cerebral cortex Flashcards
What does the cerebral cortex cover?
The cerebral cortex covers the cerebral hemispheres.
What is the composition of the cerebral cortex?
The cerebral cortex is made up of gray matter and contains around 10 billion neurons.
What increases the surface area of the cerebral cortex?
The surface area is expanded by gyri (ridges) and sulci (grooves).
What is the thickness of the cortex at the crest of a gyrus?
The cortex is about 4.5 mm thick at the crest of a gyrus.
What is the thickness of the cortex in the sulcus?
The cortex is about 1.5 mm thick in the sulcus.
What components make up the cerebral cortex?
The cerebral cortex consists of nerve cells, nerve fibers, neuroglia (supporting cells), and blood vessels.
What are giant pyramidal cells (Betz cells)?
Giant pyramidal cells (Betz cells) can be up to 120 µm in size and are located in the motor cortex.
What do the apical dendrites of pyramidal cells extend toward?
The apical dendrites extend toward the pia mater.
What do the basal dendrites of pyramidal cells do?
The basal dendrites spread laterally.
What is the axon of a pyramidal cell like?
The axon originates from the cell body and may connect within the cortex or project into deeper brain regions (white matter).
What are stellate cells?
Stellate cells are small, polygonal cells with multiple dendrites and a short axon that typically synapses with nearby neurons.
What are fusiform cells?
Fusiform cells have a vertical orientation and are mostly found in the deepest cortical layers.
Where do the inferior dendrites of fusiform cells branch?
The inferior dendrites branch in the same layer.
Where do the superficial dendrites of fusiform cells extend?
The superficial dendrites extend toward the cortical surface.
Where do the axons of fusiform cells project?
The axon projects into the white matter as projection, association, or commissural fibers.
What are horizontal cells of Cajal?
Horizontal cells of Cajal are small, fusiform cells located in the most superficial cortical layers.
What direction do the dendrites of horizontal cells of Cajal extend?
The dendrites extend horizontally.
What is the axon of horizontal cells of Cajal like?
The axon runs parallel to the cortical surface, making contact with pyramidal cell dendrites.
What are cells of Martinotti?
Cells of Martinotti are small, multipolar cells present throughout the cortex.
Where do the axons of cells of Martinotti project?
Axons project toward the pia mater, often terminating in the most superficial cortical layer.
What are radial fibers?
Radial fibers run perpendicular to the cortical surface.
What types of fibers are included in radial fibers?
Radial fibers include afferent fibers from the thalamus and axons from pyramidal, stellate, and fusiform cells.
What are tangential fibers?
Tangential fibers run parallel to the cortical surface.
What types of fibers are included in tangential fibers?
Tangential fibers include collateral branches of afferent fibers and axons from horizontal and stellate cells, as well as collateral branches from pyramidal and fusiform cells.