Neuroanatomy (Part 2) Flashcards
What are the names of the 6 layers of the cerebral cortex?
- Layer 1: Molecular (plexiform) Layer
- Layer 2: External granular layer
- Layer 3: External pyramidal layer
- Layer 4: Internal granular layer
- Layer 5: Internal pyramidal layer (ganglionic)
- Layer 6: Multiform layer
What is found in the Molecular (plexiform) layer of the cerebral cortex?
- Very few neuronal somata.
- Apical dendrites of cells located in deeper cortical layers.
- Axons passing through or making connections in this layer.
- Axons arising from within this layer often travel parallel to the pia.
What is found within the external granular layer of the Cerebral cortex?
- Small granule cells (local interneurons that inhibit other cortical cells) and some slightly larger pyramidal cells.
- Communications with ipsilateral cortical areas (via association fibers).
What is found in the external pyramidal layer of the Cerebral Cortex?
- Primarily small-to-medium-sized pyramidal neurons projecting from the cortex.
- Communications with homotopic contralateral cortices (via commissural fibers).
What is found within the internal granular layer of the Cerebral cortex?
- No pyramidal neurons.
- Interneurons receiving ascending sensory (thalamocortical) input and projecting to layers II/III.
- Contains dense band of tangential axons that form the outer band of Baillarger, which is hypertrophic and visible to the naked eye in a discrete occipital region (forming the stria Gennari of the striate cortex).
What is contained in the internal pyramidal (ganglionic) layer of the Cerebral Cortex?
- Medium-to-very-large pyramidal neurons.
- A major source of cortical output to the brainstem and spinal cord.
- Contains a dense band of tangential axons (i.e., inner band of Baillarger).
What is contained within the multiform layer of the Cerebral cortex?
- An assortment of cell types, including a few pyramidal cells.
- Small cells receive input from the thalamus and from cortical layers II, III, and V.
- Axons of the cells in this layer project to superficial cortical layers and also subcortically, for example, to the thalamus.
What cells form the output pathway from the Cerebral cortex?
Pyramidal cells (layers II, III, V, and VI)
Which cerebral layer are the largest pyramidal cells of the primary motor cortex that can make synaptic connections with caudal spinal motor neurons found?
Layer 5
Where do axons of most thalamo-cortical neurons end?
Layer IV of cerebral cortex
Where do axons of cortical association neurons end?
may end in any of the layers but mainly in layers II, III and IV.
Deep within the cerebral white matter are nuclei forming what?
Basal Ganglia
The BASAL GANGLIA are groups of neurons that are concerned with what?
The initiation and organization of movement.
What are the major components of the basal ganglia?
o Caudate nucleus
o Putamen
o Globus pallidus
o Claustrum
The caudate nucleus + putamen of the basal ganglia make up what?
Striatum
The putamen + globus pallidus of the basal ganglia make up what?
Lentiform nucleus
The basal ganglia lie close to the ______ and to the functionally linked _______and_______.
- lateral ventricles
- thalamus
- subthalamus
The thalamus relays virtually all sensory input to ____. It also processes___ from the ____ and _____to regulate the _____ and hence movement.
- sensory cortices
- output
- basal ganglia
- cerebellum
- motor cortex
The hippocampus is a collection of neurons that processes much _____ that is destined for long-term storage in memory within ____.
- Sensory information
- cortical circuitry
The amygdala participates in _____, perhaps assigning an ____.
- emotional regulation
- emotional valence to memory
What are the 3 forms of white matter?
- Projection
- Association
- Commisural
What is the function of Association white matter?
Connects one cortical region to another within the same hemisphere (e.g., superior longitudinal fasciculus).
What is the function of commisural white matter?
Connects homotopic cortical sites between hemispheres (e.g., corpus callosum).
What is the function of projection white matter?
Connects cortical and subcortical sites (e.g., internal capsule).
What are the components of the brainstem?
midbrain, pons (cerebellum may be included), and medulla oblongata.
What are prominent landmarks in a horizontal slice of the midbrain?
- cerebral peduncle,
- substantia nigra,
- medial lemniscus
- red nucleus.
What are prominent landmarks in a horizontal slice of the pons?
- corticospinal tract,
- medial lemniscus
- middle cerebellar peduncles
What are prominent landmarks in a horizontal slice of the medulla oblongata?
- pyramid
- olive
- medial lemniscus
The shape of the horizontal slices of the spinal cord vary with the rostro-caudal level of the section (T/F)
TRUE!!
-For example, there is only one dorsal column on either side at lumbar and lower thoracic levels, but there are two dorsal columns bilaterally at cervical levels.
The more ____of the ______ carries sensory information from the legs, while the more _____ of the _____ carries sensory information from the arms
- medial
- dorsal columns
- lateral
- dorsal columns
Where are the two enlargements of the spinal chord located?
- Cervical enlargement
- Lumo-sacral enlargement
What do the enlargements of the spinal chord reflect?
greater numbers of cells required at these levels to process sensory and motor signals for the arms and legs.
