Brainstem and Subcortical areas Flashcards
What are the subdivisions of the brainstem
Midbrain
Pons
Medulla oblongata (projects through foramen magnum)
What cranial nerve roots can be found at the brainstem
Which cranial nuclei are on the floor of the 4th ventricle
III-XII (I and II under cerebrum base)
V-VIII nuclei on the floor of the 4th centricle
Describe the transverse section of the midbrain at the level of the superior colliculi
From dorsal to ventral Sup colliculli Oculomotor nuclei Red nucleus Substantia nigra Crus cerebri
Why is the brainstem important
What happens if there’s damage here
Contains groups of monoaminergic nuclei involved in movement control, consciousness, HR and breathing
Damage here => coma/death
What is the function of the thalamus
What does it regulate
What happens if theres damage here
All sensory info passes through here except smell
Dampens, filters info that goes to the cerebrum
Regulates
- consciousness
- sleep
- awareness
- attention
- arousal
Sleep problems, fatal insomia, forms of epilepsy
Where is the thalamus
What structure does it flank
What anatomically redundant structure is occasionally found here?
What structure is found inferior to the thalamus
Above the midbrain
2 halves of thalamus flank 3rd ventricle
-can be fused across the midline by an interthalamic adhesion (no function)
Hypothalamus inferior to thalamus
Describe the function of the basal nuclei
Involved in movement production
Cognitive reward behavioural reinforcement
-dopamine surge precedes thoughts/actions of high motivational value
Affects the modulation of what sensory info reaches the cortex from the thalamus
Name the structures found in the basal nuclei
Caudate nucleus flanks both lateral ventricles
Lentiform nucleus flanks internal capsule which flanks both lobes of thalamus
3rd ventricle under lateral ventricles
Describe the structure of the lentiform nucleus
From lateral => medial
Putamen
Globus pallidus externus
Globus pallidus internus
What 2 structures are part of the striatum
What structure is confusingly not part of the striatum
Caudate nucleus and putamen
Lentiform nucleus is not part of the dorsal striatum
Describe the relationships between the cortex and the basal nuclei
Why is the relationship important
Cortex sends excitatory impulses => striatum + substancia nigra pars compacta
Striatum sends inhibitory messages to both globus pallidi
Both globus pallidi send inhibitory messages to the thalamus
Thalamus sends excitatory impulses => cortex
Substancia nigra pars compacta moderates striatum activity
Finely balanced control of excitatory and inhibitory messages => motor control
Describe and explain the relative cross sectional thicknesses of the areas of the spinal cord
Cervical and lumbar are the thickest
-contain all motor neurones for upper and lower limbs
Describe the relative numbers of root ganglions
- dorsal
- ventral
DRG => several
VRG => 3-4
Describe the relative lengths of the nerves from the SC to the DRG
- cervical
- thoracic
- lumbar
Cervical
-1-2
Thoracic
-2-4
Lumbar
-5-25
What is the conus medullaris
What is the filum terminale
Conus medullaris
-tapered lower end of the SC
Filum terminale
-pious tissue from conus medullaris => bottom of the vertebrae
