UNIT 3: brain - external/internal surfaces Flashcards
what is the cortex made of?
six layered sheet of grey matter (clusters of cell bodies/ dendrites)- highly folded to increase surface area
what are gyri and sulci?
ridges and grooves
what are the main three sulci?
central - splits frontal and parietal lobe
lateral - splits frontal/ parietal from temporal
parieto-occipital - splits parietal from occipital
give locations of primary motor, somatosensory, auditory and visual cortex
motor - precentral gyrus (anterior to central sulcus)
somatosensory - postsensory gyrus (posterior to central sulcus)
auditory - upper part of temporal lobe - superior temporal gyrus
visual - medial surface of occipital lobe
what are the other areas in the frontal loble?
supplementary/ pre-motor cortex - coordinate motor activity outputted to PMC
pre-frontal cortex - 25% of cortex - involved in decision making, planning of future actions/ emotional & social behaviour
what is the difference between the ventral and dorsal stream from the primary visual cortex?
ventral - what? runs on lower temporal cortex- identifies the nature of objects –> fusiform gyrus - identification of faces
dorsal - where? identifies where objects are in space - ends in primary/ secondary motor cortex
what is stereognosis and what region of the brain controls it?
ability to detect shape of object by touch & texture - parietal lobe
where else does the visual cortex output to and what is it responsible for?
wernicke’s area found in temporal lobe just below lateral sulcus next to primary auditory cortex - only in left hemisphere
- language comprehension and formation of grammatical sentences
what are the two other language areas in brain?
supramarginal/angular gyrus - language and number manipulation/ analysis of semantic content
broca’s area - articulation of language - this area connected to wernicke’s area - link between production and interpretation of language
what comprises the brainstem?
midbrain, pons, cerebellum and medulla
what are the components of the midbrain?
roof -tectum - visual/ auditory reflex centres
floor - tegmentum - cranial nerve nuclei/ dopamine neurones/ ascending & descending pathways
what is the significance of substantia nigra?
grey matter where neurons rich in dopamine - axons project to motor areas - loss of nerve cells lead to parkinson’s disease = shuffling gait/ mask-like face/ tremors
why is the pons the thickest region of the brainstem?
presence of peduncles (white matter bundles)
- middle peduncle connects the cerebellum
- superior: pathway from cerebellum to cortex
- inferior: spinal cord to cerebellum
what does the medulla contain?
systems regulating arousal/ wakefulness
nuclei of cranial nerves
ascending/ descending pathways (to/from spinal cord)
what is reticular formation and what is its function?
central core of brain stem - highly interconnected network of short axon neurones
- motor control, extrapyramidal and respiratory centres
- pain modulation
- cardiovascular control
- sleep & consciousness = ARAS - Ascending Reticular Activating System (serotonin/ acetylcholine/ noradrenaline)
what can cause damage to ARAS and what does this mean?
epi/subdural haemorrhage or space-filling haemorrhage - cause brainstem compression so forces person into a coma
what are the ventricles? describe orientation
cavity filled with CSF produced by choroid plexus anterior horn - frontal lobe posterior horn - occipital lobe body - parietal lobe inferior horn - temporal lobe
describe the ventricular system
lateral ventricles communicate with 3rd ventricle via interventricular foramen - drain through cerebral aqueduct to 4th ventricle
most CSF produced in 4th ventricle which drains through lateral and medial apertures which leads to subarachnoid space surrounding brain & spinal cord
what are the functions of the thalamus, hypothalamus and basal ganglia?
thalamus - memory, consciousness, motor control & controlling flow of sensory information
hypothalamus - metabolism, autonomic nervous system, growth/gonadal function, temperature
basal ganglia - control of movement
which structures form the basal ganglia?
caudate nucleus / lentiform nucleus (putamen/ globus pallidus) in forebrain
subthalamic nucleus
which gland is connected to the thalamus and what is its function?
pineal gland
responsible for circadian rhythms controlled via autonomic nervous system
what structures form the limbic system? what functions
amygdala, hippocampus, thalamus, hypothalamus, basal ganglia, and cingulate gyrus
- factual/ emotional memory
- reward
- defensive & protective behaviour
