neuro 500 -- cerebellum, diencephalon, cerebrum Flashcards
(52 cards)
more folds in brain structure?
more surface area
more neural connections
one of the components associated with intelligence of mammal
cerebellum proportion of neurons of overall brain
“Although the cerebellum accounts for approximately 10% of the brain’s volume, it contains over 50% of the total number of neurons in the brain.”
cerebellum morphology/structure/function
-highly folded surface
-increases the surface area of its outer
grey matter, allowing for a greater
number of neurons
-it accounts for about a tenth of the brain
mass but contains about half of the neurons
-things that separate the cerebellum from the cerebrum:
-tentorium cerebelli
-transverse fissure
cerebellar vermis (worm)
Vermis: the central constricted part (the worm)
cerebellum “butterfly”
Hemispheres are the wings of the butterfly
cerebellum lobes
anterior lobe
posterior lobe
—-> these two govern subconscious mvt of
skeletal mm
FLOCCULONODULAR lobe
—-> involved in equilibrium
primary fissure
separates anterior/posteiror lobes
posterolateral fissure
separates posterior lobe from flocculonodular lobe
Cerebellar peduncles
-attach the cerebellum to the brain stem
-bundles of white matter
superior cerebellar peduncle
Superior
– cerebellum to red nuclei (midbrain) + thalamus
middle cerebellar peduncle
largest
- axons carry impulses for voluntary mvts from pontine nucleus to cerebellum
Functions of the cerebellum
-primary function of cerebellum is to evaluate how well movements initiated by the cerebrum are actually carried out
-if not carried out correctly, the cerebellum detects the discrepancy and sends feedback signals to the cerebral cortex
-the feedback signals help correct the errors, smooth the movements and coordinate complex sequences of skeletal muscle contractions
cerebellum vs posture
-also regulates posture and balance
damage to cerebellum and ATAXIA
-ataxia: loss of ability to coordinate muscle mvts
E.g. ataxia
Eg blindfolded and ataxia – can’t touch the tip of nose (can’t coordinate mvts with the proprioceptive info)
-changed speech pattern due to uncoordinated speech muscles
-staggering or abnormal walking gait
—> “ataxic gait”
alcohol vs cerebellum
-alcohol inhibits activity of cerebellum so drunks show signs of ataxia
ataxia vs degenerative diseases
-ataxia can also occur from
degenerative diseases (MS, Parkinson’s), trauma, brain tumours, genetic factors, meds side effects
diencephalon structures
Thalamus
Hypothalamus
Epithalamus
Thalamus 3 major functions
-relays almost all sensory input to cerebral cortex
-contributes to motor functions by transmitting information from cerebellum and basal nuclei to primary motor area of cerebral cortex
-also relays nerve impulses between different areas of the cerebrum and plays a role in the maintenance of consciousness
thalamus nuclei
1) Anterior nucleus
2) Medial nuclei
3) Lateral group
4) Ventral group (FIVE nuclei)
5) intralaminar nuclei
6) midline nucleus
7) reticular nucleus
intermediate mass of thalamus
(aka interthalamic adhesion)
-bridge of grey matter
-joins the right and left thalamus
-found in 70% of brains
—> found more often in females
Internal medullary lamina (of thalamus)
-divides the grey matter of each thalamus
-myelinated axons that enter and leave the various thalamic nuclei (y-shaped)
Internal capsule of thalamus
Internal capsule – thick band of white matter, lateral to the thalamus
