cavity
presudostratified columnar epithelium - respiratory epithelium
cilia to waft mucous
goblet cells to produce mucous
WHat muscles protect the ear from loud noises?
tensor tympani and stapedius
What nerve innervates the muscles that protect the ossicles?
CN VII
